/*
  * Maxis XA (.xa) File Demuxer
  * Copyright (c) 2008 Robert Marston
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file libavformat/xa.c

  * Maxis XA File Demuxer
  * by Robert Marston (rmarston@gmail.com)
  * for more information on the XA audio format see
  *   http://wiki.multimedia.cx/index.php?title=Maxis_XA
  */
 

 #include "libavutil/intreadwrite.h"

 #include "avformat.h"
 
 #define XA00_TAG MKTAG('X', 'A', 0, 0)
 #define XAI0_TAG MKTAG('X', 'A', 'I', 0)
 #define XAJ0_TAG MKTAG('X', 'A', 'J', 0)
 
 typedef struct MaxisXADemuxContext {
     uint32_t out_size;
     uint32_t sent_bytes;
     uint32_t audio_frame_counter;
 } MaxisXADemuxContext;
 
 static int xa_probe(AVProbeData *p)
 {
     switch(AV_RL32(p->buf)) {
     case XA00_TAG:
     case XAI0_TAG:
     case XAJ0_TAG:
         return AVPROBE_SCORE_MAX;
     }
     return 0;
 }
 
 static int xa_read_header(AVFormatContext *s,
                AVFormatParameters *ap)
 {
     MaxisXADemuxContext *xa = s->priv_data;
     ByteIOContext *pb = s->pb;
     AVStream *st;
 
     /*Set up the XA Audio Decoder*/
     st = av_new_stream(s, 0);
     if (!st)
         return AVERROR(ENOMEM);
 
     st->codec->codec_type   = CODEC_TYPE_AUDIO;
     st->codec->codec_id     = CODEC_ID_ADPCM_EA_MAXIS_XA;
     url_fskip(pb, 4);       /* Skip the XA ID */
     xa->out_size            =  get_le32(pb);
     url_fskip(pb, 2);       /* Skip the tag */
     st->codec->channels     = get_le16(pb);
     st->codec->sample_rate  = get_le32(pb);
     /* Value in file is average byte rate*/
     st->codec->bit_rate     = get_le32(pb) * 8;
     st->codec->block_align  = get_le16(pb);

     st->codec->bits_per_coded_sample = get_le16(pb);

 
     av_set_pts_info(st, 64, 1, st->codec->sample_rate);
 
     return 0;
 }
 
 static int xa_read_packet(AVFormatContext *s,
                           AVPacket *pkt)
 {
     MaxisXADemuxContext *xa = s->priv_data;
     AVStream *st = s->streams[0];
     ByteIOContext *pb = s->pb;
     unsigned int packet_size;
     int ret;
 
     if(xa->sent_bytes > xa->out_size)
         return AVERROR(EIO);
     /* 1 byte header and 14 bytes worth of samples * number channels per block */
     packet_size = 15*st->codec->channels;
 
     ret = av_get_packet(pb, pkt, packet_size);
     if(ret != packet_size)
         return AVERROR(EIO);
 
     pkt->stream_index = st->index;
     xa->sent_bytes += packet_size;
     pkt->pts = xa->audio_frame_counter;
     /* 14 bytes Samples per channel with 2 samples per byte */
     xa->audio_frame_counter += 28 * st->codec->channels;
 
     return ret;
 }
 
 AVInputFormat xa_demuxer = {
     "xa",

     NULL_IF_CONFIG_SMALL("Maxis XA File Format"),

     sizeof(MaxisXADemuxContext),
     xa_probe,
     xa_read_header,
     xa_read_packet,
 };