libavformat/bfi.c

   1 /*
   2  * Brute Force & Ignorance (BFI) demuxer
   3  * Copyright (c) 2008 Sisir Koppaka
   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 bfi.c
  24  * @brief Brute Force & Ignorance (.bfi) file demuxer
  25  * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
  26  * @sa http://wiki.multimedia.cx/index.php?title=BFI
  27  */
  28
  29 #include "avformat.h"
  30
  31 typedef struct BFIContext {
  32     int nframes;
  33     int audio_frame;
  34     int video_frame;
  35     int video_size;
  36     int avflag;
  37 } BFIContext;
  38
  39 static int bfi_probe(AVProbeData * p)
  40 {
  41     /* Check file header */
  42     if (AV_RL32(p->buf) == MKTAG('B', 'F', '&', 'I'))
  43         return AVPROBE_SCORE_MAX;
  44     else
  45         return 0;
  46 }
  47
  48 static int bfi_read_header(AVFormatContext * s, AVFormatParameters * ap)
  49 {
  50     BFIContext *bfi = s->priv_data;
  51     ByteIOContext *pb = s->pb;
  52     AVStream *vstream;
  53     AVStream *astream;
  54     int fps, chunk_header;
  55
  56     /* Initialize the video codec... */
  57     vstream = av_new_stream(s, 0);
  58     if (!vstream)
  59         return AVERROR(ENOMEM);
  60
  61     /* Initialize the audio codec... */
  62     astream = av_new_stream(s, 0);
  63     if (!astream)
  64         return AVERROR(ENOMEM);
  65
  66     /* Set the total number of frames. */
  67     url_fskip(pb, 8);
  68     chunk_header           = get_le32(pb);
  69     bfi->nframes           = get_le32(pb);
  70     get_le32(pb);
  71     get_le32(pb);
  72     get_le32(pb);
  73     fps                    = get_le32(pb);
  74     url_fskip(pb, 12);
  75     vstream->codec->width  = get_le32(pb);
  76     vstream->codec->height = get_le32(pb);
  77
  78     /*Load the palette to extradata */
  79     url_fskip(pb, 8);
  80     vstream->codec->extradata      = av_malloc(768);
  81     vstream->codec->extradata_size = 768;
  82     get_buffer(pb, vstream->codec->extradata,
  83                vstream->codec->extradata_size);
  84
  85     astream->codec->sample_rate = get_le32(pb);
  86
  87     /* Set up the video codec... */
  88     av_set_pts_info(vstream, 32, 1, fps);
  89     vstream->codec->codec_type = CODEC_TYPE_VIDEO;
  90     vstream->codec->codec_id   = CODEC_ID_BFI;
  91     vstream->codec->pix_fmt    = PIX_FMT_PAL8;
  92
  93     /* Set up the audio codec now... */
  94     astream->codec->codec_type      = CODEC_TYPE_AUDIO;
  95     astream->codec->codec_id        = CODEC_ID_PCM_U8;
  96     astream->codec->channels        = 1;
  97     astream->codec->bits_per_coded_sample = 8;
  98     astream->codec->bit_rate        =
  99         astream->codec->sample_rate * astream->codec->bits_per_coded_sample;
 100     url_fseek(pb, chunk_header - 3, SEEK_SET);
 101     av_set_pts_info(astream, 64, 1, astream->codec->sample_rate);
 102     return 0;
 103 }
 104
 105
 106 static int bfi_read_packet(AVFormatContext * s, AVPacket * pkt)
 107 {
 108     BFIContext *bfi = s->priv_data;
 109     ByteIOContext *pb = s->pb;
 110     int ret, audio_offset, video_offset, chunk_size, audio_size = 0;
 111     if (bfi->nframes == 0 || url_feof(pb)) {
 112         return AVERROR(EIO);
 113     }
 114
 115     /* If all previous chunks were completely read, then find a new one... */
 116     if (!bfi->avflag) {
 117         uint32_t state = 0;
 118         while(state != MKTAG('S','A','V','I')){
 119             if (url_feof(pb))
 120                 return AVERROR(EIO);
 121             state = 256*state + get_byte(pb);
 122         }
 123         /* Now that the chunk's location is confirmed, we proceed... */
 124         chunk_size      = get_le32(pb);
 125         get_le32(pb);
 126         audio_offset    = get_le32(pb);
 127         get_le32(pb);
 128         video_offset    = get_le32(pb);
 129         audio_size      = video_offset - audio_offset;
 130         bfi->video_size = chunk_size - video_offset;
 131
 132         //Tossing an audio packet at the audio decoder.
 133         ret = av_get_packet(pb, pkt, audio_size);
 134         if (ret < 0)
 135             return ret;
 136
 137         pkt->pts          = bfi->audio_frame;
 138         bfi->audio_frame += ret;
 139     }
 140
 141     else {
 142
 143         //Tossing a video packet at the video decoder.
 144         ret = av_get_packet(pb, pkt, bfi->video_size);
 145         if (ret < 0)
 146             return ret;
 147
 148         pkt->pts          = bfi->video_frame;
 149         bfi->video_frame += ret / bfi->video_size;
 150
 151         /* One less frame to read. A cursory decrement. */
 152         bfi->nframes--;
 153     }
 154
 155     bfi->avflag       = !bfi->avflag;
 156     pkt->stream_index = bfi->avflag;
 157     return ret;
 158 }
 159
 160 AVInputFormat bfi_demuxer = {
 161     "bfi",
 162     NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
 163     sizeof(BFIContext),
 164     bfi_probe,
 165     bfi_read_header,
 166     bfi_read_packet,
 167 };