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(const 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 ch, i; 38 ch = p->buf[264]; 39 40 if (ch != 1 && ch != 2) 41 return 0; 42 43 /* Check so that the redundant bsm bytes and info bytes are valid 44 * the block size mode bytes have to be the same 45 * the info bytes have to be the same 46 */ 47 for (i = 2048; i + 211 < p->buf_size; i+= 212) { 48 int bsm_s, bsm_e, inb_s, inb_e; 49 bsm_s = p->buf[0]; 50 inb_s = p->buf[1]; 51 inb_e = p->buf[210]; 52 bsm_e = p->buf[211]; 53 54 if (bsm_s != bsm_e || inb_s != inb_e) 55 return 0; 56 } 57 return AVPROBE_SCORE_MAX / 4 + 1; 58 } 59 return 0; 60} 61 62static int aea_read_header(AVFormatContext *s) 63{ 64 AVStream *st = avformat_new_stream(s, NULL); 65 int channels; 66 if (!st) 67 return AVERROR(ENOMEM); 68 69 /* Parse the amount of channels and skip to pos 2048(0x800) */ 70 avio_skip(s->pb, 264); 71 channels = avio_r8(s->pb); 72 avio_skip(s->pb, 1783); 73 74 75 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; 76 st->codecpar->codec_id = AV_CODEC_ID_ATRAC1; 77 st->codecpar->sample_rate = 44100; 78 st->codecpar->bit_rate = 292000; 79 80 if (channels != 1 && channels != 2) { 81 av_log(s, AV_LOG_ERROR, "Channels %d not supported!\n", channels); 82 return AVERROR_INVALIDDATA; 83 } 84 85 av_channel_layout_default(&st->codecpar->ch_layout, channels); 86 87 st->codecpar->block_align = AT1_SU_SIZE * st->codecpar->ch_layout.nb_channels; 88 return 0; 89} 90 91static int aea_read_packet(AVFormatContext *s, AVPacket *pkt) 92{ 93 int ret = av_get_packet(s->pb, pkt, s->streams[0]->codecpar->block_align); 94 95 pkt->stream_index = 0; 96 if (ret <= 0) 97 return AVERROR(EIO); 98 99 return ret; 100} 101 102const AVInputFormat ff_aea_demuxer = { 103 .name = "aea", 104 .long_name = NULL_IF_CONFIG_SMALL("MD STUDIO audio"), 105 .read_probe = aea_read_probe, 106 .read_header = aea_read_header, 107 .read_packet = aea_read_packet, 108 .read_seek = ff_pcm_read_seek, 109 .flags = AVFMT_GENERIC_INDEX, 110 .extensions = "aea", 111}; 112