1/*
2 * American Laser Games MM Format Demuxer
3 * Copyright (c) 2006 Peter Ross
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 libavformat/mm.c
24 * American Laser Games MM Format Demuxer
25 * by Peter Ross (suxen_drol at hotmail dot com)
26 *
27 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
28 * including Mad Dog McCree and Crime Patrol.
29 *
30 * Technical details here:
31 *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
32 */
33
34#include "libavutil/intreadwrite.h"
35#include "avformat.h"
36
37#define MM_PREAMBLE_SIZE    6
38
39#define MM_TYPE_HEADER      0x0
40#define MM_TYPE_INTER       0x5
41#define MM_TYPE_INTRA       0x8
42#define MM_TYPE_INTRA_HH    0xc
43#define MM_TYPE_INTER_HH    0xd
44#define MM_TYPE_INTRA_HHV   0xe
45#define MM_TYPE_INTER_HHV   0xf
46#define MM_TYPE_AUDIO       0x15
47#define MM_TYPE_PALETTE     0x31
48
49#define MM_HEADER_LEN_V     0x16    /* video only */
50#define MM_HEADER_LEN_AV    0x18    /* video + audio */
51
52#define MM_PALETTE_COUNT    128
53#define MM_PALETTE_SIZE     (MM_PALETTE_COUNT*3)
54
55typedef struct {
56  unsigned int audio_pts, video_pts;
57} MmDemuxContext;
58
59static int mm_probe(AVProbeData *p)
60{
61    /* the first chunk is always the header */
62    if (AV_RL16(&p->buf[0]) != MM_TYPE_HEADER)
63        return 0;
64    if (AV_RL32(&p->buf[2]) != MM_HEADER_LEN_V && AV_RL32(&p->buf[2]) != MM_HEADER_LEN_AV)
65        return 0;
66
67    /* only return half certainty since this check is a bit sketchy */
68    return AVPROBE_SCORE_MAX / 2;
69}
70
71static int mm_read_header(AVFormatContext *s,
72                           AVFormatParameters *ap)
73{
74    MmDemuxContext *mm = s->priv_data;
75    ByteIOContext *pb = s->pb;
76    AVStream *st;
77
78    unsigned int type, length;
79    unsigned int frame_rate, width, height;
80
81    type = get_le16(pb);
82    length = get_le32(pb);
83
84    if (type != MM_TYPE_HEADER)
85        return AVERROR_INVALIDDATA;
86
87    /* read header */
88    get_le16(pb);   /* total number of chunks */
89    frame_rate = get_le16(pb);
90    get_le16(pb);   /* ibm-pc video bios mode */
91    width = get_le16(pb);
92    height = get_le16(pb);
93    url_fseek(pb, length - 10, SEEK_CUR);  /* unknown data */
94
95    /* video stream */
96    st = av_new_stream(s, 0);
97    if (!st)
98        return AVERROR(ENOMEM);
99    st->codec->codec_type = CODEC_TYPE_VIDEO;
100    st->codec->codec_id = CODEC_ID_MMVIDEO;
101    st->codec->codec_tag = 0;  /* no fourcc */
102    st->codec->width = width;
103    st->codec->height = height;
104    av_set_pts_info(st, 64, 1, frame_rate);
105
106    /* audio stream */
107    if (length == MM_HEADER_LEN_AV) {
108        st = av_new_stream(s, 0);
109        if (!st)
110            return AVERROR(ENOMEM);
111        st->codec->codec_type = CODEC_TYPE_AUDIO;
112        st->codec->codec_tag = 0; /* no fourcc */
113        st->codec->codec_id = CODEC_ID_PCM_U8;
114        st->codec->channels = 1;
115        st->codec->sample_rate = 8000;
116        av_set_pts_info(st, 64, 1, 8000); /* 8000 hz */
117    }
118
119    mm->audio_pts = 0;
120    mm->video_pts = 0;
121    return 0;
122}
123
124static int mm_read_packet(AVFormatContext *s,
125                           AVPacket *pkt)
126{
127    MmDemuxContext *mm = s->priv_data;
128    ByteIOContext *pb = s->pb;
129    unsigned char preamble[MM_PREAMBLE_SIZE];
130    unsigned int type, length;
131
132    while(1) {
133
134        if (get_buffer(pb, preamble, MM_PREAMBLE_SIZE) != MM_PREAMBLE_SIZE) {
135            return AVERROR(EIO);
136        }
137
138        type = AV_RL16(&preamble[0]);
139        length = AV_RL16(&preamble[2]);
140
141        switch(type) {
142        case MM_TYPE_PALETTE :
143        case MM_TYPE_INTER :
144        case MM_TYPE_INTRA :
145        case MM_TYPE_INTRA_HH :
146        case MM_TYPE_INTER_HH :
147        case MM_TYPE_INTRA_HHV :
148        case MM_TYPE_INTER_HHV :
149            /* output preamble + data */
150            if (av_new_packet(pkt, length + MM_PREAMBLE_SIZE))
151                return AVERROR(ENOMEM);
152            memcpy(pkt->data, preamble, MM_PREAMBLE_SIZE);
153            if (get_buffer(pb, pkt->data + MM_PREAMBLE_SIZE, length) != length)
154                return AVERROR(EIO);
155            pkt->size = length + MM_PREAMBLE_SIZE;
156            pkt->stream_index = 0;
157            pkt->pts = mm->video_pts;
158            if (type!=MM_TYPE_PALETTE)
159                mm->video_pts++;
160            return 0;
161
162        case MM_TYPE_AUDIO :
163            if (av_get_packet(s->pb, pkt, length)<0)
164                return AVERROR(ENOMEM);
165            pkt->size = length;
166            pkt->stream_index = 1;
167            pkt->pts = mm->audio_pts++;
168            return 0;
169
170        default :
171            av_log(s, AV_LOG_INFO, "unknown chunk type 0x%x\n", type);
172            url_fseek(pb, length, SEEK_CUR);
173        }
174    }
175
176    return 0;
177}
178
179AVInputFormat mm_demuxer = {
180    "mm",
181    NULL_IF_CONFIG_SMALL("American Laser Games MM format"),
182    sizeof(MmDemuxContext),
183    mm_probe,
184    mm_read_header,
185    mm_read_packet,
186};
187