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103 lines
3.0 KiB
103 lines
3.0 KiB
/* |
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* RAW AC-3 and E-AC-3 demuxer |
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* Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavutil/crc.h" |
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#include "libavcodec/ac3_parser.h" |
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#include "avformat.h" |
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#include "rawdec.h" |
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static int ac3_eac3_probe(AVProbeData *p, enum CodecID expected_codec_id) |
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{ |
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int max_frames, first_frames = 0, frames; |
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uint8_t *buf, *buf2, *end; |
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AC3HeaderInfo hdr; |
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GetBitContext gbc; |
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enum CodecID codec_id = CODEC_ID_AC3; |
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max_frames = 0; |
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buf = p->buf; |
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end = buf + p->buf_size; |
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for(; buf < end; buf++) { |
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buf2 = buf; |
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for(frames = 0; buf2 < end; frames++) { |
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init_get_bits(&gbc, buf2, 54); |
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if(ff_ac3_parse_header(&gbc, &hdr) < 0) |
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break; |
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if(buf2 + hdr.frame_size > end || |
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av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, buf2 + 2, hdr.frame_size - 2)) |
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break; |
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if (hdr.bitstream_id > 10) |
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codec_id = CODEC_ID_EAC3; |
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buf2 += hdr.frame_size; |
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} |
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max_frames = FFMAX(max_frames, frames); |
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if(buf == p->buf) |
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first_frames = frames; |
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} |
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if(codec_id != expected_codec_id) return 0; |
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// keep this in sync with mp3 probe, both need to avoid |
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// issues with MPEG-files! |
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if (first_frames>=4) return AVPROBE_SCORE_MAX/2+1; |
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else if(max_frames>500)return AVPROBE_SCORE_MAX/2; |
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else if(max_frames>=4) return AVPROBE_SCORE_MAX/4; |
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else if(max_frames>=1) return 1; |
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else return 0; |
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} |
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#if CONFIG_AC3_DEMUXER |
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static int ac3_probe(AVProbeData *p) |
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{ |
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return ac3_eac3_probe(p, CODEC_ID_AC3); |
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} |
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AVInputFormat ff_ac3_demuxer = { |
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"ac3", |
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NULL_IF_CONFIG_SMALL("raw AC-3"), |
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0, |
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ac3_probe, |
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ff_raw_audio_read_header, |
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ff_raw_read_partial_packet, |
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.flags= AVFMT_GENERIC_INDEX, |
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.extensions = "ac3", |
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.value = CODEC_ID_AC3, |
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}; |
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#endif |
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#if CONFIG_EAC3_DEMUXER |
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static int eac3_probe(AVProbeData *p) |
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{ |
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return ac3_eac3_probe(p, CODEC_ID_EAC3); |
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} |
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AVInputFormat ff_eac3_demuxer = { |
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"eac3", |
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NULL_IF_CONFIG_SMALL("raw E-AC-3"), |
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0, |
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eac3_probe, |
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ff_raw_audio_read_header, |
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ff_raw_read_partial_packet, |
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.flags= AVFMT_GENERIC_INDEX, |
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.extensions = "eac3", |
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.value = CODEC_ID_EAC3, |
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}; |
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#endif
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