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authorAndreas Rheinhardt <andreas.rheinhardt@outlook.com>2022-10-07 20:17:06 +0200
committerAndreas Rheinhardt <andreas.rheinhardt@outlook.com>2022-10-09 19:45:06 +0200
commit8320e236c1f11e7a397ddce7e4206c11ac9de9a9 (patch)
treeb5b269e924e95747a744c58a17c3d07d21da4d3b /libavcodec/opusdec_celt.c
parent4486ff924202dcfb3121596ff900873483d5ffd1 (diff)
downloadffmpeg-8320e236c1f11e7a397ddce7e4206c11ac9de9a9.tar.gz
avcodec/opus: Rename opus.c->opus_celt.c, opus_celt.c->opusdec_celt.c
Since commit 4fc2531fff112836026aad2bdaf128c9d15a72e3 opus.c contains only the celt stuff shared between decoder and encoder. meanwhile, opus_celt.c is decoder-only. So the new names reflect the actual content better than the current ones. Reviewed-by: Lynne <dev@lynne.ee> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Diffstat (limited to 'libavcodec/opusdec_celt.c')
-rw-r--r--libavcodec/opusdec_celt.c586
1 files changed, 586 insertions, 0 deletions
diff --git a/libavcodec/opusdec_celt.c b/libavcodec/opusdec_celt.c
new file mode 100644
index 0000000000..c2904cc9e0
--- /dev/null
+++ b/libavcodec/opusdec_celt.c
@@ -0,0 +1,586 @@
+/*
+ * Copyright (c) 2012 Andrew D'Addesio
+ * Copyright (c) 2013-2014 Mozilla Corporation
+ * Copyright (c) 2016 Rostislav Pehlivanov <atomnuker@gmail.com>
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * Opus CELT decoder
+ */
+
+#include <float.h>
+
+#include "opus_celt.h"
+#include "opustab.h"
+#include "opus_pvq.h"
+
+/* Use the 2D z-transform to apply prediction in both the time domain (alpha)
+ * and the frequency domain (beta) */
+static void celt_decode_coarse_energy(CeltFrame *f, OpusRangeCoder *rc)
+{
+ int i, j;
+ float prev[2] = { 0 };
+ float alpha = ff_celt_alpha_coef[f->size];
+ float beta = ff_celt_beta_coef[f->size];
+ const uint8_t *model = ff_celt_coarse_energy_dist[f->size][0];
+
+ /* intra frame */
+ if (opus_rc_tell(rc) + 3 <= f->framebits && ff_opus_rc_dec_log(rc, 3)) {
+ alpha = 0.0f;
+ beta = 1.0f - (4915.0f/32768.0f);
+ model = ff_celt_coarse_energy_dist[f->size][1];
+ }
+
+ for (i = 0; i < CELT_MAX_BANDS; i++) {
+ for (j = 0; j < f->channels; j++) {
+ CeltBlock *block = &f->block[j];
+ float value;
+ int available;
+
+ if (i < f->start_band || i >= f->end_band) {
+ block->energy[i] = 0.0;
+ continue;
+ }
+
+ available = f->framebits - opus_rc_tell(rc);
+ if (available >= 15) {
+ /* decode using a Laplace distribution */
+ int k = FFMIN(i, 20) << 1;
+ value = ff_opus_rc_dec_laplace(rc, model[k] << 7, model[k+1] << 6);
+ } else if (available >= 2) {
+ int x = ff_opus_rc_dec_cdf(rc, ff_celt_model_energy_small);
+ value = (x>>1) ^ -(x&1);
+ } else if (available >= 1) {
+ value = -(float)ff_opus_rc_dec_log(rc, 1);
+ } else value = -1;
+
+ block->energy[i] = FFMAX(-9.0f, block->energy[i]) * alpha + prev[j] + value;
+ prev[j] += beta * value;
+ }
+ }
+}
+
+static void celt_decode_fine_energy(CeltFrame *f, OpusRangeCoder *rc)
+{
+ int i;
+ for (i = f->start_band; i < f->end_band; i++) {
+ int j;
+ if (!f->fine_bits[i])
+ continue;
+
+ for (j = 0; j < f->channels; j++) {
+ CeltBlock *block = &f->block[j];
+ int q2;
+ float offset;
+ q2 = ff_opus_rc_get_raw(rc, f->fine_bits[i]);
+ offset = (q2 + 0.5f) * (1 << (14 - f->fine_bits[i])) / 16384.0f - 0.5f;
+ block->energy[i] += offset;
+ }
+ }
+}
+
+static void celt_decode_final_energy(CeltFrame *f, OpusRangeCoder *rc)
+{
+ int priority, i, j;
+ int bits_left = f->framebits - opus_rc_tell(rc);
+
+ for (priority = 0; priority < 2; priority++) {
+ for (i = f->start_band; i < f->end_band && bits_left >= f->channels; i++) {
+ if (f->fine_priority[i] != priority || f->fine_bits[i] >= CELT_MAX_FINE_BITS)
+ continue;
+
+ for (j = 0; j < f->channels; j++) {
+ int q2;
+ float offset;
+ q2 = ff_opus_rc_get_raw(rc, 1);
+ offset = (q2 - 0.5f) * (1 << (14 - f->fine_bits[i] - 1)) / 16384.0f;
+ f->block[j].energy[i] += offset;
+ bits_left--;
+ }
+ }
+ }
+}
+
+static void celt_decode_tf_changes(CeltFrame *f, OpusRangeCoder *rc)
+{
+ int i, diff = 0, tf_select = 0, tf_changed = 0, tf_select_bit;
+ int consumed, bits = f->transient ? 2 : 4;
+
+ consumed = opus_rc_tell(rc);
+ tf_select_bit = (f->size != 0 && consumed+bits+1 <= f->framebits);
+
+ for (i = f->start_band; i < f->end_band; i++) {
+ if (consumed+bits+tf_select_bit <= f->framebits) {
+ diff ^= ff_opus_rc_dec_log(rc, bits);
+ consumed = opus_rc_tell(rc);
+ tf_changed |= diff;
+ }
+ f->tf_change[i] = diff;
+ bits = f->transient ? 4 : 5;
+ }
+
+ if (tf_select_bit && ff_celt_tf_select[f->size][f->transient][0][tf_changed] !=
+ ff_celt_tf_select[f->size][f->transient][1][tf_changed])
+ tf_select = ff_opus_rc_dec_log(rc, 1);
+
+ for (i = f->start_band; i < f->end_band; i++) {
+ f->tf_change[i] = ff_celt_tf_select[f->size][f->transient][tf_select][f->tf_change[i]];
+ }
+}
+
+static void celt_denormalize(CeltFrame *f, CeltBlock *block, float *data)
+{
+ int i, j;
+
+ for (i = f->start_band; i < f->end_band; i++) {
+ float *dst = data + (ff_celt_freq_bands[i] << f->size);
+ float log_norm = block->energy[i] + ff_celt_mean_energy[i];
+ float norm = exp2f(FFMIN(log_norm, 32.0f));
+
+ for (j = 0; j < ff_celt_freq_range[i] << f->size; j++)
+ dst[j] *= norm;
+ }
+}
+
+static void celt_postfilter_apply_transition(CeltBlock *block, float *data)
+{
+ const int T0 = block->pf_period_old;
+ const int T1 = block->pf_period;
+
+ float g00, g01, g02;
+ float g10, g11, g12;
+
+ float x0, x1, x2, x3, x4;
+
+ int i;
+
+ if (block->pf_gains[0] == 0.0 &&
+ block->pf_gains_old[0] == 0.0)
+ return;
+
+ g00 = block->pf_gains_old[0];
+ g01 = block->pf_gains_old[1];
+ g02 = block->pf_gains_old[2];
+ g10 = block->pf_gains[0];
+ g11 = block->pf_gains[1];
+ g12 = block->pf_gains[2];
+
+ x1 = data[-T1 + 1];
+ x2 = data[-T1];
+ x3 = data[-T1 - 1];
+ x4 = data[-T1 - 2];
+
+ for (i = 0; i < CELT_OVERLAP; i++) {
+ float w = ff_celt_window2[i];
+ x0 = data[i - T1 + 2];
+
+ data[i] += (1.0 - w) * g00 * data[i - T0] +
+ (1.0 - w) * g01 * (data[i - T0 - 1] + data[i - T0 + 1]) +
+ (1.0 - w) * g02 * (data[i - T0 - 2] + data[i - T0 + 2]) +
+ w * g10 * x2 +
+ w * g11 * (x1 + x3) +
+ w * g12 * (x0 + x4);
+ x4 = x3;
+ x3 = x2;
+ x2 = x1;
+ x1 = x0;
+ }
+}
+
+static void celt_postfilter(CeltFrame *f, CeltBlock *block)
+{
+ int len = f->blocksize * f->blocks;
+ const int filter_len = len - 2 * CELT_OVERLAP;
+
+ celt_postfilter_apply_transition(block, block->buf + 1024);
+
+ block->pf_period_old = block->pf_period;
+ memcpy(block->pf_gains_old, block->pf_gains, sizeof(block->pf_gains));
+
+ block->pf_period = block->pf_period_new;
+ memcpy(block->pf_gains, block->pf_gains_new, sizeof(block->pf_gains));
+
+ if (len > CELT_OVERLAP) {
+ celt_postfilter_apply_transition(block, block->buf + 1024 + CELT_OVERLAP);
+
+ if (block->pf_gains[0] > FLT_EPSILON && filter_len > 0)
+ f->opusdsp.postfilter(block->buf + 1024 + 2 * CELT_OVERLAP,
+ block->pf_period, block->pf_gains,
+ filter_len);
+
+ block->pf_period_old = block->pf_period;
+ memcpy(block->pf_gains_old, block->pf_gains, sizeof(block->pf_gains));
+ }
+
+ memmove(block->buf, block->buf + len, (1024 + CELT_OVERLAP / 2) * sizeof(float));
+}
+
+static int parse_postfilter(CeltFrame *f, OpusRangeCoder *rc, int consumed)
+{
+ int i;
+
+ memset(f->block[0].pf_gains_new, 0, sizeof(f->block[0].pf_gains_new));
+ memset(f->block[1].pf_gains_new, 0, sizeof(f->block[1].pf_gains_new));
+
+ if (f->start_band == 0 && consumed + 16 <= f->framebits) {
+ int has_postfilter = ff_opus_rc_dec_log(rc, 1);
+ if (has_postfilter) {
+ float gain;
+ int tapset, octave, period;
+
+ octave = ff_opus_rc_dec_uint(rc, 6);
+ period = (16 << octave) + ff_opus_rc_get_raw(rc, 4 + octave) - 1;
+ gain = 0.09375f * (ff_opus_rc_get_raw(rc, 3) + 1);
+ tapset = (opus_rc_tell(rc) + 2 <= f->framebits) ?
+ ff_opus_rc_dec_cdf(rc, ff_celt_model_tapset) : 0;
+
+ for (i = 0; i < 2; i++) {
+ CeltBlock *block = &f->block[i];
+
+ block->pf_period_new = FFMAX(period, CELT_POSTFILTER_MINPERIOD);
+ block->pf_gains_new[0] = gain * ff_celt_postfilter_taps[tapset][0];
+ block->pf_gains_new[1] = gain * ff_celt_postfilter_taps[tapset][1];
+ block->pf_gains_new[2] = gain * ff_celt_postfilter_taps[tapset][2];
+ }
+ }
+
+ consumed = opus_rc_tell(rc);
+ }
+
+ return consumed;
+}
+
+static void process_anticollapse(CeltFrame *f, CeltBlock *block, float *X)
+{
+ int i, j, k;
+
+ for (i = f->start_band; i < f->end_band; i++) {
+ int renormalize = 0;
+ float *xptr;
+ float prev[2];
+ float Ediff, r;
+ float thresh, sqrt_1;
+ int depth;
+
+ /* depth in 1/8 bits */
+ depth = (1 + f->pulses[i]) / (ff_celt_freq_range[i] << f->size);
+ thresh = exp2f(-1.0 - 0.125f * depth);
+ sqrt_1 = 1.0f / sqrtf(ff_celt_freq_range[i] << f->size);
+
+ xptr = X + (ff_celt_freq_bands[i] << f->size);
+
+ prev[0] = block->prev_energy[0][i];
+ prev[1] = block->prev_energy[1][i];
+ if (f->channels == 1) {
+ CeltBlock *block1 = &f->block[1];
+
+ prev[0] = FFMAX(prev[0], block1->prev_energy[0][i]);
+ prev[1] = FFMAX(prev[1], block1->prev_energy[1][i]);
+ }
+ Ediff = block->energy[i] - FFMIN(prev[0], prev[1]);
+ Ediff = FFMAX(0, Ediff);
+
+ /* r needs to be multiplied by 2 or 2*sqrt(2) depending on LM because
+ short blocks don't have the same energy as long */
+ r = exp2f(1 - Ediff);
+ if (f->size == 3)
+ r *= M_SQRT2;
+ r = FFMIN(thresh, r) * sqrt_1;
+ for (k = 0; k < 1 << f->size; k++) {
+ /* Detect collapse */
+ if (!(block->collapse_masks[i] & 1 << k)) {
+ /* Fill with noise */
+ for (j = 0; j < ff_celt_freq_range[i]; j++)
+ xptr[(j << f->size) + k] = (celt_rng(f) & 0x8000) ? r : -r;
+ renormalize = 1;
+ }
+ }
+
+ /* We just added some energy, so we need to renormalize */
+ if (renormalize)
+ celt_renormalize_vector(xptr, ff_celt_freq_range[i] << f->size, 1.0f);
+ }
+}
+
+int ff_celt_decode_frame(CeltFrame *f, OpusRangeCoder *rc,
+ float **output, int channels, int frame_size,
+ int start_band, int end_band)
+{
+ int i, j, downmix = 0;
+ int consumed; // bits of entropy consumed thus far for this frame
+ AVTXContext *imdct;
+ av_tx_fn imdct_fn;
+
+ if (channels != 1 && channels != 2) {
+ av_log(f->avctx, AV_LOG_ERROR, "Invalid number of coded channels: %d\n",
+ channels);
+ return AVERROR_INVALIDDATA;
+ }
+ if (start_band < 0 || start_band > end_band || end_band > CELT_MAX_BANDS) {
+ av_log(f->avctx, AV_LOG_ERROR, "Invalid start/end band: %d %d\n",
+ start_band, end_band);
+ return AVERROR_INVALIDDATA;
+ }
+
+ f->silence = 0;
+ f->transient = 0;
+ f->anticollapse = 0;
+ f->flushed = 0;
+ f->channels = channels;
+ f->start_band = start_band;
+ f->end_band = end_band;
+ f->framebits = rc->rb.bytes * 8;
+
+ f->size = av_log2(frame_size / CELT_SHORT_BLOCKSIZE);
+ if (f->size > CELT_MAX_LOG_BLOCKS ||
+ frame_size != CELT_SHORT_BLOCKSIZE * (1 << f->size)) {
+ av_log(f->avctx, AV_LOG_ERROR, "Invalid CELT frame size: %d\n",
+ frame_size);
+ return AVERROR_INVALIDDATA;
+ }
+
+ if (!f->output_channels)
+ f->output_channels = channels;
+
+ for (i = 0; i < f->channels; i++) {
+ memset(f->block[i].coeffs, 0, sizeof(f->block[i].coeffs));
+ memset(f->block[i].collapse_masks, 0, sizeof(f->block[i].collapse_masks));
+ }
+
+ consumed = opus_rc_tell(rc);
+
+ /* obtain silence flag */
+ if (consumed >= f->framebits)
+ f->silence = 1;
+ else if (consumed == 1)
+ f->silence = ff_opus_rc_dec_log(rc, 15);
+
+
+ if (f->silence) {
+ consumed = f->framebits;
+ rc->total_bits += f->framebits - opus_rc_tell(rc);
+ }
+
+ /* obtain post-filter options */
+ consumed = parse_postfilter(f, rc, consumed);
+
+ /* obtain transient flag */
+ if (f->size != 0 && consumed+3 <= f->framebits)
+ f->transient = ff_opus_rc_dec_log(rc, 3);
+
+ f->blocks = f->transient ? 1 << f->size : 1;
+ f->blocksize = frame_size / f->blocks;
+
+ imdct = f->tx[f->transient ? 0 : f->size];
+ imdct_fn = f->tx_fn[f->transient ? 0 : f->size];
+
+ if (channels == 1) {
+ for (i = 0; i < CELT_MAX_BANDS; i++)
+ f->block[0].energy[i] = FFMAX(f->block[0].energy[i], f->block[1].energy[i]);
+ }
+
+ celt_decode_coarse_energy(f, rc);
+ celt_decode_tf_changes (f, rc);
+ ff_celt_bitalloc (f, rc, 0);
+ celt_decode_fine_energy (f, rc);
+ ff_celt_quant_bands (f, rc);
+
+ if (f->anticollapse_needed)
+ f->anticollapse = ff_opus_rc_get_raw(rc, 1);
+
+ celt_decode_final_energy(f, rc);
+
+ /* apply anti-collapse processing and denormalization to
+ * each coded channel */
+ for (i = 0; i < f->channels; i++) {
+ CeltBlock *block = &f->block[i];
+
+ if (f->anticollapse)
+ process_anticollapse(f, block, f->block[i].coeffs);
+
+ celt_denormalize(f, block, f->block[i].coeffs);
+ }
+
+ /* stereo -> mono downmix */
+ if (f->output_channels < f->channels) {
+ f->dsp->vector_fmac_scalar(f->block[0].coeffs, f->block[1].coeffs, 1.0, FFALIGN(frame_size, 16));
+ downmix = 1;
+ } else if (f->output_channels > f->channels)
+ memcpy(f->block[1].coeffs, f->block[0].coeffs, frame_size * sizeof(float));
+
+ if (f->silence) {
+ for (i = 0; i < 2; i++) {
+ CeltBlock *block = &f->block[i];
+
+ for (j = 0; j < FF_ARRAY_ELEMS(block->energy); j++)
+ block->energy[j] = CELT_ENERGY_SILENCE;
+ }
+ memset(f->block[0].coeffs, 0, sizeof(f->block[0].coeffs));
+ memset(f->block[1].coeffs, 0, sizeof(f->block[1].coeffs));
+ }
+
+ /* transform and output for each output channel */
+ for (i = 0; i < f->output_channels; i++) {
+ CeltBlock *block = &f->block[i];
+
+ /* iMDCT and overlap-add */
+ for (j = 0; j < f->blocks; j++) {
+ float *dst = block->buf + 1024 + j * f->blocksize;
+
+ imdct_fn(imdct, dst + CELT_OVERLAP / 2, f->block[i].coeffs + j,
+ sizeof(float)*f->blocks);
+ f->dsp->vector_fmul_window(dst, dst, dst + CELT_OVERLAP / 2,
+ ff_celt_window, CELT_OVERLAP / 2);
+ }
+
+ if (downmix)
+ f->dsp->vector_fmul_scalar(&block->buf[1024], &block->buf[1024], 0.5f, frame_size);
+
+ /* postfilter */
+ celt_postfilter(f, block);
+
+ /* deemphasis */
+ block->emph_coeff = f->opusdsp.deemphasis(output[i],
+ &block->buf[1024 - frame_size],
+ block->emph_coeff, frame_size);
+ }
+
+ if (channels == 1)
+ memcpy(f->block[1].energy, f->block[0].energy, sizeof(f->block[0].energy));
+
+ for (i = 0; i < 2; i++ ) {
+ CeltBlock *block = &f->block[i];
+
+ if (!f->transient) {
+ memcpy(block->prev_energy[1], block->prev_energy[0], sizeof(block->prev_energy[0]));
+ memcpy(block->prev_energy[0], block->energy, sizeof(block->prev_energy[0]));
+ } else {
+ for (j = 0; j < CELT_MAX_BANDS; j++)
+ block->prev_energy[0][j] = FFMIN(block->prev_energy[0][j], block->energy[j]);
+ }
+
+ for (j = 0; j < f->start_band; j++) {
+ block->prev_energy[0][j] = CELT_ENERGY_SILENCE;
+ block->energy[j] = 0.0;
+ }
+ for (j = f->end_band; j < CELT_MAX_BANDS; j++) {
+ block->prev_energy[0][j] = CELT_ENERGY_SILENCE;
+ block->energy[j] = 0.0;
+ }
+ }
+
+ f->seed = rc->range;
+
+ return 0;
+}
+
+void ff_celt_flush(CeltFrame *f)
+{
+ int i, j;
+
+ if (f->flushed)
+ return;
+
+ for (i = 0; i < 2; i++) {
+ CeltBlock *block = &f->block[i];
+
+ for (j = 0; j < CELT_MAX_BANDS; j++)
+ block->prev_energy[0][j] = block->prev_energy[1][j] = CELT_ENERGY_SILENCE;
+
+ memset(block->energy, 0, sizeof(block->energy));
+ memset(block->buf, 0, sizeof(block->buf));
+
+ memset(block->pf_gains, 0, sizeof(block->pf_gains));
+ memset(block->pf_gains_old, 0, sizeof(block->pf_gains_old));
+ memset(block->pf_gains_new, 0, sizeof(block->pf_gains_new));
+
+ /* libopus uses CELT_EMPH_COEFF on init, but 0 is better since there's
+ * a lesser discontinuity when seeking.
+ * The deemphasis functions differ from libopus in that they require
+ * an initial state divided by the coefficient. */
+ block->emph_coeff = 0.0f / CELT_EMPH_COEFF;
+ }
+ f->seed = 0;
+
+ f->flushed = 1;
+}
+
+void ff_celt_free(CeltFrame **f)
+{
+ CeltFrame *frm = *f;
+ int i;
+
+ if (!frm)
+ return;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(frm->tx); i++)
+ av_tx_uninit(&frm->tx[i]);
+
+ ff_celt_pvq_uninit(&frm->pvq);
+
+ av_freep(&frm->dsp);
+ av_freep(f);
+}
+
+int ff_celt_init(AVCodecContext *avctx, CeltFrame **f, int output_channels,
+ int apply_phase_inv)
+{
+ CeltFrame *frm;
+ int i, ret;
+
+ if (output_channels != 1 && output_channels != 2) {
+ av_log(avctx, AV_LOG_ERROR, "Invalid number of output channels: %d\n",
+ output_channels);
+ return AVERROR(EINVAL);
+ }
+
+ frm = av_mallocz(sizeof(*frm));
+ if (!frm)
+ return AVERROR(ENOMEM);
+
+ frm->avctx = avctx;
+ frm->output_channels = output_channels;
+ frm->apply_phase_inv = apply_phase_inv;
+
+ for (i = 0; i < FF_ARRAY_ELEMS(frm->tx); i++) {
+ const float scale = -1.0f/32768;
+ if ((ret = av_tx_init(&frm->tx[i], &frm->tx_fn[i], AV_TX_FLOAT_MDCT, 1, 15 << (i + 3), &scale, 0)) < 0)
+ goto fail;
+ }
+
+ if ((ret = ff_celt_pvq_init(&frm->pvq, 0)) < 0)
+ goto fail;
+
+ frm->dsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
+ if (!frm->dsp) {
+ ret = AVERROR(ENOMEM);
+ goto fail;
+ }
+
+ ff_opus_dsp_init(&frm->opusdsp);
+ ff_celt_flush(frm);
+
+ *f = frm;
+
+ return 0;
+fail:
+ ff_celt_free(&frm);
+ return ret;
+}