FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
bfi.c
Go to the documentation of this file.
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  if (!vstream->codec->extradata)
85  return AVERROR(ENOMEM);
86  vstream->codec->extradata_size = 768;
87  avio_read(pb, vstream->codec->extradata,
88  vstream->codec->extradata_size);
89 
90  astream->codec->sample_rate = avio_rl32(pb);
91 
92  /* Set up the video codec... */
93  avpriv_set_pts_info(vstream, 32, 1, fps);
95  vstream->codec->codec_id = AV_CODEC_ID_BFI;
96  vstream->codec->pix_fmt = AV_PIX_FMT_PAL8;
97  vstream->nb_frames =
98  vstream->duration = bfi->nframes;
99 
100  /* Set up the audio codec now... */
101  astream->codec->codec_type = AVMEDIA_TYPE_AUDIO;
102  astream->codec->codec_id = AV_CODEC_ID_PCM_U8;
103  astream->codec->channels = 1;
105  astream->codec->bits_per_coded_sample = 8;
106  astream->codec->bit_rate =
107  astream->codec->sample_rate * astream->codec->bits_per_coded_sample;
108  avio_seek(pb, chunk_header - 3, SEEK_SET);
109  avpriv_set_pts_info(astream, 64, 1, astream->codec->sample_rate);
110  return 0;
111 }
112 
113 
115 {
116  BFIContext *bfi = s->priv_data;
117  AVIOContext *pb = s->pb;
118  int ret, audio_offset, video_offset, chunk_size, audio_size = 0;
119  if (bfi->nframes == 0 || url_feof(pb)) {
120  return AVERROR_EOF;
121  }
122 
123  /* If all previous chunks were completely read, then find a new one... */
124  if (!bfi->avflag) {
125  uint32_t state = 0;
126  while(state != MKTAG('S','A','V','I')){
127  if (url_feof(pb))
128  return AVERROR(EIO);
129  state = 256*state + avio_r8(pb);
130  }
131  /* Now that the chunk's location is confirmed, we proceed... */
132  chunk_size = avio_rl32(pb);
133  avio_rl32(pb);
134  audio_offset = avio_rl32(pb);
135  avio_rl32(pb);
136  video_offset = avio_rl32(pb);
137  audio_size = video_offset - audio_offset;
138  bfi->video_size = chunk_size - video_offset;
139  if (audio_size < 0 || bfi->video_size < 0) {
140  av_log(s, AV_LOG_ERROR, "Invalid audio/video offsets or chunk size\n");
141  return AVERROR_INVALIDDATA;
142  }
143 
144  //Tossing an audio packet at the audio decoder.
145  ret = av_get_packet(pb, pkt, audio_size);
146  if (ret < 0)
147  return ret;
148 
149  pkt->pts = bfi->audio_frame;
150  bfi->audio_frame += ret;
151  } else if (bfi->video_size > 0) {
152 
153  //Tossing a video packet at the video decoder.
154  ret = av_get_packet(pb, pkt, bfi->video_size);
155  if (ret < 0)
156  return ret;
157 
158  pkt->pts = bfi->video_frame;
159  bfi->video_frame += ret / bfi->video_size;
160 
161  /* One less frame to read. A cursory decrement. */
162  bfi->nframes--;
163  } else {
164  /* Empty video packet */
165  ret = AVERROR(EAGAIN);
166  }
167 
168  bfi->avflag = !bfi->avflag;
169  pkt->stream_index = bfi->avflag;
170  return ret;
171 }
172 
174  .name = "bfi",
175  .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
176  .priv_data_size = sizeof(BFIContext),
180 };