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FFmpeg/libavcodec/pcm-mpeg.c
Christian Schmidt 4a7429203a pcm-mpeg: correct bitrate calculation 
Bitrate calculation is off since the bluray spec always specifies
an even number of coded channels. This was honored in the decoder,
but not for bitrate calculation.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
2012-10-16 16:03:03 +02:00

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/*
* LPCM codecs for PCM formats found in MPEG streams
* Copyright (c) 2009 Christian Schmidt
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* PCM codecs for encodings found in MPEG streams (DVD/Blu-ray)
*/
#include "libavutil/audioconvert.h"
#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, AV_CH_LAYOUT_MONO, 0, AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_SURROUND,
AV_CH_LAYOUT_2_1, AV_CH_LAYOUT_4POINT0, AV_CH_LAYOUT_2_2, AV_CH_LAYOUT_5POINT0,
AV_CH_LAYOUT_5POINT1, AV_CH_LAYOUT_7POINT0, AV_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)
av_dlog(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, "reserved sample depth (0)\n");
return -1;
}
avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :
AV_SAMPLE_FMT_S32;
avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;
/* get the sample rate. Not all values are used. */
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, "reserved sample rate (%d)\n",
header[2] & 0x0f);
return -1;
}
/*
* get the channel number (and mapping). Not all values are used.
* 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, "reserved channel configuration (%d)\n",
channel_layout);
return -1;
}
avctx->bit_rate = FFALIGN(avctx->channels, 2) * avctx->sample_rate *
avctx->bits_per_coded_sample;
if (avctx->debug & FF_DEBUG_PICT_INFO)
av_dlog(avctx,
"pcm_bluray_parse_header: %d channels, %d bits per sample, %d Hz, %d bit/s\n",
avctx->channels, avctx->bits_per_coded_sample,
avctx->sample_rate, avctx->bit_rate);
return 0;
}
typedef struct PCMBRDecode {
AVFrame frame;
} PCMBRDecode;
static av_cold int pcm_bluray_decode_init(AVCodecContext * avctx)
{
PCMBRDecode *s = avctx->priv_data;
avcodec_get_frame_defaults(&s->frame);
avctx->coded_frame = &s->frame;
return 0;
}
static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
const uint8_t *src = avpkt->data;
int buf_size = avpkt->size;
PCMBRDecode *s = avctx->priv_data;
GetByteContext gb;
int num_source_channels, channel, retval;
int sample_size, samples;
int16_t *dst16;
int32_t *dst32;
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;
bytestream2_init(&gb, src, buf_size);
/* There's always an even number of channels in the source */
num_source_channels = FFALIGN(avctx->channels, 2);
sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;
samples = buf_size / sample_size;
/* get output buffer */
s->frame.nb_samples = samples;
if ((retval = avctx->get_buffer(avctx, &s->frame)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return retval;
}
dst16 = (int16_t *)s->frame.data[0];
dst32 = (int32_t *)s->frame.data[0];
if (samples) {
switch (avctx->channel_layout) {
/* cases with same number of source and coded channels */
case AV_CH_LAYOUT_STEREO:
case AV_CH_LAYOUT_4POINT0:
case AV_CH_LAYOUT_2_2:
samples *= num_source_channels;
if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
#if HAVE_BIGENDIAN
bytestream2_get_buffer(&gb, dst16, buf_size);
#else
do {
*dst16++ = bytestream2_get_be16u(&gb);
} while (--samples);
#endif
} else {
do {
*dst32++ = bytestream2_get_be24u(&gb) << 8;
} while (--samples);
}
break;
/* cases where number of source channels = coded channels + 1 */
case AV_CH_LAYOUT_MONO:
case AV_CH_LAYOUT_SURROUND:
case AV_CH_LAYOUT_2_1:
case AV_CH_LAYOUT_5POINT0:
if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
#if HAVE_BIGENDIAN
bytestream2_get_buffer(&gb, dst16, avctx->channels * 2);
dst16 += avctx->channels;
#else
channel = avctx->channels;
do {
*dst16++ = bytestream2_get_be16u(&gb);
} while (--channel);
#endif
bytestream2_skip(&gb, 2);
} while (--samples);
} else {
do {
channel = avctx->channels;
do {
*dst32++ = bytestream2_get_be24u(&gb) << 8;
} while (--channel);
bytestream2_skip(&gb, 3);
} while (--samples);
}
break;
/* remapping: L, R, C, LBack, RBack, LF */
case AV_CH_LAYOUT_5POINT1:
if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
dst16[0] = bytestream2_get_be16u(&gb);
dst16[1] = bytestream2_get_be16u(&gb);
dst16[2] = bytestream2_get_be16u(&gb);
dst16[4] = bytestream2_get_be16u(&gb);
dst16[5] = bytestream2_get_be16u(&gb);
dst16[3] = bytestream2_get_be16u(&gb);
dst16 += 6;
} while (--samples);
} else {
do {
dst32[0] = bytestream2_get_be24u(&gb) << 8;
dst32[1] = bytestream2_get_be24u(&gb) << 8;
dst32[2] = bytestream2_get_be24u(&gb) << 8;
dst32[4] = bytestream2_get_be24u(&gb) << 8;
dst32[5] = bytestream2_get_be24u(&gb) << 8;
dst32[3] = bytestream2_get_be24u(&gb) << 8;
dst32 += 6;
} while (--samples);
}
break;
/* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
case AV_CH_LAYOUT_7POINT0:
if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
dst16[0] = bytestream2_get_be16u(&gb);
dst16[1] = bytestream2_get_be16u(&gb);
dst16[2] = bytestream2_get_be16u(&gb);
dst16[5] = bytestream2_get_be16u(&gb);
dst16[3] = bytestream2_get_be16u(&gb);
dst16[4] = bytestream2_get_be16u(&gb);
dst16[6] = bytestream2_get_be16u(&gb);
dst16 += 7;
bytestream2_skip(&gb, 2);
} while (--samples);
} else {
do {
dst32[0] = bytestream2_get_be24u(&gb) << 8;
dst32[1] = bytestream2_get_be24u(&gb) << 8;
dst32[2] = bytestream2_get_be24u(&gb) << 8;
dst32[5] = bytestream2_get_be24u(&gb) << 8;
dst32[3] = bytestream2_get_be24u(&gb) << 8;
dst32[4] = bytestream2_get_be24u(&gb) << 8;
dst32[6] = bytestream2_get_be24u(&gb) << 8;
dst32 += 7;
bytestream2_skip(&gb, 3);
} while (--samples);
}
break;
/* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
case AV_CH_LAYOUT_7POINT1:
if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
do {
dst16[0] = bytestream2_get_be16u(&gb);
dst16[1] = bytestream2_get_be16u(&gb);
dst16[2] = bytestream2_get_be16u(&gb);
dst16[6] = bytestream2_get_be16u(&gb);
dst16[4] = bytestream2_get_be16u(&gb);
dst16[5] = bytestream2_get_be16u(&gb);
dst16[7] = bytestream2_get_be16u(&gb);
dst16[3] = bytestream2_get_be16u(&gb);
dst16 += 8;
} while (--samples);
} else {
do {
dst32[0] = bytestream2_get_be24u(&gb) << 8;
dst32[1] = bytestream2_get_be24u(&gb) << 8;
dst32[2] = bytestream2_get_be24u(&gb) << 8;
dst32[6] = bytestream2_get_be24u(&gb) << 8;
dst32[4] = bytestream2_get_be24u(&gb) << 8;
dst32[5] = bytestream2_get_be24u(&gb) << 8;
dst32[7] = bytestream2_get_be24u(&gb) << 8;
dst32[3] = bytestream2_get_be24u(&gb) << 8;
dst32 += 8;
} while (--samples);
}
break;
}
}
*got_frame_ptr = 1;
*(AVFrame *)data = s->frame;
retval = bytestream2_tell(&gb);
if (avctx->debug & FF_DEBUG_BITSTREAM)
av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
retval, buf_size);
return retval + 4;
}
AVCodec ff_pcm_bluray_decoder = {
.name = "pcm_bluray",
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_PCM_BLURAY,
.priv_data_size = sizeof(PCMBRDecode),
.init = pcm_bluray_decode_init,
.decode = pcm_bluray_decode_frame,
.capabilities = CODEC_CAP_DR1,
.sample_fmts = (const enum AVSampleFormat[]){
AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
},
.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
};
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