libavformat/tmv.c

   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
  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
  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     if (features & TMV_STEREO) {
 121         ast->codecpar->channels       = 2;
 122         ast->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
 123     } else {
 124         ast->codecpar->channels       = 1;
 125         ast->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
 126     }
 127     ast->codecpar->bits_per_coded_sample = 8;
 128     ast->codecpar->bit_rate              = ast->codecpar->sample_rate *
 129                                            ast->codecpar->bits_per_coded_sample;
 130     avpriv_set_pts_info(ast, 32, 1, ast->codecpar->sample_rate);
 131
 132     fps.num = ast->codecpar->sample_rate * ast->codecpar->channels;
 133     fps.den = tmv->audio_chunk_size;
 134     av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
 135
 136     vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 137     vst->codecpar->codec_id   = AV_CODEC_ID_TMV;
 138     vst->codecpar->format     = AV_PIX_FMT_PAL8;
 139     vst->codecpar->width      = char_cols * 8;
 140     vst->codecpar->height     = char_rows * 8;
 141     avpriv_set_pts_info(vst, 32, fps.den, fps.num);
 142
 143     if (features & TMV_PADDING)
 144         tmv->padding =
 145             ((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
 146              (tmv->video_chunk_size + tmv->audio_chunk_size);
 147
 148     vst->codecpar->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
 149                                fps.num * 8) / fps.den;
 150
 151     return 0;
 152 }
 153
 154 static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
 155 {
 156     TMVContext *tmv   = s->priv_data;
 157     AVIOContext *pb = s->pb;
 158     int ret, pkt_size = tmv->stream_index ?
 159                         tmv->audio_chunk_size : tmv->video_chunk_size;
 160
 161     if (avio_feof(pb))
 162         return AVERROR_EOF;
 163
 164     ret = av_get_packet(pb, pkt, pkt_size);
 165
 166     if (tmv->stream_index)
 167         avio_skip(pb, tmv->padding);
 168
 169     pkt->stream_index  = tmv->stream_index;
 170     tmv->stream_index ^= 1;
 171     pkt->flags        |= AV_PKT_FLAG_KEY;
 172
 173     return ret;
 174 }
 175
 176 static int tmv_read_seek(AVFormatContext *s, int stream_index,
 177                          int64_t timestamp, int flags)
 178 {
 179     TMVContext *tmv = s->priv_data;
 180     int64_t pos;
 181
 182     if (stream_index)
 183         return -1;
 184
 185     pos = timestamp *
 186           (tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
 187
 188     if (avio_seek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET) < 0)
 189         return -1;
 190     tmv->stream_index = 0;
 191     return 0;
 192 }
 193
 194 AVInputFormat ff_tmv_demuxer = {
 195     .name           = "tmv",
 196     .long_name      = NULL_IF_CONFIG_SMALL("8088flex TMV"),
 197     .priv_data_size = sizeof(TMVContext),
 198     .read_probe     = tmv_probe,
 199     .read_header    = tmv_read_header,
 200     .read_packet    = tmv_read_packet,
 201     .read_seek      = tmv_read_seek,
 202     .flags          = AVFMT_GENERIC_INDEX,
 203 };