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/*
* 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;
}
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,
.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 },
};
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