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/*
* MLP parser
* Copyright (c) 2007 Ian Caulfield
*
* 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
* MLP parser
*/
#include <stdint.h>
#include "libavutil/internal.h"
#include "get_bits.h"
#include "parser.h"
#include "mlp_parse.h"
#include "mlp.h"
typedef struct MLPParseContext
{
ParseContext pc;
int bytes_left;
int in_sync;
int num_substreams;
} MLPParseContext;
static av_cold int mlp_init(AVCodecParserContext *s)
{
ff_mlp_init_crc();
return 0;
}
static int mlp_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
MLPParseContext *mp = s->priv_data;
int sync_present;
uint8_t parity_bits;
int next;
int ret;
int i, p = 0;
s->key_frame = 0;
*poutbuf_size = 0;
*poutbuf = NULL;
if (buf_size == 0)
return 0;
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
next = buf_size;
} else {
if (!mp->in_sync) {
// Not in sync - find a major sync header
for (i = 0; i < buf_size; i++) {
mp->pc.state = (mp->pc.state << 8) | buf[i];
if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&
// ignore if we do not have the data for the start of header
mp->pc.index + i >= 7) {
mp->in_sync = 1;
mp->bytes_left = 0;
break;
}
}
if (!mp->in_sync) {
if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)
av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
return buf_size;
}
if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) {
av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
return ret;
}
return i - 7;
}
if (mp->bytes_left == 0) {
// Find length of this packet
/* Copy overread bytes from last frame into buffer. */
for(; mp->pc.overread>0; mp->pc.overread--) {
mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
}
if (mp->pc.index + buf_size < 2) {
if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)
av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
return buf_size;
}
mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
| (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
if (mp->bytes_left <= 0) { // prevent infinite loop
goto lost_sync;
}
mp->bytes_left -= mp->pc.index;
}
next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
mp->bytes_left -= buf_size;
return buf_size;
}
mp->bytes_left = 0;
}
sync_present = buf_size >= 8 && (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
if (!sync_present) {
/* The first nibble of a frame is a parity check of the 4-byte
* access unit header and all the 2- or 4-byte substream headers. */
// Only check when this isn't a sync frame - syncs have a checksum.
s->key_frame = 0;
parity_bits = 0;
for (i = -1; i < mp->num_substreams; i++) {
parity_bits ^= buf[p++];
parity_bits ^= buf[p++];
if (i < 0 || buf[p-2] & 0x80) {
parity_bits ^= buf[p++];
parity_bits ^= buf[p++];
}
}
if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {
av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");
goto lost_sync;
}
} else {
GetBitContext gb;
MLPHeaderInfo mh;
init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
goto lost_sync;
s->key_frame = 1;
avctx->bits_per_raw_sample = mh.group1_bits;
if (avctx->bits_per_raw_sample > 16)
avctx->sample_fmt = AV_SAMPLE_FMT_S32;
else
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
avctx->sample_rate = mh.group1_samplerate;
avctx->frame_size =
s->duration = mh.access_unit_size;
av_channel_layout_uninit(&avctx->ch_layout);
if (mh.stream_type == 0xbb) {
/* MLP stream */
av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_mlp);
} else { /* mh.stream_type == 0xba */
/* TrueHD stream */
if (!mh.channels_thd_stream2) {
av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream1);
} else {
av_channel_layout_from_mask(&avctx->ch_layout, mh.channel_layout_thd_stream2);
}
}
if (!mh.is_vbr) /* Stream is CBR */
avctx->bit_rate = mh.peak_bitrate;
mp->num_substreams = mh.num_substreams;
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
lost_sync:
mp->in_sync = 0;
return 1;
}
const AVCodecParser ff_mlp_parser = {
.codec_ids = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD },
.priv_data_size = sizeof(MLPParseContext),
.parser_init = mlp_init,
.parser_parse = mlp_parse,
.parser_close = ff_parse_close,
};
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