avcodec: add PCM-DVD encoder

Fixes #6784.

1 files changed, 197 insertions, 0 deletions

diff --git a/libavcodec/pcm-dvdenc.c b/libavcodec/pcm-dvdenc.c
new file mode 100644
index 0000000000..d26eaf071c
--- /dev/null
+++ b/libavcodec/pcm-dvdenc.c
@@ -0,0 +1,197 @@
+/*
+ * LPCM codecs for PCM formats found in Video DVD streams
+ * Copyright (c) 2018 Paul B Mahol
+ *
+ * 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
+ */
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+
+typedef struct PCMDVDContext {
+    uint8_t header[3];       // Header added to every frame
+    int block_size;          // Size of a block of samples in bytes
+    int samples_per_block;   // Number of samples per channel per block
+    int groups_per_block;    // Number of 20/24-bit sample groups per block
+    uint8_t *extra_samples;  // Pointer to leftover samples from a frame
+    int extra_sample_count;  // Number of leftover samples in the buffer
+} PCMDVDContext;
+
+static av_cold int pcm_dvd_encode_init(AVCodecContext *avctx)
+{
+    PCMDVDContext *s = avctx->priv_data;
+    int quant, freq, frame_size;
+
+    switch (avctx->sample_rate) {
+    case 48000:
+        freq = 0;
+        break;
+    case 96000:
+        freq = 1;
+        break;
+    }
+
+    switch (avctx->sample_fmt) {
+    case AV_SAMPLE_FMT_S16:
+        avctx->bits_per_coded_sample = 16;
+        quant = 0;
+        break;
+    case AV_SAMPLE_FMT_S32:
+        avctx->bits_per_coded_sample = 24;
+        quant = 2;
+        break;
+    }
+
+    avctx->bits_per_coded_sample = 16 + quant * 4;
+    avctx->block_align           = avctx->channels * avctx->bits_per_coded_sample / 8;
+    avctx->bit_rate              = avctx->block_align * 8LL * avctx->sample_rate;
+    if (avctx->bit_rate > 9800000) {
+        av_log(avctx, AV_LOG_ERROR, "Too big bitrate: reduce sample rate, bitdepth or channels.\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (avctx->sample_fmt == AV_SAMPLE_FMT_S16) {
+        s->samples_per_block = 1;
+        s->block_size        = avctx->channels * 2;
+        frame_size           = 2008 / s->block_size;
+    } else {
+        switch (avctx->channels) {
+        case 1:
+        case 2:
+        case 4:
+            /* one group has all the samples needed */
+            s->block_size        = 4 * avctx->bits_per_coded_sample / 8;
+            s->samples_per_block = 4 / avctx->channels;
+            s->groups_per_block  = 1;
+            break;
+        case 8:
+            /* two groups have all the samples needed */
+            s->block_size        = 8 * avctx->bits_per_coded_sample / 8;
+            s->samples_per_block = 1;
+            s->groups_per_block  = 2;
+            break;
+        default:
+            /* need avctx->channels groups */
+            s->block_size        = 4 * avctx->channels *
+                                   avctx->bits_per_coded_sample / 8;
+            s->samples_per_block = 4;
+            s->groups_per_block  = avctx->channels;
+            break;
+        }
+
+        frame_size = FFALIGN(2008 / s->block_size, s->samples_per_block);
+    }
+
+    s->header[0] = 0x0c;
+    s->header[1] = (quant << 6) | (freq << 4) | (avctx->channels - 1);
+    s->header[2] = 0x80;
+
+    if (!avctx->frame_size)
+        avctx->frame_size = frame_size;
+
+    return 0;
+}
+
+static int pcm_dvd_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
+                                const AVFrame *frame, int *got_packet_ptr)
+{
+    PCMDVDContext *s = avctx->priv_data;
+    int samples = frame->nb_samples * avctx->channels;
+    int64_t pkt_size = (frame->nb_samples / s->samples_per_block) * s->block_size + 3;
+    int blocks = (pkt_size - 3) / s->block_size;
+    const int16_t *src16;
+    const int32_t *src32;
+    PutByteContext pb;
+    int ret;
+
+    if ((ret = ff_alloc_packet2(avctx, avpkt, pkt_size, 0)) < 0)
+        return ret;
+
+    memcpy(avpkt->data, s->header, 3);
+
+    src16 = (const int16_t *)frame->data[0];
+    src32 = (const int32_t *)frame->data[0];
+
+    bytestream2_init_writer(&pb, avpkt->data + 3, avpkt->size - 3);
+
+    switch (avctx->sample_fmt) {
+    case AV_SAMPLE_FMT_S16:
+        do {
+            bytestream2_put_be16(&pb, *src16++);
+        } while (--samples);
+        break;
+    case AV_SAMPLE_FMT_S32:
+        if (avctx->channels == 1) {
+            do {
+                for (int i = 2; i; i--) {
+                    bytestream2_put_be16(&pb, src32[0] >> 16);
+                    bytestream2_put_be16(&pb, src32[1] >> 16);
+                    bytestream2_put_byte(&pb, (*src32++) >> 24);
+                    bytestream2_put_byte(&pb, (*src32++) >> 24);
+                }
+            } while (--blocks);
+        } else {
+            do {
+                for (int i = s->groups_per_block; i; i--) {
+                    bytestream2_put_be16(&pb, src32[0] >> 16);
+                    bytestream2_put_be16(&pb, src32[1] >> 16);
+                    bytestream2_put_be16(&pb, src32[2] >> 16);
+                    bytestream2_put_be16(&pb, src32[3] >> 16);
+                    bytestream2_put_byte(&pb, (*src32++) >> 24);
+                    bytestream2_put_byte(&pb, (*src32++) >> 24);
+                    bytestream2_put_byte(&pb, (*src32++) >> 24);
+                    bytestream2_put_byte(&pb, (*src32++) >> 24);
+                }
+            } while (--blocks);
+        }
+        break;
+    }
+
+    avpkt->pts      = frame->pts;
+    avpkt->size     = pkt_size;
+    avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
+    *got_packet_ptr = 1;
+
+    return 0;
+}
+
+static av_cold int pcm_dvd_encode_close(AVCodecContext *avctx)
+{
+    return 0;
+}
+
+AVCodec ff_pcm_dvd_encoder = {
+    .name           = "pcm_dvd",
+    .long_name      = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
+    .type           = AVMEDIA_TYPE_AUDIO,
+    .id             = AV_CODEC_ID_PCM_DVD,
+    .priv_data_size = sizeof(PCMDVDContext),
+    .init           = pcm_dvd_encode_init,
+    .close          = pcm_dvd_encode_close,
+    .encode2        = pcm_dvd_encode_frame,
+    .capabilities   = AV_CODEC_CAP_SMALL_LAST_FRAME,
+    .supported_samplerates = (const int[]) { 48000, 96000, 0},
+    .channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_MONO,
+                                            AV_CH_LAYOUT_STEREO,
+                                            AV_CH_LAYOUT_5POINT1,
+                                            AV_CH_LAYOUT_7POINT1,
+                                            0 },
+    .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
+                                                     AV_SAMPLE_FMT_S32,
+                                                     AV_SAMPLE_FMT_NONE },
+};