mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
124 lines
3.9 KiB
124 lines
3.9 KiB
/* |
|
* RAW AC-3 and E-AC-3 demuxer |
|
* Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com> |
|
* |
|
* 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 |
|
*/ |
|
|
|
#include "libavutil/crc.h" |
|
#include "libavcodec/ac3_parser.h" |
|
#include "avformat.h" |
|
#include "rawdec.h" |
|
|
|
static int ac3_eac3_probe(AVProbeData *p, enum AVCodecID expected_codec_id) |
|
{ |
|
int max_frames, first_frames = 0, frames; |
|
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++) { |
|
buf2 = buf; |
|
|
|
for(frames = 0; buf2 < end; frames++) { |
|
uint8_t bitstream_id; |
|
uint16_t frame_size; |
|
int ret; |
|
|
|
ret = av_ac3_parse_header(buf2, end - buf2, &bitstream_id, |
|
&frame_size); |
|
if (ret < 0) |
|
break; |
|
if (buf2 + frame_size > end || |
|
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 >= 4) return AVPROBE_SCORE_EXTENSION + 1; |
|
|
|
if (max_frames) { |
|
int pes = 0, i; |
|
unsigned int code = -1; |
|
|
|
#define VIDEO_ID 0x000001e0 |
|
#define AUDIO_ID 0x000001c0 |
|
/* do a search for mpegps headers to be able to properly bias |
|
* towards mpegps if we detect this stream as both. */ |
|
for (i = 0; i<p->buf_size; i++) { |
|
code = (code << 8) + p->buf[i]; |
|
if ((code & 0xffffff00) == 0x100) { |
|
if ((code & 0x1f0) == VIDEO_ID) pes++; |
|
else if((code & 0x1e0) == AUDIO_ID) pes++; |
|
} |
|
} |
|
|
|
if (pes) |
|
max_frames = (max_frames + pes - 1) / pes; |
|
} |
|
if (max_frames > 500) 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(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(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
|
|
|