1/* 2 * LOAS AudioSyncStream demuxer 3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at> 4 * 5 * This file is part of FFmpeg. 6 * 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. 11 * 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. 16 * 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 20 */ 21 22#include "libavutil/intreadwrite.h" 23#include "libavutil/internal.h" 24#include "avformat.h" 25#include "internal.h" 26#include "rawdec.h" 27 28#define LOAS_SYNC_WORD 0x2b7 29 30static int loas_probe(AVProbeData *p) 31{ 32 int max_frames = 0, first_frames = 0; 33 int fsize, frames; 34 const uint8_t *buf0 = p->buf; 35 const uint8_t *buf2; 36 const uint8_t *buf; 37 const uint8_t *end = buf0 + p->buf_size - 3; 38 buf = buf0; 39 40 for (; buf < end; buf = buf2 + 1) { 41 buf2 = buf; 42 43 for (frames = 0; buf2 < end; frames++) { 44 uint32_t header = AV_RB24(buf2); 45 if ((header >> 13) != LOAS_SYNC_WORD) 46 break; 47 fsize = (header & 0x1FFF) + 3; 48 if (fsize < 7) 49 break; 50 fsize = FFMIN(fsize, end - buf2); 51 buf2 += fsize; 52 } 53 max_frames = FFMAX(max_frames, frames); 54 if (buf == buf0) 55 first_frames = frames; 56 } 57 58 if (first_frames >= 3) 59 return AVPROBE_SCORE_EXTENSION + 1; 60 else if (max_frames > 100) 61 return AVPROBE_SCORE_EXTENSION; 62 else if (max_frames >= 3) 63 return AVPROBE_SCORE_EXTENSION / 2; 64 else 65 return 0; 66} 67 68static int loas_read_header(AVFormatContext *s) 69{ 70 AVStream *st; 71 72 st = avformat_new_stream(s, NULL); 73 if (!st) 74 return AVERROR(ENOMEM); 75 76 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 77 st->codec->codec_id = s->iformat->raw_codec_id; 78 st->need_parsing = AVSTREAM_PARSE_FULL_RAW; 79 80 //LCM of all possible AAC sample rates 81 avpriv_set_pts_info(st, 64, 1, 28224000); 82 83 return 0; 84} 85 86AVInputFormat ff_loas_demuxer = { 87 .name = "loas", 88 .long_name = NULL_IF_CONFIG_SMALL("LOAS AudioSyncStream"), 89 .read_probe = loas_probe, 90 .read_header = loas_read_header, 91 .read_packet = ff_raw_read_partial_packet, 92 .flags= AVFMT_GENERIC_INDEX, 93 .raw_codec_id = AV_CODEC_ID_AAC_LATM, 94}; 95