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(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 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->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 148static 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 170static 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 188const 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