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115 lines
3.5 KiB
115 lines
3.5 KiB
/* |
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* raw ADTS AAC demuxer |
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* Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at> |
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* Copyright (c) 2009 Robert Swain ( rob opendot cl ) |
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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/intreadwrite.h" |
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#include "avformat.h" |
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#include "internal.h" |
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#include "rawdec.h" |
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#include "id3v1.h" |
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#include "apetag.h" |
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static int adts_aac_probe(AVProbeData *p) |
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{ |
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int max_frames = 0, first_frames = 0; |
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int fsize, frames; |
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const uint8_t *buf0 = p->buf; |
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const uint8_t *buf2; |
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const uint8_t *buf; |
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const uint8_t *end = buf0 + p->buf_size - 7; |
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buf = buf0; |
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for (; buf < end; buf = buf2 + 1) { |
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buf2 = buf; |
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for (frames = 0; buf2 < end; frames++) { |
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uint32_t header = AV_RB16(buf2); |
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if ((header & 0xFFF6) != 0xFFF0) { |
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if (buf != buf0) { |
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// Found something that isn't an ADTS header, starting |
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// from a position other than the start of the buffer. |
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// Discard the count we've accumulated so far since it |
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// probably was a false positive. |
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frames = 0; |
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} |
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break; |
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} |
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fsize = (AV_RB32(buf2 + 3) >> 13) & 0x1FFF; |
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if (fsize < 7) |
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break; |
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fsize = FFMIN(fsize, end - buf2); |
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buf2 += fsize; |
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} |
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max_frames = FFMAX(max_frames, frames); |
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if (buf == buf0) |
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first_frames = frames; |
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} |
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if (first_frames >= 3) |
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return AVPROBE_SCORE_EXTENSION + 1; |
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else if (max_frames > 100) |
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return AVPROBE_SCORE_EXTENSION; |
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else if (max_frames >= 3) |
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return AVPROBE_SCORE_EXTENSION / 2; |
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else if (first_frames >= 1) |
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return 1; |
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else |
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return 0; |
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} |
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static int adts_aac_read_header(AVFormatContext *s) |
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{ |
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AVStream *st; |
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st = avformat_new_stream(s, NULL); |
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if (!st) |
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return AVERROR(ENOMEM); |
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; |
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st->codecpar->codec_id = s->iformat->raw_codec_id; |
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st->need_parsing = AVSTREAM_PARSE_FULL_RAW; |
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ff_id3v1_read(s); |
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if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) && |
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!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX)) { |
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int64_t cur = avio_tell(s->pb); |
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ff_ape_parse_tag(s); |
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avio_seek(s->pb, cur, SEEK_SET); |
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} |
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// LCM of all possible ADTS sample rates |
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avpriv_set_pts_info(st, 64, 1, 28224000); |
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return 0; |
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} |
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AVInputFormat ff_aac_demuxer = { |
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.name = "aac", |
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.long_name = NULL_IF_CONFIG_SMALL("raw ADTS AAC (Advanced Audio Coding)"), |
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.read_probe = adts_aac_probe, |
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.read_header = adts_aac_read_header, |
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.read_packet = ff_raw_read_partial_packet, |
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.flags = AVFMT_GENERIC_INDEX, |
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.extensions = "aac", |
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.mime_type = "audio/aac,audio/aacp,audio/x-aac", |
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.raw_codec_id = AV_CODEC_ID_AAC, |
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};
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