WavPack encoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 2987 insertions, 0 deletions

diff --git a/libavcodec/wavpackenc.c b/libavcodec/wavpackenc.c
new file mode 100644
index 0000000000..1a4f25206a
--- /dev/null
+++ b/libavcodec/wavpackenc.c
@@ -0,0 +1,2987 @@
+/*
+ * WavPack lossless audio encoder
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#define BITSTREAM_WRITER_LE
+
+#include "libavutil/intreadwrite.h"
+#include "libavutil/opt.h"
+#include "avcodec.h"
+#include "internal.h"
+#include "put_bits.h"
+#include "bytestream.h"
+#include "wavpackenc.h"
+#include "wavpack.h"
+
+#define UPDATE_WEIGHT(weight, delta, source, result) \
+    if (source && result) { \
+        int32_t s = (int32_t) (source ^ result) >> 31; \
+        weight = (delta ^ s) + (weight - s); \
+    }
+
+#define APPLY_WEIGHT_F(weight, sample) (((((sample & 0xffff) * weight) >> 9) + \
+    (((sample & ~0xffff) >> 9) * weight) + 1) >> 1)
+
+#define APPLY_WEIGHT_I(weight, sample) ((weight * sample + 512) >> 10)
+
+#define APPLY_WEIGHT(weight, sample) (sample != (short) sample ? \
+    APPLY_WEIGHT_F(weight, sample) : APPLY_WEIGHT_I (weight, sample))
+
+#define CLEAR(destin) memset(&destin, 0, sizeof(destin));
+
+#define SHIFT_LSB       13
+#define SHIFT_MASK      (0x1FU << SHIFT_LSB)
+
+#define MAG_LSB         18
+#define MAG_MASK        (0x1FU << MAG_LSB)
+
+#define SRATE_LSB       23
+#define SRATE_MASK      (0xFU << SRATE_LSB)
+
+#define EXTRA_TRY_DELTAS     1
+#define EXTRA_ADJUST_DELTAS  2
+#define EXTRA_SORT_FIRST     4
+#define EXTRA_BRANCHES       8
+#define EXTRA_SORT_LAST     16
+
+typedef struct WavPackExtraInfo {
+    struct Decorr dps[MAX_TERMS];
+    int nterms, log_limit, gt16bit;
+    uint32_t best_bits;
+} WavPackExtraInfo;
+
+typedef struct WavPackWords {
+    int pend_data, holding_one, zeros_acc;
+    int holding_zero, pend_count;
+    WvChannel c[2];
+} WavPackWords;
+
+typedef struct WavPackEncodeContext {
+    AVClass *class;
+    AVCodecContext *avctx;
+    PutBitContext pb;
+    int block_samples;
+    int buffer_size;
+    int sample_index;
+    int stereo, stereo_in;
+    int ch_offset;
+
+    int32_t *samples[2];
+    int samples_size[2];
+
+    int32_t *sampleptrs[MAX_TERMS+2][2];
+    int sampleptrs_size[MAX_TERMS+2][2];
+
+    int32_t *temp_buffer[2][2];
+    int temp_buffer_size[2][2];
+
+    int32_t *best_buffer[2];
+    int best_buffer_size[2];
+
+    int32_t *js_left, *js_right;
+    int js_left_size, js_right_size;
+
+    int32_t *orig_l, *orig_r;
+    int orig_l_size, orig_r_size;
+
+    unsigned extra_flags;
+    int optimize_mono;
+    int decorr_filter;
+    int joint;
+    int num_branches;
+
+    uint32_t flags;
+    uint32_t crc_x;
+    WavPackWords w;
+
+    uint8_t int32_sent_bits, int32_zeros, int32_ones, int32_dups;
+    uint8_t float_flags, float_shift, float_max_exp, max_exp;
+    int32_t shifted_ones, shifted_zeros, shifted_both;
+    int32_t false_zeros, neg_zeros, ordata;
+
+    int num_terms, shift, joint_stereo, false_stereo;
+    int num_decorrs, num_passes, best_decorr, mask_decorr;
+    struct Decorr decorr_passes[MAX_TERMS];
+    const WavPackDecorrSpec *decorr_specs;
+    float delta_decay;
+} WavPackEncodeContext;
+
+static av_cold int wavpack_encode_init(AVCodecContext *avctx)
+{
+    WavPackEncodeContext *s = avctx->priv_data;
+
+    s->avctx = avctx;
+
+    if (!avctx->frame_size) {
+        int block_samples;
+        if (!(avctx->sample_rate & 1))
+            block_samples = avctx->sample_rate / 2;
+        else
+            block_samples = avctx->sample_rate;
+
+        while (block_samples * avctx->channels > 150000)
+            block_samples /= 2;
+
+        while (block_samples * avctx->channels < 40000)
+            block_samples *= 2;
+        avctx->frame_size = block_samples;
+    } else if (avctx->frame_size && (avctx->frame_size < 128 ||
+                              avctx->frame_size > WV_MAX_SAMPLES)) {
+        av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n", avctx->frame_size);
+        return AVERROR(EINVAL);
+    }
+
+    if (avctx->compression_level != FF_COMPRESSION_DEFAULT) {
+        if (avctx->compression_level >= 3) {
+            s->decorr_filter = 3;
+            s->num_passes = 9;
+            if      (avctx->compression_level >= 8) {
+                s->num_branches = 4;
+                s->extra_flags = EXTRA_TRY_DELTAS|EXTRA_ADJUST_DELTAS|EXTRA_SORT_FIRST|EXTRA_SORT_LAST|EXTRA_BRANCHES;
+            } else if (avctx->compression_level >= 7) {
+                s->num_branches = 3;
+                s->extra_flags = EXTRA_TRY_DELTAS|EXTRA_ADJUST_DELTAS|EXTRA_SORT_FIRST|EXTRA_BRANCHES;
+            } else if (avctx->compression_level >= 6) {
+                s->num_branches = 2;
+                s->extra_flags = EXTRA_TRY_DELTAS|EXTRA_ADJUST_DELTAS|EXTRA_SORT_FIRST|EXTRA_BRANCHES;
+            } else if (avctx->compression_level >= 5) {
+                s->num_branches = 1;
+                s->extra_flags = EXTRA_TRY_DELTAS|EXTRA_ADJUST_DELTAS|EXTRA_SORT_FIRST|EXTRA_BRANCHES;
+            } else if (avctx->compression_level >= 4) {
+                s->num_branches = 1;
+                s->extra_flags = EXTRA_TRY_DELTAS|EXTRA_ADJUST_DELTAS|EXTRA_BRANCHES;
+            }
+        } else if (avctx->compression_level == 2) {
+            s->decorr_filter = 2;
+            s->num_passes = 4;
+        } else if (avctx->compression_level == 1) {
+            s->decorr_filter = 1;
+            s->num_passes = 2;
+        } else if (avctx->compression_level < 1) {
+            s->decorr_filter = 0;
+            s->num_passes = 0;
+        }
+    }
+
+    s->num_decorrs = decorr_filter_sizes[s->decorr_filter];
+    s->decorr_specs = decorr_filters[s->decorr_filter];
+
+    s->delta_decay = 2.0;
+
+    return 0;
+}
+
+static void shift_mono(int32_t *samples, int nb_samples, int shift)
+{
+    int i;
+    for (i = 0; i < nb_samples; i++)
+        samples[i] >>= shift;
+}
+
+static void shift_stereo(int32_t *left, int32_t *right,
+                         int nb_samples, int shift)
+{
+    int i;
+    for (i = 0; i < nb_samples; i++) {
+        left [i] >>= shift;
+        right[i] >>= shift;
+    }
+}
+
+#define FLOAT_SHIFT_ONES 1
+#define FLOAT_SHIFT_SAME 2
+#define FLOAT_SHIFT_SENT 4
+#define FLOAT_ZEROS_SENT 8
+#define FLOAT_NEG_ZEROS  0x10
+#define FLOAT_EXCEPTIONS 0x20
+
+#define get_mantissa(f)     ((f) & 0x7fffff)
+#define get_exponent(f)     (((f) >> 23) & 0xff)
+#define get_sign(f)         (((f) >> 31) & 0x1)
+
+static void process_float(WavPackEncodeContext *s, int32_t *sample)
+{
+    int32_t shift_count, value, f = *sample;
+
+    if (get_exponent(f) == 255) {
+        s->float_flags |= FLOAT_EXCEPTIONS;
+        value = 0x1000000;
+        shift_count = 0;
+    } else if (get_exponent(f)) {
+        shift_count = s->max_exp - get_exponent(f);
+        value = 0x800000 + get_mantissa(f);
+    } else {
+        shift_count = s->max_exp ? s->max_exp - 1 : 0;
+        value = get_mantissa(f);
+    }
+
+    if (shift_count < 25)
+        value >>= shift_count;
+    else
+        value = 0;
+
+    if (!value) {
+        if (get_exponent(f) || get_mantissa(f))
+            s->false_zeros++;
+        else if (get_sign(f))
+            s->neg_zeros++;
+    } else if (shift_count) {
+        int32_t mask = (1 << shift_count) - 1;
+
+        if (!(get_mantissa(f) & mask))
+            s->shifted_zeros++;
+        else if ((get_mantissa(f) & mask) == mask)
+            s->shifted_ones++;
+        else
+            s->shifted_both++;
+    }
+
+    s->ordata |= value;
+    *sample = get_sign(f) ? -value : value;
+}
+
+static int scan_float(WavPackEncodeContext *s,
+                      int32_t *samples_l, int32_t *samples_r,
+                      int nb_samples)
+{
+    uint32_t crc = 0xffffffffu;
+    int i;
+
+    s->shifted_ones = s->shifted_zeros = s->shifted_both = s->ordata = 0;
+    s->float_shift = s->float_flags = 0;
+    s->false_zeros = s->neg_zeros = 0;
+    s->max_exp = 0;
+
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t f = samples_l[i];
+            crc = crc * 27 + get_mantissa(f) * 9 + get_exponent(f) * 3 + get_sign(f);
+
+            if (get_exponent(f) > s->max_exp && get_exponent(f) < 255)
+                s->max_exp = get_exponent(f);
+        }
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t f;
+
+            f = samples_l[i];
+            crc = crc * 27 + get_mantissa(f) * 9 + get_exponent(f) * 3 + get_sign(f);
+            if (get_exponent(f) > s->max_exp && get_exponent(f) < 255)
+                s->max_exp = get_exponent(f);
+
+            f = samples_r[i];
+            crc = crc * 27 + get_mantissa(f) * 9 + get_exponent(f) * 3 + get_sign(f);
+
+            if (get_exponent(f) > s->max_exp && get_exponent(f) < 255)
+                s->max_exp = get_exponent(f);
+        }
+    }
+
+    s->crc_x = crc;
+
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++)
+            process_float(s, &samples_l[i]);
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            process_float(s, &samples_l[i]);
+            process_float(s, &samples_r[i]);
+        }
+    }
+
+    s->float_max_exp = s->max_exp;
+
+    if (s->shifted_both)
+        s->float_flags |= FLOAT_SHIFT_SENT;
+    else if (s->shifted_ones && !s->shifted_zeros)
+        s->float_flags |= FLOAT_SHIFT_ONES;
+    else if (s->shifted_ones && s->shifted_zeros)
+        s->float_flags |= FLOAT_SHIFT_SAME;
+    else if (s->ordata && !(s->ordata & 1)) {
+        do {
+            s->float_shift++;
+            s->ordata >>= 1;
+        } while (!(s->ordata & 1));
+
+        if (s->flags & WV_MONO_DATA)
+            shift_mono(samples_l, nb_samples, s->float_shift);
+        else
+            shift_stereo(samples_l, samples_r, nb_samples, s->float_shift);
+    }
+
+    s->flags &= ~MAG_MASK;
+
+    while (s->ordata) {
+        s->flags += 1 << MAG_LSB;
+        s->ordata >>= 1;
+    }
+
+    if (s->false_zeros || s->neg_zeros)
+        s->float_flags |= FLOAT_ZEROS_SENT;
+
+    if (s->neg_zeros)
+        s->float_flags |= FLOAT_NEG_ZEROS;
+
+    return s->float_flags & (FLOAT_EXCEPTIONS | FLOAT_ZEROS_SENT |
+                             FLOAT_SHIFT_SENT | FLOAT_SHIFT_SAME);
+}
+
+static void scan_int23(WavPackEncodeContext *s,
+                       int32_t *samples_l, int32_t *samples_r,
+                       int nb_samples)
+{
+    uint32_t magdata = 0, ordata = 0, xordata = 0, anddata = ~0;
+    int i, total_shift = 0;
+
+    s->int32_sent_bits = s->int32_zeros = s->int32_ones = s->int32_dups = 0;
+
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t M = samples_l[i];
+
+            magdata |= (M < 0) ? ~M : M;
+            xordata |= M ^ -(M & 1);
+            anddata &= M;
+            ordata  |= M;
+
+            if ((ordata & 1) && !(anddata & 1) && (xordata & 2))
+                return;
+        }
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t L = samples_l[i];
+            int32_t R = samples_r[i];
+
+            magdata |= (L < 0) ? ~L : L;
+            magdata |= (R < 0) ? ~R : R;
+            xordata |= L ^ -(L & 1);
+            xordata |= R ^ -(R & 1);
+            anddata &= L & R;
+            ordata  |= L | R;
+
+            if ((ordata & 1) && !(anddata & 1) && (xordata & 2))
+                return;
+        }
+    }
+
+    s->flags &= ~MAG_MASK;
+
+    while (magdata) {
+        s->flags += 1 << MAG_LSB;
+        magdata >>= 1;
+    }
+
+    if (!(s->flags & MAG_MASK))
+        return;
+
+    if (!(ordata & 1)) {
+        do {
+            s->flags -= 1 << MAG_LSB;
+            s->int32_zeros++;
+            total_shift++;
+            ordata >>= 1;
+        } while (!(ordata & 1));
+    } else if (anddata & 1) {
+        do {
+            s->flags -= 1 << MAG_LSB;
+            s->int32_ones++;
+            total_shift++;
+            anddata >>= 1;
+        } while (anddata & 1);
+    } else if (!(xordata & 2)) {
+        do {
+            s->flags -= 1 << MAG_LSB;
+            s->int32_dups++;
+            total_shift++;
+            xordata >>= 1;
+        } while (!(xordata & 2));
+    }
+
+    if (total_shift) {
+        s->flags |= WV_INT32_DATA;
+
+        if (s->flags & WV_MONO_DATA)
+            shift_mono(samples_l, nb_samples, total_shift);
+        else
+            shift_stereo(samples_l, samples_r, nb_samples, total_shift);
+    }
+}
+
+static int scan_int32(WavPackEncodeContext *s,
+                      int32_t *samples_l, int32_t *samples_r,
+                      int nb_samples)
+{
+    uint32_t magdata = 0, ordata = 0, xordata = 0, anddata = ~0;
+    uint32_t crc = 0xffffffffu;
+    int i, total_shift = 0;
+
+    s->int32_sent_bits = s->int32_zeros = s->int32_ones = s->int32_dups = 0;
+
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t M = samples_l[i];
+
+            crc = crc * 9 + (M & 0xffff) * 3 + ((M >> 16) & 0xffff);
+            magdata |= (M < 0) ? ~M : M;
+            xordata |= M ^ -(M & 1);
+            anddata &= M;
+            ordata  |= M;
+        }
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t L = samples_l[i];
+            int32_t R = samples_r[i];
+
+            crc = crc * 9 + (L & 0xffff) * 3 + ((L >> 16) & 0xffff);
+            crc = crc * 9 + (R & 0xffff) * 3 + ((R >> 16) & 0xffff);
+            magdata |= (L < 0) ? ~L : L;
+            magdata |= (R < 0) ? ~R : R;
+            xordata |= L ^ -(L & 1);
+            xordata |= R ^ -(R & 1);
+            anddata &= L & R;
+            ordata  |= L | R;
+        }
+    }
+
+    s->crc_x = crc;
+    s->flags &= ~MAG_MASK;
+
+    while (magdata) {
+        s->flags += 1 << MAG_LSB;
+        magdata >>= 1;
+    }
+
+    if (!((s->flags & MAG_MASK) >> MAG_LSB)) {
+        s->flags &= ~WV_INT32_DATA;
+        return 0;
+    }
+
+    if (!(ordata & 1))
+        do {
+            s->flags -= 1 << MAG_LSB;
+            s->int32_zeros++;
+            total_shift++;
+            ordata >>= 1;
+        } while (!(ordata & 1));
+    else if (anddata & 1)
+        do {
+            s->flags -= 1 << MAG_LSB;
+            s->int32_ones++;
+            total_shift++;
+            anddata >>= 1;
+        } while (anddata & 1);
+    else if (!(xordata & 2))
+        do {
+            s->flags -= 1 << MAG_LSB;
+            s->int32_dups++;
+            total_shift++;
+            xordata >>= 1;
+        } while (!(xordata & 2));
+
+    if (((s->flags & MAG_MASK) >> MAG_LSB) > 23) {
+        s->int32_sent_bits = (uint8_t)(((s->flags & MAG_MASK) >> MAG_LSB) - 23);
+        total_shift += s->int32_sent_bits;
+        s->flags &= ~MAG_MASK;
+        s->flags += 23 << MAG_LSB;
+    }
+
+    if (total_shift) {
+        s->flags |= WV_INT32_DATA;
+
+        if (s->flags & WV_MONO_DATA)
+            shift_mono(samples_l, nb_samples, total_shift);
+        else
+            shift_stereo(samples_l, samples_r, nb_samples, total_shift);
+    }
+
+    return s->int32_sent_bits;
+}
+
+static int8_t store_weight(int weight)
+{
+    weight = av_clip(weight, -1024, 1024);
+    if (weight > 0)
+        weight -= (weight + 64) >> 7;
+
+    return (weight + 4) >> 3;
+}
+
+static int restore_weight(int8_t weight)
+{
+    int result;
+
+    if ((result = (int) weight << 3) > 0)
+        result += (result + 64) >> 7;
+
+    return result;
+}
+
+static int log2s(int32_t value)
+{
+    return (value < 0) ? -wp_log2(-value) : wp_log2(value);
+}
+
+static void decorr_mono(int32_t *in_samples, int32_t *out_samples,
+                        int nb_samples, struct Decorr *dpp, int dir)
+{
+    int m = 0, i;
+
+    dpp->sumA = 0;
+
+    if (dir < 0) {
+        out_samples += (nb_samples - 1);
+        in_samples  += (nb_samples - 1);
+    }
+
+    dpp->weightA = restore_weight(store_weight(dpp->weightA));
+
+    for (i = 0; i < MAX_TERM; i++)
+        dpp->samplesA[i] = wp_exp2(log2s(dpp->samplesA[i]));
+
+    if (dpp->value > MAX_TERM) {
+        while (nb_samples--) {
+            int32_t left, sam_A;
+
+            sam_A = ((3 - (dpp->value & 1)) * dpp->samplesA[0] - dpp->samplesA[1]) >> !(dpp->value & 1);
+
+            dpp->samplesA[1] = dpp->samplesA[0];
+            dpp->samplesA[0] = left = in_samples[0];
+
+            left -= APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam_A, left);
+            dpp->sumA += dpp->weightA;
+            out_samples[0] = left;
+            in_samples += dir;
+            out_samples += dir;
+        }
+    } else if (dpp->value > 0) {
+        while (nb_samples--) {
+            int k = (m + dpp->value) & (MAX_TERM - 1);
+            int32_t left, sam_A;
+
+            sam_A = dpp->samplesA[m];
+            dpp->samplesA[k] = left = in_samples[0];
+            m = (m + 1) & (MAX_TERM - 1);
+
+            left -= APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam_A, left);
+            dpp->sumA += dpp->weightA;
+            out_samples[0] = left;
+            in_samples += dir;
+            out_samples += dir;
+        }
+    }
+
+    if (m && dpp->value > 0 && dpp->value <= MAX_TERM) {
+        int32_t temp_A[MAX_TERM];
+
+        memcpy(temp_A, dpp->samplesA, sizeof(dpp->samplesA));
+
+        for (i = 0; i < MAX_TERM; i++) {
+            dpp->samplesA[i] = temp_A[m];
+            m = (m + 1) & (MAX_TERM - 1);
+        }
+    }
+}
+
+static void reverse_mono_decorr(struct Decorr *dpp)
+{
+    if (dpp->value > MAX_TERM) {
+        int32_t sam_A;
+
+        if (dpp->value & 1)
+            sam_A = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+        else
+            sam_A = (3 * dpp->samplesA[0] - dpp->samplesA[1]) >> 1;
+
+        dpp->samplesA[1] = dpp->samplesA[0];
+        dpp->samplesA[0] = sam_A;
+
+        if (dpp->value & 1)
+            sam_A = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+        else
+            sam_A = (3 * dpp->samplesA[0] - dpp->samplesA[1]) >> 1;
+
+        dpp->samplesA[1] = sam_A;
+    } else if (dpp->value > 1) {
+        int i, j, k;
+
+        for (i = 0, j = dpp->value - 1, k = 0; k < dpp->value / 2; i++, j--, k++) {
+            i &= (MAX_TERM - 1);
+            j &= (MAX_TERM - 1);
+            dpp->samplesA[i] ^= dpp->samplesA[j];
+            dpp->samplesA[j] ^= dpp->samplesA[i];
+            dpp->samplesA[i] ^= dpp->samplesA[j];
+        }
+    }
+}
+
+static uint32_t log2sample(uint32_t v, int limit, uint32_t *result)
+{
+    uint32_t dbits;
+
+    if ((v += v >> 9) < (1 << 8)) {
+        dbits = nbits_table[v];
+        result += (dbits << 8) + wp_log2_table[(v << (9 - dbits)) & 0xff];
+    } else {
+        if (v < (1L << 16))
+            dbits = nbits_table[v >> 8] + 8;
+        else if (v < (1L << 24))
+            dbits = nbits_table[v >> 16] + 16;
+        else
+            dbits = nbits_table[v >> 24] + 24;
+
+        result += dbits = (dbits << 8) + wp_log2_table[(v >> (dbits - 9)) & 0xff];
+
+        if (limit && dbits >= limit)
+            return 1;
+    }
+
+    return 0;
+}
+
+static uint32_t log2mono(int32_t *samples, int nb_samples, int limit)
+{
+    uint32_t result = 0;
+    while (nb_samples--) {
+        if (log2sample(abs(*samples++), limit, &result))
+            return UINT32_MAX;
+    }
+    return result;
+}
+
+static uint32_t log2stereo(int32_t *samples_l, int32_t *samples_r,
+                           int nb_samples, int limit)
+{
+    uint32_t result = 0;
+    while (nb_samples--) {
+        if (log2sample(abs(*samples_l++), limit, &result) ||
+            log2sample(abs(*samples_r++), limit, &result))
+            return UINT32_MAX;
+    }
+    return result;
+}
+
+static void decorr_mono_buffer(int32_t *samples, int32_t *outsamples,
+                               int nb_samples, struct Decorr *dpp,
+                               int tindex)
+{
+    struct Decorr dp, *dppi = dpp + tindex;
+    int delta = dppi->delta, pre_delta, term = dppi->value;
+
+    if (delta == 7)
+        pre_delta = 7;
+    else if (delta < 2)
+        pre_delta = 3;
+    else
+        pre_delta = delta + 1;
+
+    CLEAR(dp);
+    dp.value = term;
+    dp.delta = pre_delta;
+    decorr_mono(samples, outsamples, FFMIN(2048, nb_samples), &dp, -1);
+    dp.delta = delta;
+
+    if (tindex == 0)
+        reverse_mono_decorr(&dp);
+    else
+        CLEAR(dp.samplesA);
+
+    memcpy(dppi->samplesA, dp.samplesA, sizeof(dp.samplesA));
+    dppi->weightA = dp.weightA;
+
+    if (delta == 0) {
+        dp.delta = 1;
+        decorr_mono(samples, outsamples, nb_samples, &dp, 1);
+        dp.delta = 0;
+        memcpy(dp.samplesA, dppi->samplesA, sizeof(dp.samplesA));
+        dppi->weightA = dp.weightA = dp.sumA / nb_samples;
+    }
+
+    decorr_mono(samples, outsamples, nb_samples, &dp, 1);
+}
+
+static void recurse_mono(WavPackEncodeContext *s, WavPackExtraInfo *info,
+                         int depth, int delta, uint32_t input_bits)
+{
+    int term, branches = s->num_branches - depth;
+    int32_t *samples, *outsamples;
+    uint32_t term_bits[22], bits;
+
+    if (branches < 1 || depth + 1 == info->nterms)
+        branches = 1;
+
+    CLEAR(term_bits);
+    samples = s->sampleptrs[depth][0];
+    outsamples = s->sampleptrs[depth + 1][0];
+
+    for (term = 1; term <= 18; term++) {
+        if (term == 17 && branches == 1 && depth + 1 < info->nterms)
+            continue;
+
+        if (term > 8 && term < 17)
+            continue;
+
+        if (!s->extra_flags && (term > 4 && term < 17))
+            continue;
+
+        info->dps[depth].value = term;
+        info->dps[depth].delta = delta;
+        decorr_mono_buffer(samples, outsamples, s->block_samples, info->dps, depth);
+        bits = log2mono(outsamples, s->block_samples, info->log_limit);
+
+        if (bits < info->best_bits) {
+            info->best_bits = bits;
+            CLEAR(s->decorr_passes);
+            memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * (depth + 1));
+            memcpy(s->sampleptrs[info->nterms + 1][0],
+                   s->sampleptrs[depth + 1][0], s->block_samples * 4);
+        }
+
+        term_bits[term + 3] = bits;
+    }
+
+    while (depth + 1 < info->nterms && branches--) {
+        uint32_t local_best_bits = input_bits;
+        int best_term = 0, i;
+
+        for (i = 0; i < 22; i++)
+            if (term_bits[i] && term_bits[i] < local_best_bits) {
+                local_best_bits = term_bits[i];
+                best_term = i - 3;
+            }
+
+        if (!best_term)
+            break;
+
+        term_bits[best_term + 3] = 0;
+
+        info->dps[depth].value = best_term;
+        info->dps[depth].delta = delta;
+        decorr_mono_buffer(samples, outsamples, s->block_samples, info->dps, depth);
+
+        recurse_mono(s, info, depth + 1, delta, local_best_bits);
+    }
+}
+
+static void sort_mono(WavPackEncodeContext *s, WavPackExtraInfo *info)
+{
+    int reversed = 1;
+    uint32_t bits;
+
+    while (reversed) {
+        int ri, i;
+
+        memcpy(info->dps, s->decorr_passes, sizeof(s->decorr_passes));
+        reversed = 0;
+
+        for (ri = 0; ri < info->nterms && s->decorr_passes[ri].value; ri++) {
+
+            if (ri + 1 >= info->nterms || !s->decorr_passes[ri+1].value)
+                break;
+
+            if (s->decorr_passes[ri].value == s->decorr_passes[ri+1].value) {
+                decorr_mono_buffer(s->sampleptrs[ri][0], s->sampleptrs[ri+1][0],
+                                   s->block_samples, info->dps, ri);
+                continue;
+            }
+
+            info->dps[ri  ] = s->decorr_passes[ri+1];
+            info->dps[ri+1] = s->decorr_passes[ri  ];
+
+            for (i = ri; i < info->nterms && s->decorr_passes[i].value; i++)
+                decorr_mono_buffer(s->sampleptrs[i][0], s->sampleptrs[i+1][0],
+                                   s->block_samples, info->dps, i);
+
+            bits = log2mono(s->sampleptrs[i][0], s->block_samples, info->log_limit);
+            if (bits < info->best_bits) {
+                reversed = 1;
+                info->best_bits = bits;
+                CLEAR(s->decorr_passes);
+                memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * i);
+                memcpy(s->sampleptrs[info->nterms + 1][0], s->sampleptrs[i][0],
+                       s->block_samples * 4);
+            } else {
+                info->dps[ri  ] = s->decorr_passes[ri];
+                info->dps[ri+1] = s->decorr_passes[ri+1];
+                decorr_mono_buffer(s->sampleptrs[ri][0], s->sampleptrs[ri+1][0],
+                                   s->block_samples, info->dps, ri);
+            }
+        }
+    }
+}
+
+static void delta_mono(WavPackEncodeContext *s, WavPackExtraInfo *info)
+{
+    int lower = 0, delta, d;
+    uint32_t bits;
+
+    if (!s->decorr_passes[0].value)
+        return;
+    delta = s->decorr_passes[0].delta;
+
+    for (d = delta - 1; d >= 0; d--) {
+        int i;
+
+        for (i = 0; i < info->nterms && s->decorr_passes[i].value; i++) {
+            info->dps[i].value = s->decorr_passes[i].value;
+            info->dps[i].delta = d;
+            decorr_mono_buffer(s->sampleptrs[i][0], s->sampleptrs[i+1][0],
+                               s->block_samples, info->dps, i);
+        }
+
+        bits = log2mono(s->sampleptrs[i][0], s->block_samples, info->log_limit);
+        if (bits >= info->best_bits)
+            break;
+
+        lower = 1;
+        info->best_bits = bits;
+        CLEAR(s->decorr_passes);
+        memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * i);
+        memcpy(s->sampleptrs[info->nterms + 1][0],  s->sampleptrs[i][0],
+               s->block_samples * 4);
+    }
+
+    for (d = delta + 1; !lower && d <= 7; d++) {
+        int i;
+
+        for (i = 0; i < info->nterms && s->decorr_passes[i].value; i++) {
+            info->dps[i].value = s->decorr_passes[i].value;
+            info->dps[i].delta = d;
+            decorr_mono_buffer(s->sampleptrs[i][0], s->sampleptrs[i+1][0],
+                               s->block_samples, info->dps, i);
+        }
+
+        bits = log2mono(s->sampleptrs[i][0], s->block_samples, info->log_limit);
+        if (bits >= info->best_bits)
+            break;
+
+        info->best_bits = bits;
+        CLEAR(s->decorr_passes);
+        memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * i);
+        memcpy(s->sampleptrs[info->nterms + 1][0], s->sampleptrs[i][0],
+               s->block_samples * 4);
+    }
+}
+
+static int allocate_buffers2(WavPackEncodeContext *s, int nterms)
+{
+    int i;
+
+    for (i = 0; i < nterms + 2; i++) {
+        av_fast_padded_malloc(&s->sampleptrs[i][0], &s->sampleptrs_size[i][0],
+                              s->block_samples * 4);
+        if (!s->sampleptrs[i][0])
+            return AVERROR(ENOMEM);
+        if (!(s->flags & WV_MONO_DATA)) {
+            av_fast_padded_malloc(&s->sampleptrs[i][1], &s->sampleptrs_size[i][1],
+                                  s->block_samples * 4);
+            if (!s->sampleptrs[i][1])
+                return AVERROR(ENOMEM);
+        }
+    }
+
+    return 0;
+}
+
+static int allocate_buffers(WavPackEncodeContext *s)
+{
+    int i;
+
+    for (i = 0; i < 2; i++) {
+        av_fast_padded_malloc(&s->best_buffer[0], &s->best_buffer_size[0],
+                              s->block_samples * 4);
+        if (!s->best_buffer[0])
+            return AVERROR(ENOMEM);
+
+        av_fast_padded_malloc(&s->temp_buffer[i][0], &s->temp_buffer_size[i][0],
+                              s->block_samples * 4);
+        if (!s->temp_buffer[i][0])
+            return AVERROR(ENOMEM);
+        if (!(s->flags & WV_MONO_DATA)) {
+            av_fast_padded_malloc(&s->best_buffer[1], &s->best_buffer_size[1],
+                                  s->block_samples * 4);
+            if (!s->best_buffer[1])
+                return AVERROR(ENOMEM);
+
+            av_fast_padded_malloc(&s->temp_buffer[i][1], &s->temp_buffer_size[i][1],
+                                  s->block_samples * 4);
+            if (!s->temp_buffer[i][1])
+                return AVERROR(ENOMEM);
+        }
+    }
+
+    return 0;
+}
+
+static void analyze_mono(WavPackEncodeContext *s, int32_t *samples, int do_samples)
+{
+    WavPackExtraInfo info;
+    int i;
+
+    info.log_limit = (((s->flags & MAG_MASK) >> MAG_LSB) + 4) * 256;
+    info.log_limit = FFMIN(6912, info.log_limit);
+
+    info.nterms = s->num_terms;
+
+    if (allocate_buffers2(s, s->num_terms))
+        return;
+
+    memcpy(info.dps, s->decorr_passes, sizeof(info.dps));
+    memcpy(s->sampleptrs[0][0], samples, s->block_samples * 4);
+
+    for (i = 0; i < info.nterms && info.dps[i].value; i++)
+        decorr_mono(s->sampleptrs[i][0], s->sampleptrs[i + 1][0],
+                    s->block_samples, info.dps + i, 1);
+
+    info.best_bits = log2mono(s->sampleptrs[info.nterms][0], s->block_samples, 0) * 1;
+    memcpy(s->sampleptrs[info.nterms + 1][0], s->sampleptrs[i][0], s->block_samples * 4);
+
+    if (s->extra_flags & EXTRA_BRANCHES)
+        recurse_mono(s, &info, 0, (int) floor(s->delta_decay + 0.5),
+                     log2mono(s->sampleptrs[0][0], s->block_samples, 0));
+
+    if (s->extra_flags & EXTRA_SORT_FIRST)
+        sort_mono(s, &info);
+
+    if (s->extra_flags & EXTRA_TRY_DELTAS) {
+        delta_mono(s, &info);
+
+        if ((s->extra_flags & EXTRA_ADJUST_DELTAS) && s->decorr_passes[0].value)
+            s->delta_decay = (float)((s->delta_decay * 2.0 + s->decorr_passes[0].delta) / 3.0);
+        else
+            s->delta_decay = 2.0;
+    }
+
+    if (s->extra_flags & EXTRA_SORT_LAST)
+        sort_mono(s, &info);
+
+    if (do_samples)
+        memcpy(samples, s->sampleptrs[info.nterms + 1][0], s->block_samples * 4);
+
+    for (i = 0; i < info.nterms; i++)
+        if (!s->decorr_passes[i].value)
+            break;
+
+    s->num_terms = i;
+}
+
+static void scan_word(WavPackEncodeContext *s, WvChannel *c,
+                      int32_t *samples, int nb_samples, int dir)
+{
+    if (dir < 0)
+        samples += nb_samples - 1;
+
+    while (nb_samples--) {
+        uint32_t low, value = labs(samples[0]);
+
+        if (value < GET_MED(0)) {
+            DEC_MED(0);
+        } else {
+            low = GET_MED(0);
+            INC_MED(0);
+
+            if (value - low < GET_MED(1)) {
+                DEC_MED(1);
+            } else {
+                low += GET_MED(1);
+                INC_MED(1);
+
+                if (value - low < GET_MED(2)) {
+                    DEC_MED(2);
+                } else {
+                    INC_MED(2);
+                }
+            }
+        }
+        samples += dir;
+    }
+}
+
+static int wv_mono(WavPackEncodeContext *s, int32_t *samples,
+                   int no_history, int do_samples)
+{
+    struct Decorr temp_decorr_pass, save_decorr_passes[MAX_TERMS] = {{0}};
+    int nb_samples = s->block_samples;
+    int buf_size = sizeof(int32_t) * nb_samples;
+    uint32_t best_size = UINT32_MAX, size;
+    int log_limit, pi, i, ret;
+
+    for (i = 0; i < nb_samples; i++)
+        if (samples[i])
+            break;
+
+    if (i == nb_samples) {
+        CLEAR(s->decorr_passes);
+        CLEAR(s->w);
+        s->num_terms = 0;
+        return 0;
+    }
+
+    log_limit = (((s->flags & MAG_MASK) >> MAG_LSB) + 4) * 256;
+    log_limit = FFMIN(6912, log_limit);
+
+    if ((ret = allocate_buffers(s)) < 0)
+        return ret;
+
+    if (no_history || s->num_passes >= 7)
+        s->best_decorr = s->mask_decorr = 0;
+
+    for (pi = 0; pi < s->num_passes;) {
+        const WavPackDecorrSpec *wpds;
+        int nterms, c, j;
+
+        if (!pi) {
+            c = s->best_decorr;
+        } else {
+            if (s->mask_decorr == 0)
+                c = 0;
+            else
+                c = (s->best_decorr & (s->mask_decorr - 1)) | s->mask_decorr;
+
+            if (c == s->best_decorr) {
+                s->mask_decorr = s->mask_decorr ? ((s->mask_decorr << 1) & (s->num_decorrs - 1)) : 1;
+                continue;
+            }
+        }
+
+        wpds = &s->decorr_specs[c];
+        nterms = decorr_filter_nterms[s->decorr_filter];
+
+        while (1) {
+        memcpy(s->temp_buffer[0][0], samples, buf_size);
+        CLEAR(save_decorr_passes);
+
+        for (j = 0; j < nterms; j++) {
+            CLEAR(temp_decorr_pass);
+            temp_decorr_pass.delta = wpds->delta;
+            temp_decorr_pass.value = wpds->terms[j];
+
+            if (temp_decorr_pass.value < 0)
+                temp_decorr_pass.value = 1;
+
+            decorr_mono(s->temp_buffer[j&1][0], s->temp_buffer[~j&1][0],
+                        FFMIN(nb_samples, 2048), &temp_decorr_pass, -1);
+
+            if (j) {
+                CLEAR(temp_decorr_pass.samplesA);
+            } else {
+                reverse_mono_decorr(&temp_decorr_pass);
+            }
+
+            memcpy(save_decorr_passes + j, &temp_decorr_pass, sizeof(struct Decorr));
+            decorr_mono(s->temp_buffer[j&1][0], s->temp_buffer[~j&1][0],
+                        nb_samples, &temp_decorr_pass, 1);
+        }
+
+        size = log2mono(s->temp_buffer[j&1][0], nb_samples, log_limit);
+        if (size != UINT32_MAX || !nterms)
+            break;
+        nterms >>= 1;
+        }
+
+        if (size < best_size) {
+            memcpy(s->best_buffer[0], s->temp_buffer[j&1][0], buf_size);
+            memcpy(s->decorr_passes, save_decorr_passes, sizeof(struct Decorr) * MAX_TERMS);
+            s->num_terms = nterms;
+            s->best_decorr = c;
+            best_size = size;
+        }
+
+        if (pi++)
+            s->mask_decorr = s->mask_decorr ? ((s->mask_decorr << 1) & (s->num_decorrs - 1)) : 1;
+    }
+
+    if (s->extra_flags)
+        analyze_mono(s, samples, do_samples);
+    else if (do_samples)
+        memcpy(samples, s->best_buffer[0], buf_size);
+
+    if (no_history || s->extra_flags) {
+        CLEAR(s->w);
+        scan_word(s, &s->w.c[0], s->best_buffer[0], nb_samples, -1);
+    }
+    return 0;
+}
+
+static void decorr_stereo(int32_t *in_left, int32_t *in_right,
+                          int32_t *out_left, int32_t *out_right,
+                          int nb_samples, struct Decorr *dpp, int dir)
+{
+    int m = 0, i;
+
+    dpp->sumA = dpp->sumB = 0;
+
+    if (dir < 0) {
+        out_left  += nb_samples - 1;
+        out_right += nb_samples - 1;
+        in_left   += nb_samples - 1;
+        in_right  += nb_samples - 1;
+    }
+
+    dpp->weightA = restore_weight(store_weight(dpp->weightA));
+    dpp->weightB = restore_weight(store_weight(dpp->weightB));
+
+    for (i = 0; i < MAX_TERM; i++) {
+        dpp->samplesA[i] = wp_exp2(log2s(dpp->samplesA[i]));
+        dpp->samplesB[i] = wp_exp2(log2s(dpp->samplesB[i]));
+    }
+
+    switch (dpp->value) {
+    case 2:
+        while (nb_samples--) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[0];
+            dpp->samplesA[0] = dpp->samplesA[1];
+            out_left[0] = tmp = (dpp->samplesA[1] = in_left[0]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+            dpp->sumA += dpp->weightA;
+
+            sam = dpp->samplesB[0];
+            dpp->samplesB[0] = dpp->samplesB[1];
+            out_right[0] = tmp = (dpp->samplesB[1] = in_right[0]) - APPLY_WEIGHT(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+            dpp->sumB += dpp->weightB;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+        }
+        break;
+    case 17:
+        while (nb_samples--) {
+            int32_t sam, tmp;
+
+            sam = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+            dpp->samplesA[1] = dpp->samplesA[0];
+            out_left[0] = tmp = (dpp->samplesA[0] = in_left[0]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+            dpp->sumA += dpp->weightA;
+
+            sam = 2 * dpp->samplesB[0] - dpp->samplesB[1];
+            dpp->samplesB[1] = dpp->samplesB[0];
+            out_right[0] = tmp = (dpp->samplesB[0] = in_right[0]) - APPLY_WEIGHT (dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+            dpp->sumB += dpp->weightB;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+        }
+        break;
+    case 18:
+        while (nb_samples--) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[0] + ((dpp->samplesA[0] - dpp->samplesA[1]) >> 1);
+            dpp->samplesA[1] = dpp->samplesA[0];
+            out_left[0] = tmp = (dpp->samplesA[0] = in_left[0]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+            dpp->sumA += dpp->weightA;
+
+            sam = dpp->samplesB[0] + ((dpp->samplesB[0] - dpp->samplesB[1]) >> 1);
+            dpp->samplesB[1] = dpp->samplesB[0];
+            out_right[0] = tmp = (dpp->samplesB[0] = in_right[0]) - APPLY_WEIGHT(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+            dpp->sumB += dpp->weightB;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+        }
+        break;
+    default: {
+        int k = dpp->value & (MAX_TERM - 1);
+
+        while (nb_samples--) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[m];
+            out_left[0] = tmp = (dpp->samplesA[k] = in_left[0]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+            dpp->sumA += dpp->weightA;
+
+            sam = dpp->samplesB[m];
+            out_right[0] = tmp = (dpp->samplesB[k] = in_right[0]) - APPLY_WEIGHT(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+            dpp->sumB += dpp->weightB;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+            m = (m + 1) & (MAX_TERM - 1);
+            k = (k + 1) & (MAX_TERM - 1);
+        }
+
+        if (m) {
+            int32_t temp_A[MAX_TERM], temp_B[MAX_TERM];
+            int k;
+
+            memcpy(temp_A, dpp->samplesA, sizeof(dpp->samplesA));
+            memcpy(temp_B, dpp->samplesB, sizeof(dpp->samplesB));
+
+            for (k = 0; k < MAX_TERM; k++) {
+                dpp->samplesA[k] = temp_A[m];
+                dpp->samplesB[k] = temp_B[m];
+                m = (m + 1) & (MAX_TERM - 1);
+            }
+        }
+        break;
+        }
+    case -1:
+        while (nb_samples--) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            out_left[0] = tmp = (sam_B = in_left[0]) - APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+            dpp->sumA += dpp->weightA;
+
+            out_right[0] = tmp = (dpp->samplesA[0] = in_right[0]) - APPLY_WEIGHT(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+            dpp->sumB += dpp->weightB;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+        }
+        break;
+    case -2:
+        while (nb_samples--) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_B = dpp->samplesB[0];
+            out_right[0] = tmp = (sam_A = in_right[0]) - APPLY_WEIGHT(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+            dpp->sumB += dpp->weightB;
+
+            out_left[0] = tmp = (dpp->samplesB[0] = in_left[0]) - APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+            dpp->sumA += dpp->weightA;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+        }
+        break;
+    case -3:
+        while (nb_samples--) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            sam_B = dpp->samplesB[0];
+
+            dpp->samplesA[0] = tmp = in_right[0];
+            out_right[0] = tmp -= APPLY_WEIGHT(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+            dpp->sumB += dpp->weightB;
+
+            dpp->samplesB[0] = tmp = in_left[0];
+            out_left[0] = tmp -= APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+            dpp->sumA += dpp->weightA;
+
+            in_left   += dir;
+            out_left  += dir;
+            in_right  += dir;
+            out_right += dir;
+        }
+        break;
+    }
+}
+
+static void reverse_decorr(struct Decorr *dpp)
+{
+    if (dpp->value > MAX_TERM) {
+        int32_t sam_A, sam_B;
+
+        if (dpp->value & 1) {
+            sam_A = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+            sam_B = 2 * dpp->samplesB[0] - dpp->samplesB[1];
+        } else {
+            sam_A = (3 * dpp->samplesA[0] - dpp->samplesA[1]) >> 1;
+            sam_B = (3 * dpp->samplesB[0] - dpp->samplesB[1]) >> 1;
+        }
+
+        dpp->samplesA[1] = dpp->samplesA[0];
+        dpp->samplesB[1] = dpp->samplesB[0];
+        dpp->samplesA[0] = sam_A;
+        dpp->samplesB[0] = sam_B;
+
+        if (dpp->value & 1) {
+            sam_A = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+            sam_B = 2 * dpp->samplesB[0] - dpp->samplesB[1];
+        } else {
+            sam_A = (3 * dpp->samplesA[0] - dpp->samplesA[1]) >> 1;
+            sam_B = (3 * dpp->samplesB[0] - dpp->samplesB[1]) >> 1;
+        }
+
+        dpp->samplesA[1] = sam_A;
+        dpp->samplesB[1] = sam_B;
+    } else if (dpp->value > 1) {
+        int i, j, k;
+
+        for (i = 0, j = dpp->value - 1, k = 0; k < dpp->value / 2; i++, j--, k++) {
+            i &= (MAX_TERM - 1);
+            j &= (MAX_TERM - 1);
+            dpp->samplesA[i] ^= dpp->samplesA[j];
+            dpp->samplesA[j] ^= dpp->samplesA[i];
+            dpp->samplesA[i] ^= dpp->samplesA[j];
+            dpp->samplesB[i] ^= dpp->samplesB[j];
+            dpp->samplesB[j] ^= dpp->samplesB[i];
+            dpp->samplesB[i] ^= dpp->samplesB[j];
+        }
+    }
+}
+
+static void decorr_stereo_quick(int32_t *in_left,  int32_t *in_right,
+                                int32_t *out_left, int32_t *out_right,
+                                int nb_samples, struct Decorr *dpp)
+{
+    int m = 0, i;
+
+    dpp->weightA = restore_weight(store_weight(dpp->weightA));
+    dpp->weightB = restore_weight(store_weight(dpp->weightB));
+
+    for (i = 0; i < MAX_TERM; i++) {
+        dpp->samplesA[i] = wp_exp2(log2s(dpp->samplesA[i]));
+        dpp->samplesB[i] = wp_exp2(log2s(dpp->samplesB[i]));
+    }
+
+    switch (dpp->value) {
+    case 2:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[0];
+            dpp->samplesA[0] = dpp->samplesA[1];
+            out_left[i] = tmp = (dpp->samplesA[1] = in_left[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[0];
+            dpp->samplesB[0] = dpp->samplesB[1];
+            out_right[i] = tmp = (dpp->samplesB[1] = in_right[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    case 17:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+            dpp->samplesA[1] = dpp->samplesA[0];
+            out_left[i] = tmp = (dpp->samplesA[0] = in_left[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = 2 * dpp->samplesB[0] - dpp->samplesB[1];
+            dpp->samplesB[1] = dpp->samplesB[0];
+            out_right[i] = tmp = (dpp->samplesB[0] = in_right[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    case 18:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[0] + ((dpp->samplesA[0] - dpp->samplesA[1]) >> 1);
+            dpp->samplesA[1] = dpp->samplesA[0];
+            out_left[i] = tmp = (dpp->samplesA[0] = in_left[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[0] + ((dpp->samplesB[0] - dpp->samplesB[1]) >> 1);
+            dpp->samplesB[1] = dpp->samplesB[0];
+            out_right[i] = tmp = (dpp->samplesB[0] = in_right[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    default: {
+        int k = dpp->value & (MAX_TERM - 1);
+
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[m];
+            out_left[i] = tmp = (dpp->samplesA[k] = in_left[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[m];
+            out_right[i] = tmp = (dpp->samplesB[k] = in_right[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+
+            m = (m + 1) & (MAX_TERM - 1);
+            k = (k + 1) & (MAX_TERM - 1);
+        }
+
+        if (m) {
+            int32_t temp_A[MAX_TERM], temp_B[MAX_TERM];
+            int k;
+
+            memcpy(temp_A, dpp->samplesA, sizeof(dpp->samplesA));
+            memcpy(temp_B, dpp->samplesB, sizeof(dpp->samplesB));
+
+            for (k = 0; k < MAX_TERM; k++) {
+                dpp->samplesA[k] = temp_A[m];
+                dpp->samplesB[k] = temp_B[m];
+                m = (m + 1) & (MAX_TERM - 1);
+            }
+        }
+        break;
+    }
+    case -1:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            out_left[i] = tmp = (sam_B = in_left[i]) - APPLY_WEIGHT_I(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+
+            out_right[i] = tmp = (dpp->samplesA[0] = in_right[i]) - APPLY_WEIGHT_I(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+        }
+        break;
+    case -2:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_B = dpp->samplesB[0];
+            out_right[i] = tmp = (sam_A = in_right[i]) - APPLY_WEIGHT_I(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+
+            out_left[i] = tmp = (dpp->samplesB[0] = in_left[i]) - APPLY_WEIGHT_I(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+        }
+        break;
+    case -3:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            sam_B = dpp->samplesB[0];
+
+            dpp->samplesA[0] = tmp = in_right[i];
+            out_right[i] = tmp -= APPLY_WEIGHT_I(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+
+            dpp->samplesB[0] = tmp = in_left[i];
+            out_left[i] = tmp -= APPLY_WEIGHT_I(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+        }
+        break;
+    }
+}
+
+static void decorr_stereo_buffer(WavPackExtraInfo *info,
+                                 int32_t *in_left,  int32_t *in_right,
+                                 int32_t *out_left, int32_t *out_right,
+                                 int nb_samples, int tindex)
+{
+    struct Decorr dp = {0}, *dppi = info->dps + tindex;
+    int delta = dppi->delta, pre_delta;
+    int term = dppi->value;
+
+    if (delta == 7)
+        pre_delta = 7;
+    else if (delta < 2)
+        pre_delta = 3;
+    else
+        pre_delta = delta + 1;
+
+    dp.value = term;
+    dp.delta = pre_delta;
+    decorr_stereo(in_left, in_right, out_left, out_right,
+                  FFMIN(2048, nb_samples), &dp, -1);
+    dp.delta = delta;
+
+    if (tindex == 0) {
+        reverse_decorr(&dp);
+    } else {
+        CLEAR(dp.samplesA);
+        CLEAR(dp.samplesB);
+    }
+
+    memcpy(dppi->samplesA, dp.samplesA, sizeof(dp.samplesA));
+    memcpy(dppi->samplesB, dp.samplesB, sizeof(dp.samplesB));
+    dppi->weightA = dp.weightA;
+    dppi->weightB = dp.weightB;
+
+    if (delta == 0) {
+        dp.delta = 1;
+        decorr_stereo(in_left, in_right, out_left, out_right, nb_samples, &dp, 1);
+        dp.delta = 0;
+        memcpy(dp.samplesA, dppi->samplesA, sizeof(dp.samplesA));
+        memcpy(dp.samplesB, dppi->samplesB, sizeof(dp.samplesB));
+        dppi->weightA = dp.weightA = dp.sumA / nb_samples;
+        dppi->weightB = dp.weightB = dp.sumB / nb_samples;
+    }
+
+    if (info->gt16bit)
+        decorr_stereo(in_left, in_right, out_left, out_right,
+                           nb_samples, &dp, 1);
+    else
+        decorr_stereo_quick(in_left, in_right, out_left, out_right,
+                            nb_samples, &dp);
+}
+
+static void sort_stereo(WavPackEncodeContext *s, WavPackExtraInfo *info)
+{
+    int reversed = 1;
+    uint32_t bits;
+
+    while (reversed) {
+        int ri, i;
+
+        memcpy(info->dps, s->decorr_passes, sizeof(s->decorr_passes));
+        reversed = 0;
+
+        for (ri = 0; ri < info->nterms && s->decorr_passes[ri].value; ri++) {
+
+            if (ri + 1 >= info->nterms || !s->decorr_passes[ri+1].value)
+                break;
+
+            if (s->decorr_passes[ri].value == s->decorr_passes[ri+1].value) {
+                decorr_stereo_buffer(info,
+                                     s->sampleptrs[ri  ][0], s->sampleptrs[ri  ][1],
+                                     s->sampleptrs[ri+1][0], s->sampleptrs[ri+1][1],
+                                     s->block_samples, ri);
+                continue;
+            }
+
+            info->dps[ri  ] = s->decorr_passes[ri+1];
+            info->dps[ri+1] = s->decorr_passes[ri  ];
+
+            for (i = ri; i < info->nterms && s->decorr_passes[i].value; i++)
+                decorr_stereo_buffer(info,
+                                     s->sampleptrs[i  ][0], s->sampleptrs[i  ][1],
+                                     s->sampleptrs[i+1][0], s->sampleptrs[i+1][1],
+                                     s->block_samples, i);
+
+            bits = log2stereo(s->sampleptrs[i][0], s->sampleptrs[i][1],
+                              s->block_samples, info->log_limit);
+
+            if (bits < info->best_bits) {
+                reversed = 1;
+                info->best_bits = bits;
+                CLEAR(s->decorr_passes);
+                memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * i);
+                memcpy(s->sampleptrs[info->nterms + 1][0],
+                       s->sampleptrs[i][0], s->block_samples * 4);
+                memcpy(s->sampleptrs[info->nterms + 1][1],
+                       s->sampleptrs[i][1], s->block_samples * 4);
+            } else {
+                info->dps[ri  ] = s->decorr_passes[ri  ];
+                info->dps[ri+1] = s->decorr_passes[ri+1];
+                decorr_stereo_buffer(info,
+                                     s->sampleptrs[ri  ][0], s->sampleptrs[ri  ][1],
+                                     s->sampleptrs[ri+1][0], s->sampleptrs[ri+1][1],
+                                     s->block_samples, ri);
+            }
+        }
+    }
+}
+
+static void delta_stereo(WavPackEncodeContext *s, WavPackExtraInfo *info)
+{
+    int lower = 0, delta, d, i;
+    uint32_t bits;
+
+    if (!s->decorr_passes[0].value)
+        return;
+    delta = s->decorr_passes[0].delta;
+
+    for (d = delta - 1; d >= 0; d--) {
+        for (i = 0; i < info->nterms && s->decorr_passes[i].value; i++) {
+            info->dps[i].value = s->decorr_passes[i].value;
+            info->dps[i].delta = d;
+            decorr_stereo_buffer(info,
+                                 s->sampleptrs[i  ][0], s->sampleptrs[i  ][1],
+                                 s->sampleptrs[i+1][0], s->sampleptrs[i+1][1],
+                                 s->block_samples, i);
+        }
+
+        bits = log2stereo(s->sampleptrs[i][0], s->sampleptrs[i][1],
+                          s->block_samples, info->log_limit);
+        if (bits >= info->best_bits)
+            break;
+        lower = 1;
+        info->best_bits = bits;
+        CLEAR(s->decorr_passes);
+        memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * i);
+        memcpy(s->sampleptrs[info->nterms + 1][0], s->sampleptrs[i][0],
+               s->block_samples * 4);
+        memcpy(s->sampleptrs[info->nterms + 1][1], s->sampleptrs[i][1],
+               s->block_samples * 4);
+    }
+
+    for (d = delta + 1; !lower && d <= 7; d++) {
+        for (i = 0; i < info->nterms && s->decorr_passes[i].value; i++) {
+            info->dps[i].value = s->decorr_passes[i].value;
+            info->dps[i].delta = d;
+            decorr_stereo_buffer(info,
+                                 s->sampleptrs[i  ][0], s->sampleptrs[i  ][1],
+                                 s->sampleptrs[i+1][0], s->sampleptrs[i+1][1],
+                                 s->block_samples, i);
+        }
+
+        bits = log2stereo(s->sampleptrs[i][0], s->sampleptrs[i][1],
+                          s->block_samples, info->log_limit);
+
+        if (bits < info->best_bits) {
+            info->best_bits = bits;
+            CLEAR(s->decorr_passes);
+            memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * i);
+            memcpy(s->sampleptrs[info->nterms + 1][0],
+                   s->sampleptrs[i][0], s->block_samples * 4);
+            memcpy(s->sampleptrs[info->nterms + 1][1],
+                   s->sampleptrs[i][1], s->block_samples * 4);
+        }
+        else
+            break;
+    }
+}
+
+static void recurse_stereo(WavPackEncodeContext *s, WavPackExtraInfo *info,
+                           int depth, int delta, uint32_t input_bits)
+{
+    int term, branches = s->num_branches - depth;
+    int32_t *in_left, *in_right, *out_left, *out_right;
+    uint32_t term_bits[22], bits;
+
+    if (branches < 1 || depth + 1 == info->nterms)
+        branches = 1;
+
+    CLEAR(term_bits);
+    in_left   = s->sampleptrs[depth    ][0];
+    in_right  = s->sampleptrs[depth    ][1];
+    out_left  = s->sampleptrs[depth + 1][0];
+    out_right = s->sampleptrs[depth + 1][1];
+
+    for (term = -3; term <= 18; term++) {
+        if (!term || (term > 8 && term < 17))
+            continue;
+
+        if (term == 17 && branches == 1 && depth + 1 < info->nterms)
+            continue;
+
+        if (term == -1 || term == -2)
+            if (!(s->flags & WV_CROSS_DECORR))
+                continue;
+
+        if (!s->extra_flags && (term > 4 && term < 17))
+            continue;
+
+        info->dps[depth].value = term;
+        info->dps[depth].delta = delta;
+        decorr_stereo_buffer(info, in_left, in_right, out_left, out_right,
+                             s->block_samples, depth);
+        bits = log2stereo(out_left, out_right, s->block_samples, info->log_limit);
+
+        if (bits < info->best_bits) {
+            info->best_bits = bits;
+            CLEAR(s->decorr_passes);
+            memcpy(s->decorr_passes, info->dps, sizeof(info->dps[0]) * (depth + 1));
+            memcpy(s->sampleptrs[info->nterms + 1][0], s->sampleptrs[depth + 1][0],
+                   s->block_samples * 4);
+            memcpy(s->sampleptrs[info->nterms + 1][1], s->sampleptrs[depth + 1][1],
+                   s->block_samples * 4);
+        }
+
+        term_bits[term + 3] = bits;
+    }
+
+    while (depth + 1 < info->nterms && branches--) {
+        uint32_t local_best_bits = input_bits;
+        int best_term = 0, i;
+
+        for (i = 0; i < 22; i++)
+            if (term_bits[i] && term_bits[i] < local_best_bits) {
+                local_best_bits = term_bits[i];
+                best_term = i - 3;
+            }
+
+        if (!best_term)
+            break;
+
+        term_bits[best_term + 3] = 0;
+
+        info->dps[depth].value = best_term;
+        info->dps[depth].delta = delta;
+        decorr_stereo_buffer(info, in_left, in_right, out_left, out_right,
+                             s->block_samples, depth);
+
+        recurse_stereo(s, info, depth + 1, delta, local_best_bits);
+    }
+}
+
+static void analyze_stereo(WavPackEncodeContext *s,
+                           int32_t *in_left, int32_t *in_right,
+                           int do_samples)
+{
+    WavPackExtraInfo info;
+    int i;
+
+    info.gt16bit = ((s->flags & MAG_MASK) >> MAG_LSB) >= 16;
+
+    info.log_limit = (((s->flags & MAG_MASK) >> MAG_LSB) + 4) * 256;
+    info.log_limit = FFMIN(6912, info.log_limit);
+
+    info.nterms = s->num_terms;
+
+    if (allocate_buffers2(s, s->num_terms))
+        return;
+
+    memcpy(info.dps, s->decorr_passes, sizeof(info.dps));
+    memcpy(s->sampleptrs[0][0], in_left,  s->block_samples * 4);
+    memcpy(s->sampleptrs[0][1], in_right, s->block_samples * 4);
+
+    for (i = 0; i < info.nterms && info.dps[i].value; i++)
+        if (info.gt16bit)
+            decorr_stereo(s->sampleptrs[i    ][0], s->sampleptrs[i    ][1],
+                          s->sampleptrs[i + 1][0], s->sampleptrs[i + 1][1],
+                          s->block_samples, info.dps + i, 1);
+        else
+            decorr_stereo_quick(s->sampleptrs[i    ][0], s->sampleptrs[i    ][1],
+                                s->sampleptrs[i + 1][0], s->sampleptrs[i + 1][1],
+                                s->block_samples, info.dps + i);
+
+    info.best_bits = log2stereo(s->sampleptrs[info.nterms][0], s->sampleptrs[info.nterms][1],
+                                s->block_samples, 0);
+
+    memcpy(s->sampleptrs[info.nterms + 1][0], s->sampleptrs[i][0], s->block_samples * 4);
+    memcpy(s->sampleptrs[info.nterms + 1][1], s->sampleptrs[i][1], s->block_samples * 4);
+
+    if (s->extra_flags & EXTRA_BRANCHES)
+        recurse_stereo(s, &info, 0, (int) floor(s->delta_decay + 0.5),
+                       log2stereo(s->sampleptrs[0][0], s->sampleptrs[0][1],
+                                  s->block_samples, 0));
+
+    if (s->extra_flags & EXTRA_SORT_FIRST)
+        sort_stereo(s, &info);
+
+    if (s->extra_flags & EXTRA_TRY_DELTAS) {
+        delta_stereo(s, &info);
+
+        if ((s->extra_flags & EXTRA_ADJUST_DELTAS) && s->decorr_passes[0].value)
+            s->delta_decay = (float)((s->delta_decay * 2.0 + s->decorr_passes[0].delta) / 3.0);
+        else
+            s->delta_decay = 2.0;
+    }
+
+    if (s->extra_flags & EXTRA_SORT_LAST)
+        sort_stereo(s, &info);
+
+    if (do_samples) {
+        memcpy(in_left,  s->sampleptrs[info.nterms + 1][0], s->block_samples * 4);
+        memcpy(in_right, s->sampleptrs[info.nterms + 1][1], s->block_samples * 4);
+    }
+
+    for (i = 0; i < info.nterms; i++)
+        if (!s->decorr_passes[i].value)
+            break;
+
+    s->num_terms = i;
+}
+
+static int wv_stereo(WavPackEncodeContext *s,
+                     int32_t *samples_l, int32_t *samples_r,
+                     int no_history, int do_samples)
+{
+    struct Decorr temp_decorr_pass, save_decorr_passes[MAX_TERMS] = {{0}};
+    int nb_samples = s->block_samples, ret;
+    int buf_size = sizeof(int32_t) * nb_samples;
+    int log_limit, force_js = 0, force_ts = 0, got_js = 0, pi, i;
+    uint32_t best_size = UINT32_MAX, size;
+
+    for (i = 0; i < nb_samples; i++)
+        if (samples_l[i] || samples_r[i])
+            break;
+
+    if (i == nb_samples) {
+        s->flags &= ~((uint32_t) WV_JOINT_STEREO);
+        CLEAR(s->decorr_passes);
+        CLEAR(s->w);
+        s->num_terms = 0;
+        return 0;
+    }
+
+    log_limit = (((s->flags & MAG_MASK) >> MAG_LSB) + 4) * 256;
+    log_limit = FFMIN(6912, log_limit);
+
+    if (s->joint) {
+        force_js = s->joint > 0;
+        force_ts = s->joint < 0;
+    }
+
+    if ((ret = allocate_buffers(s)) < 0)
+        return ret;
+
+    if (no_history || s->num_passes >= 7)
+        s->best_decorr = s->mask_decorr = 0;
+
+    for (pi = 0; pi < s->num_passes;) {
+        const WavPackDecorrSpec *wpds;
+        int nterms, c, j;
+
+        if (!pi)
+            c = s->best_decorr;
+        else {
+            if (s->mask_decorr == 0)
+                c = 0;
+            else
+                c = (s->best_decorr & (s->mask_decorr - 1)) | s->mask_decorr;
+
+            if (c == s->best_decorr) {
+                s->mask_decorr = s->mask_decorr ? ((s->mask_decorr << 1) & (s->num_decorrs - 1)) : 1;
+                continue;
+            }
+        }
+
+        wpds = &s->decorr_specs[c];
+        nterms = decorr_filter_nterms[s->decorr_filter];
+
+        while (1) {
+            if (force_js || (wpds->joint_stereo && !force_ts)) {
+                if (!got_js) {
+                    av_fast_padded_malloc(&s->js_left,  &s->js_left_size,  buf_size);
+                    av_fast_padded_malloc(&s->js_right, &s->js_right_size, buf_size);
+                    memcpy(s->js_left,  samples_l, buf_size);
+                    memcpy(s->js_right, samples_r, buf_size);
+
+                    for (i = 0; i < nb_samples; i++)
+                        s->js_right[i] += ((s->js_left[i] -= s->js_right[i]) >> 1);
+                    got_js = 1;
+                }
+
+                memcpy(s->temp_buffer[0][0], s->js_left,  buf_size);
+                memcpy(s->temp_buffer[0][1], s->js_right, buf_size);
+            } else {
+                memcpy(s->temp_buffer[0][0], samples_l, buf_size);
+                memcpy(s->temp_buffer[0][1], samples_r, buf_size);
+            }
+
+            CLEAR(save_decorr_passes);
+
+            for (j = 0; j < nterms; j++) {
+                CLEAR(temp_decorr_pass);
+                temp_decorr_pass.delta = wpds->delta;
+                temp_decorr_pass.value = wpds->terms[j];
+
+                if (temp_decorr_pass.value < 0 && !(s->flags & WV_CROSS_DECORR))
+                    temp_decorr_pass.value = -3;
+
+                decorr_stereo(s->temp_buffer[ j&1][0], s->temp_buffer[ j&1][1],
+                              s->temp_buffer[~j&1][0], s->temp_buffer[~j&1][1],
+                              FFMIN(2048, nb_samples), &temp_decorr_pass, -1);
+
+                if (j) {
+                    CLEAR(temp_decorr_pass.samplesA);
+                    CLEAR(temp_decorr_pass.samplesB);
+                } else {
+                    reverse_decorr(&temp_decorr_pass);
+                }
+
+                memcpy(save_decorr_passes + j, &temp_decorr_pass, sizeof(struct Decorr));
+
+                if (((s->flags & MAG_MASK) >> MAG_LSB) >= 16)
+                    decorr_stereo(s->temp_buffer[ j&1][0], s->temp_buffer[ j&1][1],
+                                  s->temp_buffer[~j&1][0], s->temp_buffer[~j&1][1],
+                                  nb_samples, &temp_decorr_pass, 1);
+                else
+                    decorr_stereo_quick(s->temp_buffer[ j&1][0], s->temp_buffer[ j&1][1],
+                                        s->temp_buffer[~j&1][0], s->temp_buffer[~j&1][1],
+                                        nb_samples, &temp_decorr_pass);
+            }
+
+            size = log2stereo(s->temp_buffer[j&1][0], s->temp_buffer[j&1][1],
+                              nb_samples, log_limit);
+            if (size != UINT32_MAX || !nterms)
+                break;
+            nterms >>= 1;
+        }
+
+        if (size < best_size) {
+            memcpy(s->best_buffer[0], s->temp_buffer[j&1][0], buf_size);
+            memcpy(s->best_buffer[1], s->temp_buffer[j&1][1], buf_size);
+            memcpy(s->decorr_passes, save_decorr_passes, sizeof(struct Decorr) * MAX_TERMS);
+            s->num_terms = nterms;
+            s->best_decorr = c;
+            best_size = size;
+        }
+
+        if (pi++)
+            s->mask_decorr = s->mask_decorr ? ((s->mask_decorr << 1) & (s->num_decorrs - 1)) : 1;
+    }
+
+    if (force_js || (s->decorr_specs[s->best_decorr].joint_stereo && !force_ts))
+        s->flags |= WV_JOINT_STEREO;
+    else
+        s->flags &= ~((uint32_t) WV_JOINT_STEREO);
+
+    if (s->extra_flags) {
+        if (s->flags & WV_JOINT_STEREO) {
+            analyze_stereo(s, s->js_left, s->js_right, do_samples);
+
+            if (do_samples) {
+                memcpy(samples_l, s->js_left,  buf_size);
+                memcpy(samples_r, s->js_right, buf_size);
+            }
+        } else
+            analyze_stereo(s, samples_l, samples_r, do_samples);
+    } else if (do_samples) {
+        memcpy(samples_l, s->best_buffer[0], buf_size);
+        memcpy(samples_r, s->best_buffer[1], buf_size);
+    }
+
+    if (s->extra_flags || no_history ||
+        s->joint_stereo != s->decorr_specs[s->best_decorr].joint_stereo) {
+        s->joint_stereo = s->decorr_specs[s->best_decorr].joint_stereo;
+        CLEAR(s->w);
+        scan_word(s, &s->w.c[0], s->best_buffer[0], nb_samples, -1);
+        scan_word(s, &s->w.c[1], s->best_buffer[1], nb_samples, -1);
+    }
+    return 0;
+}
+
+#define count_bits(av) ( \
+ (av) < (1 << 8) ? nbits_table[av] : \
+  ( \
+   (av) < (1L << 16) ? nbits_table[(av) >> 8] + 8 : \
+   ((av) < (1L << 24) ? nbits_table[(av) >> 16] + 16 : nbits_table[(av) >> 24] + 24) \
+  ) \
+)
+
+static void encode_flush(WavPackEncodeContext *s)
+{
+    WavPackWords *w = &s->w;
+    PutBitContext *pb = &s->pb;
+
+    if (w->zeros_acc) {
+        int cbits = count_bits(w->zeros_acc);
+
+        do {
+            if (cbits > 31) {
+                put_bits(pb, 31, 0x7FFFFFFF);
+                cbits -= 31;
+            } else {
+                put_bits(pb, cbits, (1 << cbits) - 1);
+                cbits = 0;
+            }
+        } while (cbits);
+
+        put_bits(pb, 1, 0);
+
+        while (w->zeros_acc > 1) {
+            put_bits(pb, 1, w->zeros_acc & 1);
+            w->zeros_acc >>= 1;
+        }
+
+        w->zeros_acc = 0;
+    }
+
+    if (w->holding_one) {
+        if (w->holding_one >= 16) {
+            int cbits;
+
+            put_bits(pb, 16, (1 << 16) - 1);
+            put_bits(pb, 1, 0);
+            w->holding_one -= 16;
+            cbits = count_bits(w->holding_one);
+
+            do {
+                if (cbits > 31) {
+                    put_bits(pb, 31, 0x7FFFFFFF);
+                    cbits -= 31;
+                } else {
+                    put_bits(pb, cbits, (1 << cbits) - 1);
+                    cbits = 0;
+                }
+            } while (cbits);
+
+            put_bits(pb, 1, 0);
+
+            while (w->holding_one > 1) {
+                put_bits(pb, 1, w->holding_one & 1);
+                w->holding_one >>= 1;
+            }
+
+            w->holding_zero = 0;
+        } else {
+            put_bits(pb, w->holding_one, (1 << w->holding_one) - 1);
+        }
+
+        w->holding_one = 0;
+    }
+
+    if (w->holding_zero) {
+        put_bits(pb, 1, 0);
+        w->holding_zero = 0;
+    }
+
+    if (w->pend_count) {
+        put_bits(pb, w->pend_count, w->pend_data);
+        w->pend_data = w->pend_count = 0;
+    }
+}
+
+static void wavpack_encode_sample(WavPackEncodeContext *s, WvChannel *c, int32_t sample)
+{
+    WavPackWords *w = &s->w;
+    uint32_t ones_count, low, high;
+    int sign = ((sample) < 0) ? 1 : 0;
+
+    if (s->w.c[0].median[0] < 2 && !s->w.holding_zero && s->w.c[1].median[0] < 2) {
+        if (w->zeros_acc) {
+            if (sample)
+                encode_flush(s);
+            else {
+                w->zeros_acc++;
+                return;
+            }
+        } else if (sample) {
+            put_bits(&s->pb, 1, 0);
+        } else {
+            CLEAR(s->w.c[0].median);
+            CLEAR(s->w.c[1].median);
+            w->zeros_acc = 1;
+            return;
+        }
+    }
+
+    if (sign)
+        sample = ~sample;
+
+    if (sample < (int32_t) GET_MED(0)) {
+        ones_count = low = 0;
+        high = GET_MED(0) - 1;
+        DEC_MED(0);
+    } else {
+        low = GET_MED(0);
+        INC_MED(0);
+
+        if (sample - low < GET_MED(1)) {
+            ones_count = 1;
+            high = low + GET_MED(1) - 1;
+            DEC_MED(1);
+        } else {
+            low += GET_MED(1);
+            INC_MED(1);
+
+            if (sample - low < GET_MED(2)) {
+                ones_count = 2;
+                high = low + GET_MED(2) - 1;
+                DEC_MED(2);
+            } else {
+                ones_count = 2 + (sample - low) / GET_MED(2);
+                low += (ones_count - 2) * GET_MED(2);
+                high = low + GET_MED(2) - 1;
+                INC_MED(2);
+            }
+        }
+    }
+
+    if (w->holding_zero) {
+        if (ones_count)
+            w->holding_one++;
+
+        encode_flush(s);
+
+        if (ones_count) {
+            w->holding_zero = 1;
+            ones_count--;
+        } else
+            w->holding_zero = 0;
+    } else
+        w->holding_zero = 1;
+
+    w->holding_one = ones_count * 2;
+
+    if (high != low) {
+        uint32_t maxcode = high - low, code = sample - low;
+        int bitcount = count_bits(maxcode);
+        uint32_t extras = (1 << bitcount) - maxcode - 1;
+
+        if (code < extras) {
+            w->pend_data |= code << w->pend_count;
+            w->pend_count += bitcount - 1;
+        } else {
+            w->pend_data |= ((code + extras) >> 1) << w->pend_count;
+            w->pend_count += bitcount - 1;
+            w->pend_data |= ((code + extras) & 1) << w->pend_count++;
+        }
+    }
+
+    w->pend_data |= ((int32_t) sign << w->pend_count++);
+
+    if (!w->holding_zero)
+        encode_flush(s);
+}
+
+static void pack_int32(WavPackEncodeContext *s,
+                       int32_t *samples_l, int32_t *samples_r,
+                       int nb_samples)
+{
+    const int sent_bits = s->int32_sent_bits;
+    int32_t value, mask = (1 << sent_bits) - 1;
+    PutBitContext *pb = &s->pb;
+    int i, pre_shift;
+
+    pre_shift = s->int32_zeros + s->int32_ones + s->int32_dups;
+
+    if (!sent_bits)
+        return;
+
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++) {
+            value = (samples_l[i] >> pre_shift) & mask;
+            put_bits(pb, sent_bits, value);
+        }
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            value = (samples_l[i] >> pre_shift) & mask;
+            put_bits(pb, sent_bits, value);
+            value = (samples_r[i] >> pre_shift) & mask;
+            put_bits(pb, sent_bits, value);
+        }
+    }
+}
+
+static void pack_float_sample(WavPackEncodeContext *s, int32_t *sample)
+{
+    const int max_exp = s->float_max_exp;
+    PutBitContext *pb = &s->pb;
+    int32_t value, shift_count;
+
+    if (get_exponent(*sample) == 255) {
+        if (get_mantissa(*sample)) {
+            put_bits(pb, 1, 1);
+            put_bits(pb, 23, get_mantissa(*sample));
+        } else {
+            put_bits(pb, 1, 0);
+        }
+
+        value = 0x1000000;
+        shift_count = 0;
+    } else if (get_exponent(*sample)) {
+        shift_count = max_exp - get_exponent(*sample);
+        value = 0x800000 + get_mantissa(*sample);
+    } else {
+        shift_count = max_exp ? max_exp - 1 : 0;
+        value = get_mantissa(*sample);
+    }
+
+    if (shift_count < 25)
+        value >>= shift_count;
+    else
+        value = 0;
+
+    if (!value) {
+        if (s->float_flags & FLOAT_ZEROS_SENT) {
+            if (get_exponent(*sample) || get_mantissa(*sample)) {
+                put_bits(pb, 1, 1);
+                put_bits(pb, 23, get_mantissa(*sample));
+
+                if (max_exp >= 25)
+                    put_bits(pb, 8, get_exponent(*sample));
+
+                put_bits(pb, 1, get_sign(*sample));
+            } else {
+                put_bits(pb, 1, 0);
+
+                if (s->float_flags & FLOAT_NEG_ZEROS)
+                    put_bits(pb, 1, get_sign(*sample));
+            }
+        }
+    } else if (shift_count) {
+        if (s->float_flags & FLOAT_SHIFT_SENT) {
+            int32_t data = get_mantissa(*sample) & ((1 << shift_count) - 1);
+            put_bits(pb, shift_count, data);
+        } else if (s->float_flags & FLOAT_SHIFT_SAME) {
+            put_bits(pb, 1, get_mantissa(*sample) & 1);
+        }
+    }
+}
+
+static void pack_float(WavPackEncodeContext *s,
+                       int32_t *samples_l, int32_t *samples_r,
+                       int nb_samples)
+{
+    int i;
+
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++)
+            pack_float_sample(s, &samples_l[i]);
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            pack_float_sample(s, &samples_l[i]);
+            pack_float_sample(s, &samples_r[i]);
+        }
+    }
+}
+
+static void decorr_stereo_pass2(struct Decorr *dpp,
+                                int32_t *samples_l, int32_t *samples_r,
+                                int nb_samples)
+{
+    int i, m, k;
+
+    switch (dpp->value) {
+    case 17:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+            dpp->samplesA[1] = dpp->samplesA[0];
+            samples_l[i] = tmp = (dpp->samplesA[0] = samples_l[i]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = 2 * dpp->samplesB[0] - dpp->samplesB[1];
+            dpp->samplesB[1] = dpp->samplesB[0];
+            samples_r[i] = tmp = (dpp->samplesB[0] = samples_r[i]) - APPLY_WEIGHT(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    case 18:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[0] + ((dpp->samplesA[0] - dpp->samplesA[1]) >> 1);
+            dpp->samplesA[1] = dpp->samplesA[0];
+            samples_l[i] = tmp = (dpp->samplesA[0] = samples_l[i]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[0] + ((dpp->samplesB[0] - dpp->samplesB[1]) >> 1);
+            dpp->samplesB[1] = dpp->samplesB[0];
+            samples_r[i] = tmp = (dpp->samplesB[0] = samples_r[i]) - APPLY_WEIGHT(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    default:
+        for (m = 0, k = dpp->value & (MAX_TERM - 1), i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[m];
+            samples_l[i] = tmp = (dpp->samplesA[k] = samples_l[i]) - APPLY_WEIGHT(dpp->weightA, sam);
+            UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[m];
+            samples_r[i] = tmp = (dpp->samplesB[k] = samples_r[i]) - APPLY_WEIGHT(dpp->weightB, sam);
+            UPDATE_WEIGHT(dpp->weightB, dpp->delta, sam, tmp);
+
+            m = (m + 1) & (MAX_TERM - 1);
+            k = (k + 1) & (MAX_TERM - 1);
+        }
+        if (m) {
+            int32_t temp_A[MAX_TERM], temp_B[MAX_TERM];
+
+            memcpy(temp_A, dpp->samplesA, sizeof (dpp->samplesA));
+            memcpy(temp_B, dpp->samplesB, sizeof (dpp->samplesB));
+
+            for (k = 0; k < MAX_TERM; k++) {
+                dpp->samplesA[k] = temp_A[m];
+                dpp->samplesB[k] = temp_B[m];
+                m = (m + 1) & (MAX_TERM - 1);
+            }
+        }
+        break;
+    case -1:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            samples_l[i] = tmp = (sam_B = samples_l[i]) - APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+
+            samples_r[i] = tmp = (dpp->samplesA[0] = samples_r[i]) - APPLY_WEIGHT(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+        }
+        break;
+    case -2:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_B = dpp->samplesB[0];
+            samples_r[i] = tmp = (sam_A = samples_r[i]) - APPLY_WEIGHT(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+
+            samples_l[i] = tmp = (dpp->samplesB[0] = samples_l[i]) - APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+        }
+        break;
+    case -3:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            sam_B = dpp->samplesB[0];
+
+            dpp->samplesA[0] = tmp = samples_r[i];
+            samples_r[i] = tmp -= APPLY_WEIGHT(dpp->weightB, sam_B);
+            UPDATE_WEIGHT_CLIP(dpp->weightB, dpp->delta, sam_B, tmp);
+
+            dpp->samplesB[0] = tmp = samples_l[i];
+            samples_l[i] = tmp -= APPLY_WEIGHT(dpp->weightA, sam_A);
+            UPDATE_WEIGHT_CLIP(dpp->weightA, dpp->delta, sam_A, tmp);
+        }
+        break;
+    }
+}
+
+#define update_weight_d2(weight, delta, source, result) \
+    if (source && result) \
+        weight -= (((source ^ result) >> 29) & 4) - 2;
+
+#define update_weight_clip_d2(weight, delta, source, result) \
+    if (source && result) { \
+        const int32_t s = (source ^ result) >> 31; \
+        if ((weight = (weight ^ s) + (2 - s)) > 1024) weight = 1024; \
+        weight = (weight ^ s) - s; \
+    }
+
+static void decorr_stereo_pass_id2(struct Decorr *dpp,
+                                   int32_t *samples_l, int32_t *samples_r,
+                                   int nb_samples)
+{
+    int i, m, k;
+
+    switch (dpp->value) {
+    case 17:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+            dpp->samplesA[1] = dpp->samplesA[0];
+            samples_l[i] = tmp = (dpp->samplesA[0] = samples_l[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            update_weight_d2(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = 2 * dpp->samplesB[0] - dpp->samplesB[1];
+            dpp->samplesB[1] = dpp->samplesB[0];
+            samples_r[i] = tmp = (dpp->samplesB[0] = samples_r[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            update_weight_d2(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    case 18:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[0] + ((dpp->samplesA[0] - dpp->samplesA[1]) >> 1);
+            dpp->samplesA[1] = dpp->samplesA[0];
+            samples_l[i] = tmp = (dpp->samplesA[0] = samples_l[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            update_weight_d2(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[0] + ((dpp->samplesB[0] - dpp->samplesB[1]) >> 1);
+            dpp->samplesB[1] = dpp->samplesB[0];
+            samples_r[i] = tmp = (dpp->samplesB[0] = samples_r[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            update_weight_d2(dpp->weightB, dpp->delta, sam, tmp);
+        }
+        break;
+    default:
+        for (m = 0, k = dpp->value & (MAX_TERM - 1), i = 0; i < nb_samples; i++) {
+            int32_t sam, tmp;
+
+            sam = dpp->samplesA[m];
+            samples_l[i] = tmp = (dpp->samplesA[k] = samples_l[i]) - APPLY_WEIGHT_I(dpp->weightA, sam);
+            update_weight_d2(dpp->weightA, dpp->delta, sam, tmp);
+
+            sam = dpp->samplesB[m];
+            samples_r[i] = tmp = (dpp->samplesB[k] = samples_r[i]) - APPLY_WEIGHT_I(dpp->weightB, sam);
+            update_weight_d2(dpp->weightB, dpp->delta, sam, tmp);
+
+            m = (m + 1) & (MAX_TERM - 1);
+            k = (k + 1) & (MAX_TERM - 1);
+        }
+
+        if (m) {
+            int32_t temp_A[MAX_TERM], temp_B[MAX_TERM];
+
+            memcpy(temp_A, dpp->samplesA, sizeof(dpp->samplesA));
+            memcpy(temp_B, dpp->samplesB, sizeof(dpp->samplesB));
+
+            for (k = 0; k < MAX_TERM; k++) {
+                dpp->samplesA[k] = temp_A[m];
+                dpp->samplesB[k] = temp_B[m];
+                m = (m + 1) & (MAX_TERM - 1);
+            }
+        }
+        break;
+    case -1:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            samples_l[i] = tmp = (sam_B = samples_l[i]) - APPLY_WEIGHT_I(dpp->weightA, sam_A);
+            update_weight_clip_d2(dpp->weightA, dpp->delta, sam_A, tmp);
+
+            samples_r[i] = tmp = (dpp->samplesA[0] = samples_r[i]) - APPLY_WEIGHT_I(dpp->weightB, sam_B);
+            update_weight_clip_d2(dpp->weightB, dpp->delta, sam_B, tmp);
+        }
+        break;
+    case -2:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_B = dpp->samplesB[0];
+            samples_r[i] = tmp = (sam_A = samples_r[i]) - APPLY_WEIGHT_I(dpp->weightB, sam_B);
+            update_weight_clip_d2(dpp->weightB, dpp->delta, sam_B, tmp);
+
+            samples_l[i] = tmp = (dpp->samplesB[0] = samples_l[i]) - APPLY_WEIGHT_I(dpp->weightA, sam_A);
+            update_weight_clip_d2(dpp->weightA, dpp->delta, sam_A, tmp);
+        }
+        break;
+    case -3:
+        for (i = 0; i < nb_samples; i++) {
+            int32_t sam_A, sam_B, tmp;
+
+            sam_A = dpp->samplesA[0];
+            sam_B = dpp->samplesB[0];
+
+            dpp->samplesA[0] = tmp = samples_r[i];
+            samples_r[i] = tmp -= APPLY_WEIGHT_I(dpp->weightB, sam_B);
+            update_weight_clip_d2(dpp->weightB, dpp->delta, sam_B, tmp);
+
+            dpp->samplesB[0] = tmp = samples_l[i];
+            samples_l[i] = tmp -= APPLY_WEIGHT_I(dpp->weightA, sam_A);
+            update_weight_clip_d2(dpp->weightA, dpp->delta, sam_A, tmp);
+        }
+        break;
+    }
+}
+
+static void put_metadata_block(PutByteContext *pb, int flags, int size)
+{
+    if (size & 1)
+        flags |= WP_IDF_ODD;
+
+    bytestream2_put_byte(pb, flags);
+    bytestream2_put_byte(pb, (size + 1) >> 1);
+}
+
+static int wavpack_encode_block(WavPackEncodeContext *s,
+                                int32_t *samples_l, int32_t *samples_r,
+                                uint8_t *out, int out_size)
+{
+    int block_size, start, end, data_size, tcount, temp, m = 0;
+    int i, j, ret, got_extra = 0, nb_samples = s->block_samples;
+    uint32_t crc = 0xffffffffu;
+    struct Decorr *dpp;
+    PutByteContext pb;
+
+    if (!(s->flags & WV_MONO) && s->optimize_mono) {
+        int32_t lor = 0, diff = 0;
+
+        for (i = 0; i < nb_samples; i++) {
+            lor  |= samples_l[i] | samples_r[i];
+            diff |= samples_l[i] - samples_r[i];
+
+            if (lor && diff)
+                break;
+        }
+
+        if (i == nb_samples && lor && !diff) {
+            s->flags &= ~(WV_JOINT_STEREO | WV_CROSS_DECORR);
+            s->flags |= WV_FALSE_STEREO;
+
+            if (!s->false_stereo) {
+                s->false_stereo = 1;
+                s->num_terms = 0;
+                CLEAR(s->w);
+            }
+        } else if (s->false_stereo) {
+            s->false_stereo = 0;
+            s->num_terms = 0;
+            CLEAR(s->w);
+        }
+    }
+
+    if (s->flags & SHIFT_MASK) {
+        int shift = (s->flags & SHIFT_MASK) >> SHIFT_LSB;
+        int mag = (s->flags & MAG_MASK) >> MAG_LSB;
+
+        if (s->flags & WV_MONO_DATA)
+            shift_mono(samples_l, nb_samples, shift);
+        else
+            shift_stereo(samples_l, samples_r, nb_samples, shift);
+
+        if ((mag -= shift) < 0)
+            s->flags &= ~MAG_MASK;
+        else
+            s->flags -= (1 << MAG_LSB) * shift;
+    }
+
+    if ((s->flags & WV_FLOAT_DATA) || (s->flags & MAG_MASK) >> MAG_LSB >= 24) {
+        av_fast_padded_malloc(&s->orig_l, &s->orig_l_size, sizeof(int32_t) * nb_samples);
+        av_fast_padded_malloc(&s->orig_r, &s->orig_r_size, sizeof(int32_t) * nb_samples);
+        memcpy(s->orig_l, samples_l, sizeof(int32_t) * nb_samples);
+        memcpy(s->orig_r, samples_r, sizeof(int32_t) * nb_samples);
+
+        if (s->flags & WV_FLOAT_DATA)
+            got_extra = scan_float(s, samples_l, samples_r, nb_samples);
+        else
+            got_extra = scan_int32(s, samples_l, samples_r, nb_samples);
+        s->num_terms = 0;
+    } else {
+        scan_int23(s, samples_l, samples_r, nb_samples);
+        if (s->shift != s->int32_zeros + s->int32_ones + s->int32_dups) {
+            s->shift = s->int32_zeros + s->int32_ones + s->int32_dups;
+            s->num_terms = 0;
+        }
+    }
+
+    if (!s->num_passes && !s->num_terms) {
+        s->num_passes = 1;
+
+        if (s->flags & WV_MONO_DATA)
+            ret = wv_mono(s, samples_l, 1, 0);
+        else
+            ret = wv_stereo(s, samples_l, samples_r, 1, 0);
+
+        s->num_passes = 0;
+    }
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++)
+            crc += (crc << 1) + samples_l[i];
+
+        if (s->num_passes)
+            ret = wv_mono(s, samples_l, !s->num_terms, 1);
+    } else {
+        for (i = 0; i < nb_samples; i++)
+            crc += (crc << 3) + (samples_l[i] << 1) + samples_l[i] + samples_r[i];
+
+        if (s->num_passes)
+            ret = wv_stereo(s, samples_l, samples_r, !s->num_terms, 1);
+    }
+    if (ret < 0)
+        return ret;
+
+    if (!s->ch_offset)
+        s->flags |= WV_INITIAL_BLOCK;
+
+    s->ch_offset += 1 + !(s->flags & WV_MONO);
+
+    if (s->ch_offset == s->avctx->channels)
+        s->flags |= WV_FINAL_BLOCK;
+
+    bytestream2_init_writer(&pb, out, out_size);
+    bytestream2_put_le32(&pb, MKTAG('w', 'v', 'p', 'k'));
+    bytestream2_put_le32(&pb, 0);
+    bytestream2_put_le16(&pb, 0x410);
+    bytestream2_put_le16(&pb, 0);
+    bytestream2_put_le32(&pb, 0);
+    bytestream2_put_le32(&pb, s->sample_index);
+    bytestream2_put_le32(&pb, nb_samples);
+    bytestream2_put_le32(&pb, s->flags);
+    bytestream2_put_le32(&pb, crc);
+
+    if (s->flags & WV_INITIAL_BLOCK &&
+        s->avctx->channel_layout != AV_CH_LAYOUT_MONO &&
+        s->avctx->channel_layout != AV_CH_LAYOUT_STEREO) {
+        put_metadata_block(&pb, WP_ID_CHANINFO, 5);
+        bytestream2_put_byte(&pb, s->avctx->channels);
+        bytestream2_put_le32(&pb, s->avctx->channel_layout);
+        bytestream2_put_byte(&pb, 0);
+    }
+
+    if ((s->flags & SRATE_MASK) == SRATE_MASK) {
+        put_metadata_block(&pb, WP_ID_SAMPLE_RATE, 3);
+        bytestream2_put_le24(&pb, s->avctx->sample_rate);
+        bytestream2_put_byte(&pb, 0);
+    }
+
+    put_metadata_block(&pb, WP_ID_DECTERMS, s->num_terms);
+    for (i = 0; i < s->num_terms; i++) {
+        struct Decorr *dpp = &s->decorr_passes[i];
+        bytestream2_put_byte(&pb, ((dpp->value + 5) & 0x1f) | ((dpp->delta << 5) & 0xe0));
+    }
+    if (s->num_terms & 1)
+        bytestream2_put_byte(&pb, 0);
+
+#define WRITE_DECWEIGHT(type) do {            \
+        temp = store_weight(type);    \
+        bytestream2_put_byte(&pb, temp);      \
+        type = restore_weight(temp);  \
+    } while (0)
+
+    bytestream2_put_byte(&pb, WP_ID_DECWEIGHTS);
+    bytestream2_put_byte(&pb, 0);
+    start = bytestream2_tell_p(&pb);
+    for (i = s->num_terms - 1; i >= 0; --i) {
+        struct Decorr *dpp = &s->decorr_passes[i];
+
+        if (store_weight(dpp->weightA) ||
+            (!(s->flags & WV_MONO_DATA) && store_weight(dpp->weightB)))
+                break;
+    }
+    tcount = i + 1;
+    for (i = 0; i < s->num_terms; i++) {
+        struct Decorr *dpp = &s->decorr_passes[i];
+        if (i < tcount) {
+            WRITE_DECWEIGHT(dpp->weightA);
+            if (!(s->flags & WV_MONO_DATA))
+                WRITE_DECWEIGHT(dpp->weightB);
+        } else {
+            dpp->weightA = dpp->weightB = 0;
+        }
+    }
+    end = bytestream2_tell_p(&pb);
+    out[start - 2] = WP_ID_DECWEIGHTS | (((end - start) & 1) ? WP_IDF_ODD: 0);
+    out[start - 1] = (end - start + 1) >> 1;
+    if ((end - start) & 1)
+        bytestream2_put_byte(&pb, 0);
+
+#define WRITE_DECSAMPLE(type) do {        \
+        temp = log2s(type);               \
+        type = wp_exp2(temp);             \
+        bytestream2_put_le16(&pb, temp);  \
+    } while (0)
+
+    bytestream2_put_byte(&pb, WP_ID_DECSAMPLES);
+    bytestream2_put_byte(&pb, 0);
+    start = bytestream2_tell_p(&pb);
+    for (i = 0; i < s->num_terms; i++) {
+        struct Decorr *dpp = &s->decorr_passes[i];
+        if (i == 0) {
+            if (dpp->value > MAX_TERM) {
+                WRITE_DECSAMPLE(dpp->samplesA[0]);
+                WRITE_DECSAMPLE(dpp->samplesA[1]);
+                if (!(s->flags & WV_MONO_DATA)) {
+                    WRITE_DECSAMPLE(dpp->samplesB[0]);
+                    WRITE_DECSAMPLE(dpp->samplesB[1]);
+                }
+            } else if (dpp->value < 0) {
+                WRITE_DECSAMPLE(dpp->samplesA[0]);
+                WRITE_DECSAMPLE(dpp->samplesB[0]);
+            } else {
+                for (j = 0; j < dpp->value; j++) {
+                    WRITE_DECSAMPLE(dpp->samplesA[j]);
+                    if (!(s->flags & WV_MONO_DATA))
+                        WRITE_DECSAMPLE(dpp->samplesB[j]);
+                }
+            }
+        } else {
+            CLEAR(dpp->samplesA);
+            CLEAR(dpp->samplesB);
+        }
+    }
+    end = bytestream2_tell_p(&pb);
+    out[start - 1] = (end - start) >> 1;
+
+#define WRITE_CHAN_ENTROPY(chan) do {               \
+        for (i = 0; i < 3; i++) {                   \
+            temp = wp_log2(s->w.c[chan].median[i]); \
+            bytestream2_put_le16(&pb, temp);        \
+            s->w.c[chan].median[i] = wp_exp2(temp); \
+        }                                           \
+    } while (0)
+
+    put_metadata_block(&pb, WP_ID_ENTROPY, 6 * (1 + (!(s->flags & WV_MONO_DATA))));
+    WRITE_CHAN_ENTROPY(0);
+    if (!(s->flags & WV_MONO_DATA))
+        WRITE_CHAN_ENTROPY(1);
+
+    if (s->flags & WV_FLOAT_DATA) {
+        put_metadata_block(&pb, WP_ID_FLOATINFO, 4);
+        bytestream2_put_byte(&pb, s->float_flags);
+        bytestream2_put_byte(&pb, s->float_shift);
+        bytestream2_put_byte(&pb, s->float_max_exp);
+        bytestream2_put_byte(&pb, 127);
+    }
+
+    if (s->flags & WV_INT32_DATA) {
+        put_metadata_block(&pb, WP_ID_INT32INFO, 4);
+        bytestream2_put_byte(&pb, s->int32_sent_bits);
+        bytestream2_put_byte(&pb, s->int32_zeros);
+        bytestream2_put_byte(&pb, s->int32_ones);
+        bytestream2_put_byte(&pb, s->int32_dups);
+    }
+
+    if (s->flags & WV_MONO_DATA && !s->num_passes) {
+        for (i = 0; i < nb_samples; i++) {
+            int32_t code = samples_l[i];
+
+            for (tcount = s->num_terms, dpp = s->decorr_passes; tcount--; dpp++) {
+                int32_t sam;
+
+                if (dpp->value > MAX_TERM) {
+                    if (dpp->value & 1)
+                        sam = 2 * dpp->samplesA[0] - dpp->samplesA[1];
+                    else
+                        sam = (3 * dpp->samplesA[0] - dpp->samplesA[1]) >> 1;
+
+                    dpp->samplesA[1] = dpp->samplesA[0];
+                    dpp->samplesA[0] = code;
+                } else {
+                    sam = dpp->samplesA[m];
+                    dpp->samplesA[(m + dpp->value) & (MAX_TERM - 1)] = code;
+                }
+
+                code -= APPLY_WEIGHT(dpp->weightA, sam);
+                UPDATE_WEIGHT(dpp->weightA, dpp->delta, sam, code);
+            }
+
+            m = (m + 1) & (MAX_TERM - 1);
+            samples_l[i] = code;
+        }
+        if (m) {
+            for (tcount = s->num_terms, dpp = s->decorr_passes; tcount--; dpp++)
+                if (dpp->value > 0 && dpp->value <= MAX_TERM) {
+                int32_t temp_A[MAX_TERM], temp_B[MAX_TERM];
+                int k;
+
+                memcpy(temp_A, dpp->samplesA, sizeof(dpp->samplesA));
+                memcpy(temp_B, dpp->samplesB, sizeof(dpp->samplesB));
+
+                for (k = 0; k < MAX_TERM; k++) {
+                    dpp->samplesA[k] = temp_A[m];
+                    dpp->samplesB[k] = temp_B[m];
+                    m = (m + 1) & (MAX_TERM - 1);
+                }
+            }
+        }
+    } else if (!s->num_passes) {
+        if (s->flags & WV_JOINT_STEREO) {
+            for (i = 0; i < nb_samples; i++)
+                samples_r[i] += ((samples_l[i] -= samples_r[i]) >> 1);
+        }
+
+        for (i = 0; i < s->num_terms; i++) {
+            struct Decorr *dpp = &s->decorr_passes[i];
+            if (((s->flags & MAG_MASK) >> MAG_LSB) >= 16 || dpp->delta != 2)
+                decorr_stereo_pass2(dpp, samples_l, samples_r, nb_samples);
+            else
+                decorr_stereo_pass_id2(dpp, samples_l, samples_r, nb_samples);
+        }
+    }
+
+    bytestream2_put_byte(&pb, WP_ID_DATA | WP_IDF_LONG);
+    init_put_bits(&s->pb, pb.buffer + 3, bytestream2_get_bytes_left_p(&pb));
+    if (s->flags & WV_MONO_DATA) {
+        for (i = 0; i < nb_samples; i++)
+            wavpack_encode_sample(s, &s->w.c[0], s->samples[0][i]);
+    } else {
+        for (i = 0; i < nb_samples; i++) {
+            wavpack_encode_sample(s, &s->w.c[0], s->samples[0][i]);
+            wavpack_encode_sample(s, &s->w.c[1], s->samples[1][i]);
+        }
+    }
+    encode_flush(s);
+    flush_put_bits(&s->pb);
+    data_size = put_bits_count(&s->pb) >> 3;
+    bytestream2_put_le24(&pb, (data_size + 1) >> 1);
+    bytestream2_skip_p(&pb, data_size);
+    if (data_size & 1)
+        bytestream2_put_byte(&pb, 0);
+
+    if (got_extra) {
+        bytestream2_put_byte(&pb, WP_ID_EXTRABITS | WP_IDF_LONG);
+        init_put_bits(&s->pb, pb.buffer + 7, bytestream2_get_bytes_left_p(&pb));
+        if (s->flags & WV_FLOAT_DATA)
+            pack_float(s, s->orig_l, s->orig_r, nb_samples);
+        else
+            pack_int32(s, s->orig_l, s->orig_r, nb_samples);
+        flush_put_bits(&s->pb);
+        data_size = put_bits_count(&s->pb) >> 3;
+        bytestream2_put_le24(&pb, (data_size + 5) >> 1);
+        bytestream2_put_le32(&pb, s->crc_x);
+        bytestream2_skip_p(&pb, data_size);
+        if (data_size & 1)
+            bytestream2_put_byte(&pb, 0);
+    }
+
+    block_size = bytestream2_tell_p(&pb);
+    AV_WL32(out + 4, block_size - 8);
+
+    return block_size;
+}
+
+static void fill_buffer(WavPackEncodeContext *s,
+                        const int8_t *src, int32_t *dst,
+                        int nb_samples)
+{
+    int i;
+
+#define COPY_SAMPLES(type, offset, shift) do {            \
+        const type *sptr = (const type *)src;             \
+        for (i = 0; i < nb_samples; i++)                  \
+            dst[i] = (sptr[i] - offset) >> shift;         \
+    } while (0)
+
+    switch (s->avctx->sample_fmt) {
+    case AV_SAMPLE_FMT_U8P:
+        COPY_SAMPLES(int8_t, 0x80, 0);
+        break;
+    case AV_SAMPLE_FMT_S16P:
+        COPY_SAMPLES(int16_t, 0, 0);
+        break;
+    case AV_SAMPLE_FMT_S32P:
+        if (s->avctx->bits_per_raw_sample <= 24) {
+            COPY_SAMPLES(int32_t, 0, 8);
+            break;
+        }
+    case AV_SAMPLE_FMT_FLTP:
+        memcpy(dst, src, nb_samples * 4);
+    }
+}
+
+static void set_samplerate(WavPackEncodeContext *s)
+{
+    int i;
+
+    for (i = 0; i < 15; i++) {
+        if (wv_rates[i] == s->avctx->sample_rate)
+            break;
+    }
+
+    s->flags = i << SRATE_LSB;
+}
+
+static int wavpack_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
+                                const AVFrame *frame, int *got_packet_ptr)
+{
+    WavPackEncodeContext *s = avctx->priv_data;
+    int buf_size, ret;
+    uint8_t *buf;
+
+    s->block_samples = frame->nb_samples;
+    av_fast_padded_malloc(&s->samples[0], &s->samples_size[0],
+                          sizeof(int32_t) * s->block_samples);
+    if (!s->samples[0])
+        return AVERROR(ENOMEM);
+    if (avctx->channels > 1) {
+        av_fast_padded_malloc(&s->samples[1], &s->samples_size[1],
+                              sizeof(int32_t) * s->block_samples);
+        if (!s->samples[1])
+            return AVERROR(ENOMEM);
+    }
+
+    if ((ret = ff_alloc_packet2(avctx, avpkt, s->block_samples * avctx->channels * 8)) < 0)
+        return ret;
+    buf = avpkt->data;
+    buf_size = avpkt->size;
+
+    for (s->ch_offset = 0; s->ch_offset < avctx->channels;) {
+        set_samplerate(s);
+
+        switch (s->avctx->sample_fmt) {
+        case AV_SAMPLE_FMT_S16P: s->flags |= 1; break;
+        case AV_SAMPLE_FMT_S32P: s->flags |= 3 - (s->avctx->bits_per_raw_sample <= 24); break;
+        case AV_SAMPLE_FMT_FLTP: s->flags |= 3 | WV_FLOAT_DATA;
+        }
+
+        fill_buffer(s, frame->extended_data[s->ch_offset], s->samples[0], s->block_samples);
+        if (avctx->channels - s->ch_offset == 1) {
+            s->flags |= WV_MONO;
+        } else {
+            s->flags |= WV_CROSS_DECORR;
+            fill_buffer(s, frame->extended_data[s->ch_offset + 1], s->samples[1], s->block_samples);
+        }
+
+        s->flags += (1 << MAG_LSB) * ((s->flags & 3) * 8 + 7);
+
+        if ((ret = wavpack_encode_block(s, s->samples[0], s->samples[1],
+                                        buf, buf_size)) < 0)
+            return ret;
+
+        buf      += ret;
+        buf_size -= ret;
+    }
+    s->sample_index += frame->nb_samples;
+
+    avpkt->pts      = frame->pts;
+    avpkt->size     = buf - avpkt->data;
+    avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
+    *got_packet_ptr = 1;
+    return 0;
+}
+
+static av_cold int wavpack_encode_close(AVCodecContext *avctx)
+{
+    WavPackEncodeContext *s = avctx->priv_data;
+    int i;
+
+    for (i = 0; i < MAX_TERMS + 2; i++) {
+        av_freep(&s->sampleptrs[i][0]);
+        av_freep(&s->sampleptrs[i][1]);
+        s->sampleptrs_size[i][0] = s->sampleptrs_size[i][1] = 0;
+    }
+
+    for (i = 0; i < 2; i++) {
+        av_freep(&s->samples[i]);
+        s->samples_size[i] = 0;
+
+        av_freep(&s->best_buffer[i]);
+        s->best_buffer_size[i] = 0;
+
+        av_freep(&s->temp_buffer[i][0]);
+        av_freep(&s->temp_buffer[i][1]);
+        s->temp_buffer_size[i][0] = s->temp_buffer_size[i][1] = 0;
+    }
+
+    av_freep(&s->js_left);
+    av_freep(&s->js_right);
+    s->js_left_size = s->js_right_size = 0;
+
+    av_freep(&s->orig_l);
+    av_freep(&s->orig_r);
+    s->orig_l_size = s->orig_r_size = 0;
+
+    return 0;
+}
+
+#define OFFSET(x) offsetof(WavPackEncodeContext, x)
+#define FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM
+static const AVOption options[] = {
+    { "joint_stereo",  "", OFFSET(joint), AV_OPT_TYPE_INT, {.i64=0},-1, 1, FLAGS, "joint" },
+    { "on",   "mid/side",   0, AV_OPT_TYPE_CONST, {.i64= 1}, 0, 0, FLAGS, "joint"},
+    { "off",  "left/right", 0, AV_OPT_TYPE_CONST, {.i64=-1}, 0, 0, FLAGS, "joint"},
+    { "auto", NULL, 0, AV_OPT_TYPE_CONST, {.i64= 0}, 0, 0, FLAGS, "joint"},
+    { "optimize_mono",        "", OFFSET(optimize_mono), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, FLAGS, "opt_mono" },
+    { "on",   NULL, 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "opt_mono"},
+    { "off",  NULL, 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "opt_mono"},
+    { NULL },
+};
+
+static const AVClass wavpack_encoder_class = {
+    .class_name = "WavPack encoder",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+AVCodec ff_wavpack_encoder = {
+    .name           = "wavpack",
+    .long_name      = NULL_IF_CONFIG_SMALL("WavPack"),
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_WAVPACK,
+    .priv_data_size = sizeof(WavPackEncodeContext),
+    .priv_class     = &wavpack_encoder_class,
+    .init           = wavpack_encode_init,
+    .encode2        = wavpack_encode_frame,
+    .close          = wavpack_encode_close,
+    .capabilities   = CODEC_CAP_SMALL_LAST_FRAME,
+    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_U8P,
+                                                     AV_SAMPLE_FMT_S16P,
+                                                     AV_SAMPLE_FMT_S32P,
+                                                     AV_SAMPLE_FMT_FLTP,
+                                                     AV_SAMPLE_FMT_NONE },
+};