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
38typedef struct MaxisXADemuxContext {
39    uint32_t out_size;
40    uint32_t sent_bytes;
41} MaxisXADemuxContext;
42
43static int xa_probe(AVProbeData *p)
44{
45    int channels, srate, bits_per_sample;
46    if (p->buf_size < 24)
47        return 0;
48    switch(AV_RL32(p->buf)) {
49    case XA00_TAG:
50    case XAI0_TAG:
51    case XAJ0_TAG:
52        break;
53    default:
54        return 0;
55    }
56    channels        = AV_RL16(p->buf + 10);
57    srate           = AV_RL32(p->buf + 12);
58    bits_per_sample = AV_RL16(p->buf + 22);
59    if (!channels || channels > 8 || !srate || srate > 192000 ||
60        bits_per_sample < 4 || bits_per_sample > 32)
61        return 0;
62    return AVPROBE_SCORE_EXTENSION;
63}
64
65static int xa_read_header(AVFormatContext *s)
66{
67    MaxisXADemuxContext *xa = s->priv_data;
68    AVIOContext *pb = s->pb;
69    AVStream *st;
70
71    /*Set up the XA Audio Decoder*/
72    st = avformat_new_stream(s, NULL);
73    if (!st)
74        return AVERROR(ENOMEM);
75
76    st->codec->codec_type   = AVMEDIA_TYPE_AUDIO;
77    st->codec->codec_id     = AV_CODEC_ID_ADPCM_EA_MAXIS_XA;
78    avio_skip(pb, 4);       /* Skip the XA ID */
79    xa->out_size            =  avio_rl32(pb);
80    avio_skip(pb, 2);       /* Skip the tag */
81    st->codec->channels     = avio_rl16(pb);
82    st->codec->sample_rate  = avio_rl32(pb);
83    avio_skip(pb, 4);       /* Skip average byte rate */
84    avio_skip(pb, 2);       /* Skip block align */
85    avio_skip(pb, 2);       /* Skip bits-per-sample */
86
87    if (!st->codec->channels || !st->codec->sample_rate)
88        return AVERROR_INVALIDDATA;
89
90    st->codec->bit_rate = av_clip(15LL * st->codec->channels * 8 *
91                                  st->codec->sample_rate / 28, 0, INT_MAX);
92
93    avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
94    st->start_time = 0;
95
96    return 0;
97}
98
99static int xa_read_packet(AVFormatContext *s,
100                          AVPacket *pkt)
101{
102    MaxisXADemuxContext *xa = s->priv_data;
103    AVStream *st = s->streams[0];
104    AVIOContext *pb = s->pb;
105    unsigned int packet_size;
106    int ret;
107
108    if (xa->sent_bytes >= xa->out_size)
109        return AVERROR_EOF;
110    /* 1 byte header and 14 bytes worth of samples * number channels per block */
111    packet_size = 15*st->codec->channels;
112
113    ret = av_get_packet(pb, pkt, packet_size);
114    if(ret < 0)
115        return ret;
116
117    pkt->stream_index = st->index;
118    xa->sent_bytes += packet_size;
119    pkt->duration = 28;
120
121    return ret;
122}
123
124AVInputFormat 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};
132