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
34 enum {
35 TMV_PADDING = 0x01,
36 TMV_STEREO = 0x02,
37 };
38
39 #define TMV_TAG MKTAG('T', 'M', 'A', 'V')
40
41 typedef 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
tmv_probe(const AVProbeData * p)54 static int tmv_probe(const 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
tmv_read_header(AVFormatContext * s)67 static 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->codecpar->sample_rate = avio_rl16(pb);
85 if (!ast->codecpar->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 if (!tmv->video_chunk_size) {
107 av_log(s, AV_LOG_ERROR, "invalid video chunk size\n");
108 return AVERROR_INVALIDDATA;
109 }
110
111 features = avio_r8(pb);
112 if (features & ~(TMV_PADDING | TMV_STEREO)) {
113 av_log(s, AV_LOG_ERROR, "unsupported features 0x%02x\n",
114 features & ~(TMV_PADDING | TMV_STEREO));
115 return -1;
116 }
117
118 ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
119 ast->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
120 av_channel_layout_default(&ast->codecpar->ch_layout, !!(features & TMV_STEREO) + 1);
121 ast->codecpar->bits_per_coded_sample = 8;
122 ast->codecpar->bit_rate = ast->codecpar->sample_rate *
123 ast->codecpar->bits_per_coded_sample;
124 avpriv_set_pts_info(ast, 32, 1, ast->codecpar->sample_rate);
125
126 fps.num = ast->codecpar->sample_rate * ast->codecpar->ch_layout.nb_channels;
127 fps.den = tmv->audio_chunk_size;
128 av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
129
130 vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
131 vst->codecpar->codec_id = AV_CODEC_ID_TMV;
132 vst->codecpar->format = AV_PIX_FMT_PAL8;
133 vst->codecpar->width = char_cols * 8;
134 vst->codecpar->height = char_rows * 8;
135 avpriv_set_pts_info(vst, 32, fps.den, fps.num);
136
137 if (features & TMV_PADDING)
138 tmv->padding =
139 ((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
140 (tmv->video_chunk_size + tmv->audio_chunk_size);
141
142 vst->codecpar->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
143 fps.num * 8) / fps.den;
144
145 return 0;
146 }
147
tmv_read_packet(AVFormatContext * s,AVPacket * pkt)148 static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
149 {
150 TMVContext *tmv = s->priv_data;
151 AVIOContext *pb = s->pb;
152 int ret, pkt_size = tmv->stream_index ?
153 tmv->audio_chunk_size : tmv->video_chunk_size;
154
155 if (avio_feof(pb))
156 return AVERROR_EOF;
157
158 ret = av_get_packet(pb, pkt, pkt_size);
159
160 if (tmv->stream_index)
161 avio_skip(pb, tmv->padding);
162
163 pkt->stream_index = tmv->stream_index;
164 tmv->stream_index ^= 1;
165 pkt->flags |= AV_PKT_FLAG_KEY;
166
167 return ret;
168 }
169
tmv_read_seek(AVFormatContext * s,int stream_index,int64_t timestamp,int flags)170 static int tmv_read_seek(AVFormatContext *s, int stream_index,
171 int64_t timestamp, int flags)
172 {
173 TMVContext *tmv = s->priv_data;
174 int64_t pos;
175
176 if (stream_index)
177 return -1;
178
179 pos = timestamp *
180 (tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
181
182 if (avio_seek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET) < 0)
183 return -1;
184 tmv->stream_index = 0;
185 return 0;
186 }
187
188 const AVInputFormat ff_tmv_demuxer = {
189 .name = "tmv",
190 .long_name = NULL_IF_CONFIG_SMALL("8088flex TMV"),
191 .priv_data_size = sizeof(TMVContext),
192 .read_probe = tmv_probe,
193 .read_header = tmv_read_header,
194 .read_packet = tmv_read_packet,
195 .read_seek = tmv_read_seek,
196 .flags = AVFMT_GENERIC_INDEX,
197 };
198