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Diffstat (limited to 'ffmpeg/libavformat/ac3dec.c')
| -rw-r--r-- | ffmpeg/libavformat/ac3dec.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/ffmpeg/libavformat/ac3dec.c b/ffmpeg/libavformat/ac3dec.c new file mode 100644 index 0000000..c531f8a --- /dev/null +++ b/ffmpeg/libavformat/ac3dec.c @@ -0,0 +1,123 @@ +/* + * 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/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; + const uint8_t *buf, *buf2, *end; + AC3HeaderInfo hdr; + GetBitContext gbc; + 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]; + int i; + if(!memcmp(buf2, "\x1\x10\0\0\0\0\0\0", 8)) + buf2+=16; + if (buf[0] == 0x77 && buf[1] == 0x0B) { + for(i=0; i<8; i+=2) { + buf3[i ] = buf[i+1]; + buf3[i+1] = buf[i ]; + } + init_get_bits(&gbc, buf3, 54); + }else + init_get_bits(&gbc, buf2, 54); + if(avpriv_ac3_parse_header(&gbc, &hdr) < 0) + break; + if(buf2 + hdr.frame_size > end) + break; + if (buf[0] == 0x77 && buf[1] == 0x0B) { + av_assert0(hdr.frame_size <= sizeof(buf3)); + for(i=8; i<hdr.frame_size; i+=2) { + buf3[i ] = buf[i+1]; + buf3[i+1] = buf[i ]; + } + } + if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, gbc.buffer + 2, hdr.frame_size - 2)) + break; + if (hdr.bitstream_id > 10) + codec_id = AV_CODEC_ID_EAC3; + buf2 += hdr.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_MAX/2+1; + else if(max_frames>200)return AVPROBE_SCORE_MAX/2; + else if(max_frames>=4) return AVPROBE_SCORE_MAX/4; + 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 |