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