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 libavformat/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 "libavutil/intreadwrite.h"
  30 #include "avformat.h"
  31
  32 typedef struct BFIContext {
  33     int nframes;
  34     int audio_frame;
  35     int video_frame;
  36     int video_size;
  37     int avflag;
  38 } BFIContext;
  39
  40 static int bfi_probe(AVProbeData * p)
  41 {
  42     /* Check file header */
  43     if (AV_RL32(p->buf) == MKTAG('B', 'F', '&', 'I'))
  44         return AVPROBE_SCORE_MAX;
  45     else
  46         return 0;
  47 }
  48
  49 static int bfi_read_header(AVFormatContext * s, AVFormatParameters * ap)
  50 {
  51     BFIContext *bfi = s->priv_data;
  52     ByteIOContext *pb = s->pb;
  53     AVStream *vstream;
  54     AVStream *astream;
  55     int fps, chunk_header;
  56
  57     /* Initialize the video codec... */
  58     vstream = av_new_stream(s, 0);
  59     if (!vstream)
  60         return AVERROR(ENOMEM);
  61
  62     /* Initialize the audio codec... */
  63     astream = av_new_stream(s, 0);
  64     if (!astream)
  65         return AVERROR(ENOMEM);
  66
  67     /* Set the total number of frames. */
  68     url_fskip(pb, 8);
  69     chunk_header           = get_le32(pb);
  70     bfi->nframes           = get_le32(pb);
  71     get_le32(pb);
  72     get_le32(pb);
  73     get_le32(pb);
  74     fps                    = get_le32(pb);
  75     url_fskip(pb, 12);
  76     vstream->codec->width  = get_le32(pb);
  77     vstream->codec->height = get_le32(pb);
  78
  79     /*Load the palette to extradata */
  80     url_fskip(pb, 8);
  81     vstream->codec->extradata      = av_malloc(768);
  82     vstream->codec->extradata_size = 768;
  83     get_buffer(pb, vstream->codec->extradata,
  84                vstream->codec->extradata_size);
  85
  86     astream->codec->sample_rate = get_le32(pb);
  87
  88     /* Set up the video codec... */
  89     av_set_pts_info(vstream, 32, 1, fps);
  90     vstream->codec->codec_type = CODEC_TYPE_VIDEO;
  91     vstream->codec->codec_id   = CODEC_ID_BFI;
  92     vstream->codec->pix_fmt    = PIX_FMT_PAL8;
  93
  94     /* Set up the audio codec now... */
  95     astream->codec->codec_type      = CODEC_TYPE_AUDIO;
  96     astream->codec->codec_id        = CODEC_ID_PCM_U8;
  97     astream->codec->channels        = 1;
  98     astream->codec->bits_per_coded_sample = 8;
  99     astream->codec->bit_rate        =
 100         astream->codec->sample_rate * astream->codec->bits_per_coded_sample;
 101     url_fseek(pb, chunk_header - 3, SEEK_SET);
 102     av_set_pts_info(astream, 64, 1, astream->codec->sample_rate);
 103     return 0;
 104 }
 105
 106
 107 static int bfi_read_packet(AVFormatContext * s, AVPacket * pkt)
 108 {
 109     BFIContext *bfi = s->priv_data;
 110     ByteIOContext *pb = s->pb;
 111     int ret, audio_offset, video_offset, chunk_size, audio_size = 0;
 112     if (bfi->nframes == 0 || url_feof(pb)) {
 113         return AVERROR(EIO);
 114     }
 115
 116     /* If all previous chunks were completely read, then find a new one... */
 117     if (!bfi->avflag) {
 118         uint32_t state = 0;
 119         while(state != MKTAG('S','A','V','I')){
 120             if (url_feof(pb))
 121                 return AVERROR(EIO);
 122             state = 256*state + get_byte(pb);
 123         }
 124         /* Now that the chunk's location is confirmed, we proceed... */
 125         chunk_size      = get_le32(pb);
 126         get_le32(pb);
 127         audio_offset    = get_le32(pb);
 128         get_le32(pb);
 129         video_offset    = get_le32(pb);
 130         audio_size      = video_offset - audio_offset;
 131         bfi->video_size = chunk_size - video_offset;
 132
 133         //Tossing an audio packet at the audio decoder.
 134         ret = av_get_packet(pb, pkt, audio_size);
 135         if (ret < 0)
 136             return ret;
 137
 138         pkt->pts          = bfi->audio_frame;
 139         bfi->audio_frame += ret;
 140     }
 141
 142     else {
 143
 144         //Tossing a video packet at the video decoder.
 145         ret = av_get_packet(pb, pkt, bfi->video_size);
 146         if (ret < 0)
 147             return ret;
 148
 149         pkt->pts          = bfi->video_frame;
 150         bfi->video_frame += ret / bfi->video_size;
 151
 152         /* One less frame to read. A cursory decrement. */
 153         bfi->nframes--;
 154     }
 155
 156     bfi->avflag       = !bfi->avflag;
 157     pkt->stream_index = bfi->avflag;
 158     return ret;
 159 }
 160
 161 AVInputFormat bfi_demuxer = {
 162     "bfi",
 163     NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
 164     sizeof(BFIContext),
 165     bfi_probe,
 166     bfi_read_header,
 167     bfi_read_packet,
 168 };