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FFmpeg/libavcodec/pcm-mpeg.c

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/*
* LPCM codecs for PCM formats found in MPEG streams
* Copyright (c) 2009 Christian Schmidt
*
* 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 libavcodec/pcm-mpeg.c
* PCM codecs for encodings found in MPEG streams (DVD/Blu-ray)
*/
#include "avcodec.h"
#include "bytestream.h"
/*
* Channel Mapping according to
* Blu-ray Disc Read-Only Format Version 1
* Part 3: Audio Visual Basic Specifications
* mono M1 X
* stereo L R
* 3/0 L R C X
* 2/1 L R S X
* 3/1 L R C S
* 2/2 L R LS RS
* 3/2 L R C LS RS X
* 3/2+lfe L R C LS RS lfe
* 3/4 L R C LS Rls Rrs RS X
* 3/4+lfe L R C LS Rls Rrs RS lfe
*/
/**
* Parse the header of a LPCM frame read from a MPEG-TS stream
* @param avctx the codec context
* @param header pointer to the first four bytes of the data packet
*/
static int pcm_bluray_parse_header(AVCodecContext *avctx,
const uint8_t *header)
{
static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
static const uint32_t channel_layouts[16] = {
0, CH_LAYOUT_MONO, 0, CH_LAYOUT_STEREO, CH_LAYOUT_SURROUND,
CH_LAYOUT_2_1, CH_LAYOUT_4POINT0, CH_LAYOUT_2_2, CH_LAYOUT_5POINT0,
CH_LAYOUT_5POINT1, CH_LAYOUT_7POINT0, CH_LAYOUT_7POINT1, 0, 0, 0, 0
};
static const uint8_t channels[16] = {
0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
};
uint8_t channel_layout = header[2] >> 4;
if (avctx->debug & FF_DEBUG_PICT_INFO)
dprintf(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
header[0], header[1], header[2], header[3]);
/* get the sample depth and derive the sample format from it */
avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
if (!avctx->bits_per_coded_sample) {
av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (0)\n");
return -1;
}
avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? SAMPLE_FMT_S16 :
SAMPLE_FMT_S32;
/* get the sample rate. Not all values are known or exist. */
switch (header[2] & 0x0f) {
case 1:
avctx->sample_rate = 48000;
break;
case 4:
avctx->sample_rate = 96000;
break;
case 5:
avctx->sample_rate = 192000;
break;
default:
avctx->sample_rate = 0;
av_log(avctx, AV_LOG_ERROR, "unsupported sample rate (%d)\n",
header[2] & 0x0f);
return -1;
}
/*
* get the channel number (and mapping). Not all values are known or exist.
* It must be noted that the number of channels in the MPEG stream can
* differ from the actual meaningful number, e.g. mono audio still has two
* channels, one being empty.
*/
avctx->channel_layout = channel_layouts[channel_layout];
avctx->channels = channels[channel_layout];
if (!avctx->channels) {
av_log(avctx, AV_LOG_ERROR, "unsupported channel configuration (%d)\n",
channel_layout);
return -1;
}
avctx->bit_rate = avctx->channels * avctx->sample_rate *
avctx->bits_per_coded_sample;
if (avctx->debug & FF_DEBUG_PICT_INFO)
dprintf(avctx,
"pcm_bluray_parse_header: %d channels, %d bits per sample, %d kHz, %d kbit\n",
avctx->channels, avctx->bits_per_coded_sample,
avctx->sample_rate, avctx->bit_rate);
return 0;
}
static int pcm_bluray_decode_frame(AVCodecContext *avctx,
void *data,
int *data_size,
AVPacket *avpkt)
{
const uint8_t *src = avpkt->data;
int buf_size = avpkt->size;
int num_source_channels, channel, retval;
int sample_size, samples, output_size;
int16_t *dst16 = data;
int32_t *dst32 = data;
if (buf_size < 4) {
av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
return -1;
}
if (pcm_bluray_parse_header(avctx, src))
return -1;
src += 4;
buf_size -= 4;
/* There's always an even number of channels in the source */
num_source_channels = FFALIGN(avctx->channels, 2);
sample_size = (num_source_channels * avctx->bits_per_coded_sample) >> 3;
samples = buf_size / sample_size;
output_size = samples * avctx->channels *
(avctx->sample_fmt == SAMPLE_FMT_S32 ? 4 : 2);
if (output_size > *data_size) {
av_log(avctx, AV_LOG_ERROR,
"Insufficient output buffer space (%d bytes, needed %d bytes)\n",
*data_size, output_size);
return -1;
}
*data_size = output_size;
if (samples) {
switch (avctx->channel_layout) {
/* cases with same number of source and coded channels */
case CH_LAYOUT_STEREO:
case CH_LAYOUT_4POINT0:
case CH_LAYOUT_2_2:
samples *= num_source_channels;
if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
#if HAVE_BIGENDIAN
memcpy(dst16, src, output_size);
#else
do {
*dst16++ = bytestream_get_be16(&src);
} while (--samples);
#endif
} else {
do {
*dst32++ = bytestream_get_be24(&src) << 8;
} while (--samples);
}
break;
/* cases where number of source channels = coded channels + 1 */
case CH_LAYOUT_MONO:
case CH_LAYOUT_SURROUND:
case CH_LAYOUT_2_1:
case CH_LAYOUT_5POINT0:
if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
#if HAVE_BIGENDIAN
memcpy(dst16, src, avctx->channels * 2);
dst16 += avctx->channels;
src += sample_size;
#else
channel = avctx->channels;
do {
*dst16++ = bytestream_get_be16(&src);
} while (--channel);
src += 2;
#endif
} while (--samples);
} else {
do {
channel = avctx->channels;
do {
*dst32++ = bytestream_get_be24(&src) << 8;
} while (--channel);
src += 3;
} while (--samples);
}
break;
/* remapping: L, R, C, LBack, RBack, LF */
case CH_LAYOUT_5POINT1:
if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
dst16[0] = bytestream_get_be16(&src);
dst16[1] = bytestream_get_be16(&src);
dst16[2] = bytestream_get_be16(&src);
dst16[4] = bytestream_get_be16(&src);
dst16[5] = bytestream_get_be16(&src);
dst16[3] = bytestream_get_be16(&src);
dst16 += 6;
} while (--samples);
} else {
do {
dst32[0] = bytestream_get_be24(&src) << 8;
dst32[1] = bytestream_get_be24(&src) << 8;
dst32[2] = bytestream_get_be24(&src) << 8;
dst32[4] = bytestream_get_be24(&src) << 8;
dst32[5] = bytestream_get_be24(&src) << 8;
dst32[3] = bytestream_get_be24(&src) << 8;
dst32 += 6;
} while (--samples);
}
break;
/* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
case CH_LAYOUT_7POINT0:
if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
dst16[0] = bytestream_get_be16(&src);
dst16[1] = bytestream_get_be16(&src);
dst16[2] = bytestream_get_be16(&src);
dst16[5] = bytestream_get_be16(&src);
dst16[3] = bytestream_get_be16(&src);
dst16[4] = bytestream_get_be16(&src);
dst16[6] = bytestream_get_be16(&src);
dst16 += 7;
src += 2;
} while (--samples);
} else {
do {
dst32[0] = bytestream_get_be24(&src) << 8;
dst32[1] = bytestream_get_be24(&src) << 8;
dst32[2] = bytestream_get_be24(&src) << 8;
dst32[5] = bytestream_get_be24(&src) << 8;
dst32[3] = bytestream_get_be24(&src) << 8;
dst32[4] = bytestream_get_be24(&src) << 8;
dst32[6] = bytestream_get_be24(&src) << 8;
dst32 += 7;
src += 3;
} while (--samples);
}
break;
/* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
case CH_LAYOUT_7POINT1:
if (SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
dst16[0] = bytestream_get_be16(&src);
dst16[1] = bytestream_get_be16(&src);
dst16[2] = bytestream_get_be16(&src);
dst16[6] = bytestream_get_be16(&src);
dst16[4] = bytestream_get_be16(&src);
dst16[5] = bytestream_get_be16(&src);
dst16[7] = bytestream_get_be16(&src);
dst16[3] = bytestream_get_be16(&src);
dst16 += 8;
} while (--samples);
} else {
do {
dst32[0] = bytestream_get_be24(&src) << 8;
dst32[1] = bytestream_get_be24(&src) << 8;
dst32[2] = bytestream_get_be24(&src) << 8;
dst32[6] = bytestream_get_be24(&src) << 8;
dst32[4] = bytestream_get_be24(&src) << 8;
dst32[5] = bytestream_get_be24(&src) << 8;
dst32[7] = bytestream_get_be24(&src) << 8;
dst32[3] = bytestream_get_be24(&src) << 8;
dst32 += 8;
} while (--samples);
}
break;
}
}
retval = src - avpkt->data;
if (avctx->debug & FF_DEBUG_BITSTREAM)
dprintf(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
retval, *data_size);
return retval;
}
AVCodec pcm_bluray_decoder = {
"pcm_bluray",
AVMEDIA_TYPE_AUDIO,
CODEC_ID_PCM_BLURAY,
0,
NULL,
NULL,
NULL,
pcm_bluray_decode_frame,
.sample_fmts = (const enum SampleFormat[]){SAMPLE_FMT_S16, SAMPLE_FMT_S32,
SAMPLE_FMT_NONE},
.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
};