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