mirror of
https://git.videolan.org/git/ffmpeg.git
synced 2024-08-28 12:16:12 +02:00
134 lines
4.4 KiB
C
134 lines
4.4 KiB
C
/*
|
|
* RAW AC-3 and E-AC-3 demuxer
|
|
* Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
|
|
*
|
|
* 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 "libavutil/avassert.h"
|
|
#include "libavutil/crc.h"
|
|
#include "libavcodec/ac3_parser.h"
|
|
#include "avformat.h"
|
|
#include "rawdec.h"
|
|
|
|
static int ac3_eac3_probe(const AVProbeData *p, enum AVCodecID expected_codec_id)
|
|
{
|
|
int max_frames, first_frames = 0, frames;
|
|
const uint8_t *buf, *buf2, *end;
|
|
enum AVCodecID codec_id = AV_CODEC_ID_AC3;
|
|
|
|
max_frames = 0;
|
|
buf = p->buf;
|
|
end = buf + p->buf_size;
|
|
|
|
for(; buf < end; buf++) {
|
|
if(buf > p->buf && !(buf[0] == 0x0B && buf[1] == 0x77)
|
|
&& !(buf[0] == 0x77 && buf[1] == 0x0B) )
|
|
continue;
|
|
buf2 = buf;
|
|
|
|
for(frames = 0; buf2 < end; frames++) {
|
|
uint8_t buf3[4096];
|
|
uint8_t bitstream_id;
|
|
uint16_t frame_size;
|
|
int i, ret;
|
|
|
|
if(!memcmp(buf2, "\x1\x10", 2)) {
|
|
if (buf2 + 16 > end)
|
|
break;
|
|
buf2+=16;
|
|
}
|
|
if (buf[0] == 0x77 && buf[1] == 0x0B) {
|
|
for(i=0; i<8; i+=2) {
|
|
buf3[i ] = buf2[i+1];
|
|
buf3[i+1] = buf2[i ];
|
|
}
|
|
ret = av_ac3_parse_header(buf3, 8, &bitstream_id,
|
|
&frame_size);
|
|
}else
|
|
ret = av_ac3_parse_header(buf2, end - buf2, &bitstream_id,
|
|
&frame_size);
|
|
if (ret < 0)
|
|
break;
|
|
if(buf2 + frame_size > end)
|
|
break;
|
|
if (buf[0] == 0x77 && buf[1] == 0x0B) {
|
|
av_assert0(frame_size <= sizeof(buf3));
|
|
for(i = 8; i < frame_size; i += 2) {
|
|
buf3[i ] = buf2[i+1];
|
|
buf3[i+1] = buf2[i ];
|
|
}
|
|
if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf3 + 2, frame_size - 2))
|
|
break;
|
|
} else {
|
|
if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, frame_size - 2))
|
|
break;
|
|
}
|
|
if (bitstream_id > 10)
|
|
codec_id = AV_CODEC_ID_EAC3;
|
|
buf2 += frame_size;
|
|
}
|
|
max_frames = FFMAX(max_frames, frames);
|
|
if(buf == p->buf)
|
|
first_frames = frames;
|
|
}
|
|
if(codec_id != expected_codec_id) return 0;
|
|
// keep this in sync with mp3 probe, both need to avoid
|
|
// issues with MPEG-files!
|
|
if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
|
|
else if(max_frames>200)return AVPROBE_SCORE_EXTENSION;
|
|
else if(max_frames>=4) return AVPROBE_SCORE_EXTENSION/2;
|
|
else if(max_frames>=1) return 1;
|
|
else return 0;
|
|
}
|
|
|
|
#if CONFIG_AC3_DEMUXER
|
|
static int ac3_probe(const AVProbeData *p)
|
|
{
|
|
return ac3_eac3_probe(p, AV_CODEC_ID_AC3);
|
|
}
|
|
|
|
AVInputFormat ff_ac3_demuxer = {
|
|
.name = "ac3",
|
|
.long_name = NULL_IF_CONFIG_SMALL("raw AC-3"),
|
|
.read_probe = ac3_probe,
|
|
.read_header = ff_raw_audio_read_header,
|
|
.read_packet = ff_raw_read_partial_packet,
|
|
.flags= AVFMT_GENERIC_INDEX,
|
|
.extensions = "ac3",
|
|
.raw_codec_id = AV_CODEC_ID_AC3,
|
|
};
|
|
#endif
|
|
|
|
#if CONFIG_EAC3_DEMUXER
|
|
static int eac3_probe(const AVProbeData *p)
|
|
{
|
|
return ac3_eac3_probe(p, AV_CODEC_ID_EAC3);
|
|
}
|
|
|
|
AVInputFormat ff_eac3_demuxer = {
|
|
.name = "eac3",
|
|
.long_name = NULL_IF_CONFIG_SMALL("raw E-AC-3"),
|
|
.read_probe = eac3_probe,
|
|
.read_header = ff_raw_audio_read_header,
|
|
.read_packet = ff_raw_read_partial_packet,
|
|
.flags = AVFMT_GENERIC_INDEX,
|
|
.extensions = "eac3",
|
|
.raw_codec_id = AV_CODEC_ID_EAC3,
|
|
};
|
|
#endif
|