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bfi.c
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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
24  * @brief Brute Force & Ignorance (.bfi) file demuxer
25  * @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
26  * @see http://wiki.multimedia.cx/index.php?title=BFI
27  */
28 
30 #include "libavutil/intreadwrite.h"
31 #include "avformat.h"
32 #include "internal.h"
33 
34 typedef struct BFIContext {
35  int nframes;
39  int avflag;
40 } BFIContext;
41 
42 static int bfi_probe(AVProbeData * p)
43 {
44  /* Check file header */
45  if (AV_RL32(p->buf) == MKTAG('B', 'F', '&', 'I'))
46  return AVPROBE_SCORE_MAX;
47  else
48  return 0;
49 }
50 
52 {
53  BFIContext *bfi = s->priv_data;
54  AVIOContext *pb = s->pb;
55  AVStream *vstream;
56  AVStream *astream;
57  int fps, chunk_header;
58 
59  /* Initialize the video codec... */
60  vstream = avformat_new_stream(s, NULL);
61  if (!vstream)
62  return AVERROR(ENOMEM);
63 
64  /* Initialize the audio codec... */
65  astream = avformat_new_stream(s, NULL);
66  if (!astream)
67  return AVERROR(ENOMEM);
68 
69  /* Set the total number of frames. */
70  avio_skip(pb, 8);
71  chunk_header = avio_rl32(pb);
72  bfi->nframes = avio_rl32(pb);
73  avio_rl32(pb);
74  avio_rl32(pb);
75  avio_rl32(pb);
76  fps = avio_rl32(pb);
77  avio_skip(pb, 12);
78  vstream->codec->width = avio_rl32(pb);
79  vstream->codec->height = avio_rl32(pb);
80 
81  /*Load the palette to extradata */
82  avio_skip(pb, 8);
83  vstream->codec->extradata = av_malloc(768);
84  vstream->codec->extradata_size = 768;
85  avio_read(pb, vstream->codec->extradata,
86  vstream->codec->extradata_size);
87 
88  astream->codec->sample_rate = avio_rl32(pb);
89 
90  /* Set up the video codec... */
91  avpriv_set_pts_info(vstream, 32, 1, fps);
93  vstream->codec->codec_id = AV_CODEC_ID_BFI;
94  vstream->codec->pix_fmt = AV_PIX_FMT_PAL8;
95  vstream->nb_frames =
96  vstream->duration = bfi->nframes;
97 
98  /* Set up the audio codec now... */
100  astream->codec->codec_id = AV_CODEC_ID_PCM_U8;
101  astream->codec->channels = 1;
103  astream->codec->bits_per_coded_sample = 8;
104  astream->codec->bit_rate =
105  astream->codec->sample_rate * astream->codec->bits_per_coded_sample;
106  avio_seek(pb, chunk_header - 3, SEEK_SET);
107  avpriv_set_pts_info(astream, 64, 1, astream->codec->sample_rate);
108  return 0;
109 }
110 
111 
113 {
114  BFIContext *bfi = s->priv_data;
115  AVIOContext *pb = s->pb;
116  int ret, audio_offset, video_offset, chunk_size, audio_size = 0;
117  if (bfi->nframes == 0 || url_feof(pb)) {
118  return AVERROR_EOF;
119  }
120 
121  /* If all previous chunks were completely read, then find a new one... */
122  if (!bfi->avflag) {
123  uint32_t state = 0;
124  while(state != MKTAG('S','A','V','I')){
125  if (url_feof(pb))
126  return AVERROR(EIO);
127  state = 256*state + avio_r8(pb);
128  }
129  /* Now that the chunk's location is confirmed, we proceed... */
130  chunk_size = avio_rl32(pb);
131  avio_rl32(pb);
132  audio_offset = avio_rl32(pb);
133  avio_rl32(pb);
134  video_offset = avio_rl32(pb);
135  audio_size = video_offset - audio_offset;
136  bfi->video_size = chunk_size - video_offset;
137 
138  //Tossing an audio packet at the audio decoder.
139  ret = av_get_packet(pb, pkt, audio_size);
140  if (ret < 0)
141  return ret;
142 
143  pkt->pts = bfi->audio_frame;
144  bfi->audio_frame += ret;
145  }
146 
147  else {
148 
149  //Tossing a video packet at the video decoder.
150  ret = av_get_packet(pb, pkt, bfi->video_size);
151  if (ret < 0)
152  return ret;
153 
154  pkt->pts = bfi->video_frame;
155  bfi->video_frame += bfi->video_size ? ret / bfi->video_size : 1;
156 
157  /* One less frame to read. A cursory decrement. */
158  bfi->nframes--;
159  }
160 
161  bfi->avflag = !bfi->avflag;
162  pkt->stream_index = bfi->avflag;
163  return ret;
164 }
165 
167  .name = "bfi",
168  .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
169  .priv_data_size = sizeof(BFIContext),
173 };