Line data    Source code

       1             : /*
       2             :  * Maxis XA (.xa) File Demuxer
       3             :  * Copyright (c) 2008 Robert Marston
       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             : /**
      23             :  * @file
      24             :  * Maxis XA File Demuxer
      25             :  * by Robert Marston (rmarston@gmail.com)
      26             :  * for more information on the XA audio format see
      27             :  *   http://wiki.multimedia.cx/index.php?title=Maxis_XA
      28             :  */
      29             : 
      30             : #include "libavutil/intreadwrite.h"
      31             : #include "avformat.h"
      32             : #include "internal.h"
      33             : 
      34             : #define XA00_TAG MKTAG('X', 'A', 0, 0)
      35             : #define XAI0_TAG MKTAG('X', 'A', 'I', 0)
      36             : #define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
      37             : 
      38             : typedef struct MaxisXADemuxContext {
      39             :     uint32_t out_size;
      40             :     uint32_t sent_bytes;
      41             : } MaxisXADemuxContext;
      42             : 
      43        6217 : static int xa_probe(AVProbeData *p)
      44             : {
      45             :     int channels, srate, bits_per_sample;
      46        6217 :     if (p->buf_size < 24)
      47           0 :         return 0;
      48        6217 :     switch(AV_RL32(p->buf)) {
      49           2 :     case XA00_TAG:
      50             :     case XAI0_TAG:
      51             :     case XAJ0_TAG:
      52           2 :         break;
      53        6215 :     default:
      54        6215 :         return 0;
      55             :     }
      56           2 :     channels        = AV_RL16(p->buf + 10);
      57           2 :     srate           = AV_RL32(p->buf + 12);
      58           2 :     bits_per_sample = AV_RL16(p->buf + 22);
      59           2 :     if (!channels || channels > 8 || !srate || srate > 192000 ||
      60           2 :         bits_per_sample < 4 || bits_per_sample > 32)
      61           0 :         return 0;
      62           2 :     return AVPROBE_SCORE_EXTENSION;
      63             : }
      64             : 
      65           2 : static int xa_read_header(AVFormatContext *s)
      66             : {
      67           2 :     MaxisXADemuxContext *xa = s->priv_data;
      68           2 :     AVIOContext *pb = s->pb;
      69             :     AVStream *st;
      70             : 
      71             :     /*Set up the XA Audio Decoder*/
      72           2 :     st = avformat_new_stream(s, NULL);
      73           2 :     if (!st)
      74           0 :         return AVERROR(ENOMEM);
      75             : 
      76           2 :     st->codecpar->codec_type   = AVMEDIA_TYPE_AUDIO;
      77           2 :     st->codecpar->codec_id     = AV_CODEC_ID_ADPCM_EA_MAXIS_XA;
      78           2 :     avio_skip(pb, 4);       /* Skip the XA ID */
      79           2 :     xa->out_size            =  avio_rl32(pb);
      80           2 :     avio_skip(pb, 2);       /* Skip the tag */
      81           2 :     st->codecpar->channels     = avio_rl16(pb);
      82           2 :     st->codecpar->sample_rate  = avio_rl32(pb);
      83           2 :     avio_skip(pb, 4);       /* Skip average byte rate */
      84           2 :     avio_skip(pb, 2);       /* Skip block align */
      85           2 :     avio_skip(pb, 2);       /* Skip bits-per-sample */
      86             : 
      87           2 :     if (!st->codecpar->channels || !st->codecpar->sample_rate)
      88           0 :         return AVERROR_INVALIDDATA;
      89             : 
      90           6 :     st->codecpar->bit_rate = av_clip(15LL * st->codecpar->channels * 8 *
      91           4 :                                   st->codecpar->sample_rate / 28, 0, INT_MAX);
      92             : 
      93           2 :     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
      94           2 :     st->start_time = 0;
      95             : 
      96           2 :     return 0;
      97             : }
      98             : 
      99         100 : static int xa_read_packet(AVFormatContext *s,
     100             :                           AVPacket *pkt)
     101             : {
     102         100 :     MaxisXADemuxContext *xa = s->priv_data;
     103         100 :     AVStream *st = s->streams[0];
     104         100 :     AVIOContext *pb = s->pb;
     105             :     unsigned int packet_size;
     106             :     int ret;
     107             : 
     108         100 :     if (xa->sent_bytes >= xa->out_size)
     109           0 :         return AVERROR_EOF;
     110             :     /* 1 byte header and 14 bytes worth of samples * number channels per block */
     111         100 :     packet_size = 15*st->codecpar->channels;
     112             : 
     113         100 :     ret = av_get_packet(pb, pkt, packet_size);
     114         100 :     if(ret < 0)
     115           0 :         return ret;
     116             : 
     117         100 :     pkt->stream_index = st->index;
     118         100 :     xa->sent_bytes += packet_size;
     119         100 :     pkt->duration = 28;
     120             : 
     121         100 :     return ret;
     122             : }
     123             : 
     124             : AVInputFormat ff_xa_demuxer = {
     125             :     .name           = "xa",
     126             :     .long_name      = NULL_IF_CONFIG_SMALL("Maxis XA"),
     127             :     .priv_data_size = sizeof(MaxisXADemuxContext),
     128             :     .read_probe     = xa_probe,
     129             :     .read_header    = xa_read_header,
     130             :     .read_packet    = xa_read_packet,
     131             : };