/*
  * 8088flex TMV file demuxer
  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * 8088flex TMV file demuxer

  * @author Daniel Verkamp

  * @see http://www.oldskool.org/pc/8088_Corruption

  */
 

 #include "libavutil/channel_layout.h"

 #include "libavutil/intreadwrite.h"
 #include "avformat.h"

 #include "internal.h"

 
 enum {
     TMV_PADDING = 0x01,
     TMV_STEREO  = 0x02,
 };
 
 #define TMV_TAG MKTAG('T', 'M', 'A', 'V')
 
 typedef struct TMVContext {
     unsigned audio_chunk_size;
     unsigned video_chunk_size;
     unsigned padding;
     unsigned stream_index;
 } TMVContext;
 

 #define TMV_HEADER_SIZE       12
 

 #define PROBE_MIN_SAMPLE_RATE 5000
 #define PROBE_MAX_FPS         120
 #define PROBE_MIN_AUDIO_SIZE  (PROBE_MIN_SAMPLE_RATE / PROBE_MAX_FPS)
 

 static int tmv_probe(AVProbeData *p)
 {

     if (AV_RL32(p->buf)   == TMV_TAG &&
         AV_RL16(p->buf+4) >= PROBE_MIN_SAMPLE_RATE &&
         AV_RL16(p->buf+6) >= PROBE_MIN_AUDIO_SIZE  &&
                !p->buf[8] && // compression method
                 p->buf[9] && // char cols
                 p->buf[10])  // char rows

         return AVPROBE_SCORE_MAX /
             ((p->buf[9] == 40 && p->buf[10] == 25) ? 1 : 4);

     return 0;
 }
 

 static int tmv_read_header(AVFormatContext *s)

 {
     TMVContext *tmv   = s->priv_data;

     AVIOContext *pb = s->pb;

     AVStream *vst, *ast;
     AVRational fps;
     unsigned comp_method, char_cols, char_rows, features;
 

     if (avio_rl32(pb) != TMV_TAG)

         return -1;
 

     if (!(vst = avformat_new_stream(s, NULL)))

         return AVERROR(ENOMEM);
 

     if (!(ast = avformat_new_stream(s, NULL)))

         return AVERROR(ENOMEM);
 

     ast->codec->sample_rate = avio_rl16(pb);

     if (!ast->codec->sample_rate) {
         av_log(s, AV_LOG_ERROR, "invalid sample rate\n");
         return -1;
     }
 

     tmv->audio_chunk_size   = avio_rl16(pb);

     if (!tmv->audio_chunk_size) {
         av_log(s, AV_LOG_ERROR, "invalid audio chunk size\n");
         return -1;
     }
 

     comp_method             = avio_r8(pb);

     if (comp_method) {
         av_log(s, AV_LOG_ERROR, "unsupported compression method %d\n",
                comp_method);
         return -1;
     }
 

     char_cols = avio_r8(pb);
     char_rows = avio_r8(pb);

     tmv->video_chunk_size = char_cols * char_rows * 2;
 

     features  = avio_r8(pb);

     if (features & ~(TMV_PADDING | TMV_STEREO)) {
         av_log(s, AV_LOG_ERROR, "unsupported features 0x%02x\n",
                features & ~(TMV_PADDING | TMV_STEREO));
         return -1;
     }
 

     ast->codec->codec_type            = AVMEDIA_TYPE_AUDIO;

     ast->codec->codec_id              = AV_CODEC_ID_PCM_U8;

     if (features & TMV_STEREO) {
         ast->codec->channels       = 2;
         ast->codec->channel_layout = AV_CH_LAYOUT_STEREO;
     } else {
         ast->codec->channels       = 1;
         ast->codec->channel_layout = AV_CH_LAYOUT_MONO;
     }

     ast->codec->bits_per_coded_sample = 8;
     ast->codec->bit_rate              = ast->codec->sample_rate *
                                         ast->codec->bits_per_coded_sample;

     avpriv_set_pts_info(ast, 32, 1, ast->codec->sample_rate);

 
     fps.num = ast->codec->sample_rate * ast->codec->channels;
     fps.den = tmv->audio_chunk_size;
     av_reduce(&fps.num, &fps.den, fps.num, fps.den, 0xFFFFFFFFLL);
 

     vst->codec->codec_type = AVMEDIA_TYPE_VIDEO;

     vst->codec->codec_id   = AV_CODEC_ID_TMV;

     vst->codec->pix_fmt    = AV_PIX_FMT_PAL8;

     vst->codec->width      = char_cols * 8;
     vst->codec->height     = char_rows * 8;

     avpriv_set_pts_info(vst, 32, fps.den, fps.num);

 
     if (features & TMV_PADDING)
         tmv->padding =
             ((tmv->video_chunk_size + tmv->audio_chunk_size + 511) & ~511) -
              (tmv->video_chunk_size + tmv->audio_chunk_size);
 
     vst->codec->bit_rate = ((tmv->video_chunk_size + tmv->padding) *
                             fps.num * 8) / fps.den;
 
     return 0;
 }
 
 static int tmv_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     TMVContext *tmv   = s->priv_data;

     AVIOContext *pb = s->pb;

     int ret, pkt_size = tmv->stream_index ?
                         tmv->audio_chunk_size : tmv->video_chunk_size;
 
     if (url_feof(pb))
         return AVERROR_EOF;
 
     ret = av_get_packet(pb, pkt, pkt_size);
 
     if (tmv->stream_index)

         avio_skip(pb, tmv->padding);

 
     pkt->stream_index  = tmv->stream_index;
     tmv->stream_index ^= 1;

     pkt->flags        |= AV_PKT_FLAG_KEY;

 
     return ret;
 }
 

 static int tmv_read_seek(AVFormatContext *s, int stream_index,
                          int64_t timestamp, int flags)
 {
     TMVContext *tmv = s->priv_data;
     int64_t pos;
 
     if (stream_index)
         return -1;
 
     pos = timestamp *
           (tmv->audio_chunk_size + tmv->video_chunk_size + tmv->padding);
 

     if (avio_seek(s->pb, pos + TMV_HEADER_SIZE, SEEK_SET) < 0)
         return -1;

     tmv->stream_index = 0;
     return 0;
 }
 

 AVInputFormat ff_tmv_demuxer = {

     .name           = "tmv",
     .long_name      = NULL_IF_CONFIG_SMALL("8088flex TMV"),
     .priv_data_size = sizeof(TMVContext),
     .read_probe     = tmv_probe,
     .read_header    = tmv_read_header,
     .read_packet    = tmv_read_packet,
     .read_seek      = tmv_read_seek,

     .flags          = AVFMT_GENERIC_INDEX,

 };