1/*
2 * 8088flex TMV file demuxer
3 * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
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 * 8088flex TMV file demuxer
25 * @author Daniel Verkamp
26 * @see http://www.oldskool.org/pc/8088_Corruption
27 */
28
29#include "libavutil/channel_layout.h"
30#include "libavutil/intreadwrite.h"
31#include "avformat.h"
32#include "internal.h"
33
34enum {
35    TMV_PADDING = 0x01,
36    TMV_STEREO  = 0x02,
37};
38
39#define TMV_TAG MKTAG('T', 'M', 'A', 'V')
40
41typedef struct TMVContext {
42    unsigned audio_chunk_size;
43    unsigned video_chunk_size;
44    unsigned padding;
45    unsigned stream_index;
46} TMVContext;
47
48#define TMV_HEADER_SIZE       12
49
50#define PROBE_MIN_SAMPLE_RATE 5000
51#define PROBE_MAX_FPS         120
52#define PROBE_MIN_AUDIO_SIZE  (PROBE_MIN_SAMPLE_RATE / PROBE_MAX_FPS)
53
54static int tmv_probe(AVProbeData *p)
55{
56    if (AV_RL32(p->buf)   == TMV_TAG &&
57        AV_RL16(p->buf+4) >= PROBE_MIN_SAMPLE_RATE &&
58        AV_RL16(p->buf+6) >= PROBE_MIN_AUDIO_SIZE  &&
59               !p->buf[8] && // compression method
60                p->buf[9] && // char cols
61                p->buf[10])  // char rows
62        return AVPROBE_SCORE_MAX /
63            ((p->buf[9] == 40 && p->buf[10] == 25) ? 1 : 4);
64    return 0;
65}
66
67static int tmv_read_header(AVFormatContext *s)
68{
69    TMVContext *tmv   = s->priv_data;
70    AVIOContext *pb = s->pb;
71    AVStream *vst, *ast;
72    AVRational fps;
73    unsigned comp_method, char_cols, char_rows, features;
74
75    if (avio_rl32(pb) != TMV_TAG)
76        return -1;
77
78    if (!(vst = avformat_new_stream(s, NULL)))
79        return AVERROR(ENOMEM);
80
81    if (!(ast = avformat_new_stream(s, NULL)))
82        return AVERROR(ENOMEM);
83
84    ast->codec->sample_rate = avio_rl16(pb);
85    if (!ast->codec->sample_rate) {
86        av_log(s, AV_LOG_ERROR, "invalid sample rate\n");
87        return -1;
88    }
89
90    tmv->audio_chunk_size   = avio_rl16(pb);
91    if (!tmv->audio_chunk_size) {
92        av_log(s, AV_LOG_ERROR, "invalid audio chunk size\n");
93        return -1;
94    }
95
96    comp_method             = avio_r8(pb);
97    if (comp_method) {
98        av_log(s, AV_LOG_ERROR, "unsupported compression method %d\n",
99               comp_method);
100        return -1;
101    }
102
103    char_cols = avio_r8(pb);
104    char_rows = avio_r8(pb);
105    tmv->video_chunk_size = char_cols * char_rows * 2;
106
107    features  = avio_r8(pb);
108    if (features & ~(TMV_PADDING | TMV_STEREO)) {
109        av_log(s, AV_LOG_ERROR, "unsupported features 0x%02x\n",
110               features & ~(TMV_PADDING | TMV_STEREO));
111        return -1;
112    }
113
114    ast->codec->codec_type            = AVMEDIA_TYPE_AUDIO;
115    ast->codec->codec_id              = AV_CODEC_ID_PCM_U8;
116    if (features & TMV_STEREO) {
117        ast->codec->channels       = 2;
118        ast->codec->channel_layout = AV_CH_LAYOUT_STEREO;
119    } else {
120        ast->codec->channels       = 1;
121        ast->codec->channel_layout = AV_CH_LAYOUT_MONO;
122    }
123    ast->codec->bits_per_coded_sample = 8;
124    ast->codec->bit_rate              = ast->codec->sample_rate *
125                                        ast->codec->bits_per_coded_sample;
126    avpriv_set_pts_info(ast, 32, 1, ast->codec->sample_rate);
127
128    fps.num = ast->codec->sample_rate * ast->codec->channels;
129    fps.den = tmv->audio_chunk_size;
130    av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
131
132    vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;
133    vst->codec->codec_id   = AV_CODEC_ID_TMV;
134    vst->codec->pix_fmt    = AV_PIX_FMT_PAL8;
135    vst->codec->width      = char_cols * 8;
136    vst->codec->height     = char_rows * 8;
137    avpriv_set_pts_info(vst, 32, fps.den, fps.num);
138
139    if (features & TMV_PADDING)
140        tmv->padding =
141            ((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
142             (tmv->video_chunk_size + tmv->audio_chunk_size);
143
144    vst->codec->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
145                            fps.num * 8) / fps.den;
146
147    return 0;
148}
149
150static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
151{
152    TMVContext *tmv   = s->priv_data;
153    AVIOContext *pb = s->pb;
154    int ret, pkt_size = tmv->stream_index ?
155                        tmv->audio_chunk_size : tmv->video_chunk_size;
156
157    if (url_feof(pb))
158        return AVERROR_EOF;
159
160    ret = av_get_packet(pb, pkt, pkt_size);
161
162    if (tmv->stream_index)
163        avio_skip(pb, tmv->padding);
164
165    pkt->stream_index  = tmv->stream_index;
166    tmv->stream_index ^= 1;
167    pkt->flags        |= AV_PKT_FLAG_KEY;
168
169    return ret;
170}
171
172static int tmv_read_seek(AVFormatContext *s, int stream_index,
173                         int64_t timestamp, int flags)
174{
175    TMVContext *tmv = s->priv_data;
176    int64_t pos;
177
178    if (stream_index)
179        return -1;
180
181    pos = timestamp *
182          (tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
183
184    if (avio_seek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET) < 0)
185        return -1;
186    tmv->stream_index = 0;
187    return 0;
188}
189
190AVInputFormat ff_tmv_demuxer = {
191    .name           = "tmv",
192    .long_name      = NULL_IF_CONFIG_SMALL("8088flex TMV"),
193    .priv_data_size = sizeof(TMVContext),
194    .read_probe     = tmv_probe,
195    .read_header    = tmv_read_header,
196    .read_packet    = tmv_read_packet,
197    .read_seek      = tmv_read_seek,
198    .flags          = AVFMT_GENERIC_INDEX,
199};
200