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  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(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->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.  
  150. static 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.  
  172. static 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.  
  190. AVInputFormat 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.