2 * RAW AC-3 and E-AC-3 demuxer
3 * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "config_components.h"
24 #include "libavutil/avassert.h"
25 #include "libavutil/crc.h"
26 #include "libavcodec/ac3_parser.h"
30 static int ac3_eac3_probe(const AVProbeData *p, enum AVCodecID expected_codec_id)
32 int max_frames, first_frames = 0, frames;
33 const uint8_t *buf, *buf2, *end;
34 enum AVCodecID codec_id = AV_CODEC_ID_AC3;
38 end = buf + p->buf_size;
40 for(; buf < end; buf++) {
41 if(buf > p->buf && !(buf[0] == 0x0B && buf[1] == 0x77)
42 && !(buf[0] == 0x77 && buf[1] == 0x0B) )
46 for(frames = 0; buf2 < end; frames++) {
52 if(!memcmp(buf2, "\x1\x10", 2)) {
57 if (buf[0] == 0x77 && buf[1] == 0x0B) {
62 ret = av_ac3_parse_header(buf3, 8, &bitstream_id,
65 ret = av_ac3_parse_header(buf2, end - buf2, &bitstream_id,
69 if(buf2 + frame_size > end)
71 if (buf[0] == 0x77 && buf[1] == 0x0B) {
72 av_assert0(frame_size <= sizeof(buf3));
73 for(i = 8; i < frame_size; i += 2) {
77 if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf3 + 2, frame_size - 2))
80 if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, frame_size - 2))
83 if (bitstream_id > 10)
84 codec_id = AV_CODEC_ID_EAC3;
87 max_frames = FFMAX(max_frames, frames);
89 first_frames = frames;
91 if(codec_id != expected_codec_id) return 0;
92 // keep this in sync with mp3 probe, both need to avoid
93 // issues with MPEG-files!
94 if (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
95 else if(max_frames>200)return AVPROBE_SCORE_EXTENSION;
96 else if(max_frames>=4) return AVPROBE_SCORE_EXTENSION/2;
97 else if(max_frames>=1) return 1;
101 #if CONFIG_AC3_DEMUXER
102 static int ac3_probe(const AVProbeData *p)
104 return ac3_eac3_probe(p, AV_CODEC_ID_AC3);
107 const AVInputFormat ff_ac3_demuxer = {
109 .long_name = NULL_IF_CONFIG_SMALL("raw AC-3"),
110 .read_probe = ac3_probe,
111 .read_header = ff_raw_audio_read_header,
112 .read_packet = ff_raw_read_partial_packet,
113 .flags= AVFMT_GENERIC_INDEX,
115 .raw_codec_id = AV_CODEC_ID_AC3,
116 .priv_data_size = sizeof(FFRawDemuxerContext),
117 .priv_class = &ff_raw_demuxer_class,
121 #if CONFIG_EAC3_DEMUXER
122 static int eac3_probe(const AVProbeData *p)
124 return ac3_eac3_probe(p, AV_CODEC_ID_EAC3);
127 const AVInputFormat ff_eac3_demuxer = {
129 .long_name = NULL_IF_CONFIG_SMALL("raw E-AC-3"),
130 .read_probe = eac3_probe,
131 .read_header = ff_raw_audio_read_header,
132 .read_packet = ff_raw_read_partial_packet,
133 .flags = AVFMT_GENERIC_INDEX,
134 .extensions = "eac3",
135 .raw_codec_id = AV_CODEC_ID_EAC3,
136 .priv_data_size = sizeof(FFRawDemuxerContext),
137 .priv_class = &ff_raw_demuxer_class,