/* * 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 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 "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_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,};