1/* 2 * MD STUDIO audio demuxer 3 * 4 * Copyright (c) 2009 Benjamin Larsson 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23#include "libavutil/channel_layout.h" 24#include "libavutil/intreadwrite.h" 25#include "avformat.h" 26#include "pcm.h" 27 28#define AT1_SU_SIZE 212 29 30static int aea_read_probe(AVProbeData *p) 31{ 32 if (p->buf_size <= 2048+212) 33 return 0; 34 35 /* Magic is '00 08 00 00' in Little Endian*/ 36 if (AV_RL32(p->buf)==0x800) { 37 int bsm_s, bsm_e, inb_s, inb_e, ch; 38 ch = p->buf[264]; 39 bsm_s = p->buf[2048]; 40 inb_s = p->buf[2048+1]; 41 inb_e = p->buf[2048+210]; 42 bsm_e = p->buf[2048+211]; 43 44 if (ch != 1 && ch != 2) 45 return 0; 46 47 /* Check so that the redundant bsm bytes and info bytes are valid 48 * the block size mode bytes have to be the same 49 * the info bytes have to be the same 50 */ 51 if (bsm_s == bsm_e && inb_s == inb_e) 52 return AVPROBE_SCORE_MAX / 4 + 1; 53 } 54 return 0; 55} 56 57static int aea_read_header(AVFormatContext *s) 58{ 59 AVStream *st = avformat_new_stream(s, NULL); 60 if (!st) 61 return AVERROR(ENOMEM); 62 63 /* Parse the amount of channels and skip to pos 2048(0x800) */ 64 avio_skip(s->pb, 264); 65 st->codec->channels = avio_r8(s->pb); 66 avio_skip(s->pb, 1783); 67 68 69 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 70 st->codec->codec_id = AV_CODEC_ID_ATRAC1; 71 st->codec->sample_rate = 44100; 72 st->codec->bit_rate = 292000; 73 74 if (st->codec->channels != 1 && st->codec->channels != 2) { 75 av_log(s,AV_LOG_ERROR,"Channels %d not supported!\n",st->codec->channels); 76 return -1; 77 } 78 79 st->codec->channel_layout = (st->codec->channels == 1) ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO; 80 81 st->codec->block_align = AT1_SU_SIZE * st->codec->channels; 82 return 0; 83} 84 85static int aea_read_packet(AVFormatContext *s, AVPacket *pkt) 86{ 87 int ret = av_get_packet(s->pb, pkt, s->streams[0]->codec->block_align); 88 89 pkt->stream_index = 0; 90 if (ret <= 0) 91 return AVERROR(EIO); 92 93 return ret; 94} 95 96AVInputFormat ff_aea_demuxer = { 97 .name = "aea", 98 .long_name = NULL_IF_CONFIG_SMALL("MD STUDIO audio"), 99 .read_probe = aea_read_probe, 100 .read_header = aea_read_header, 101 .read_packet = aea_read_packet, 102 .read_seek = ff_pcm_read_seek, 103 .flags = AVFMT_GENERIC_INDEX, 104 .extensions = "aea", 105}; 106