FFmpeg: libavformat/bfi.c Source File

FFmpeg
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 
29 #include "libavutil/channel_layout.h"
30 #include "libavutil/intreadwrite.h"
31 #include "avformat.h"
32 #include "internal.h"
33 
34 typedef struct BFIContext {
35   int nframes;
36   int audio_frame;
37   int video_frame;
38   int video_size;
39   int avflag;
40 } BFIContext;
41 
42  static int bfi_probe(const 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 
51  static int bfi_read_header(AVFormatContext * s)
52 {
53  BFIContext *bfi = s->priv_data;
54  AVIOContext *pb = s->pb;
55  AVStream *vstream;
56  AVStream *astream;
57  int ret, 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  if (chunk_header < 3)
73  return AVERROR_INVALIDDATA;
74 
75  bfi->nframes = avio_rl32(pb);
76  if (bfi->nframes < 0)
77  return AVERROR_INVALIDDATA;
78  avio_rl32(pb);
79  avio_rl32(pb);
80  avio_rl32(pb);
81  fps = avio_rl32(pb);
82  avio_skip(pb, 12);
83  vstream->codecpar->width = avio_rl32(pb);
84  vstream->codecpar->height = avio_rl32(pb);
85 
86  /*Load the palette to extradata */
87  avio_skip(pb, 8);
88  ret = ff_get_extradata(s, vstream->codecpar, pb, 768);
89  if (ret < 0)
90  return ret;
91 
92  astream->codecpar->sample_rate = avio_rl32(pb);
93  if (astream->codecpar->sample_rate <= 0) {
94  av_log(s, AV_LOG_ERROR, "Invalid sample rate %d\n", astream->codecpar->sample_rate);
95  return AVERROR_INVALIDDATA;
96  }
97 
98  /* Set up the video codec... */
99  avpriv_set_pts_info(vstream, 32, 1, fps);
100  vstream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
101  vstream->codecpar->codec_id = AV_CODEC_ID_BFI;
102  vstream->codecpar->format = AV_PIX_FMT_PAL8;
103  vstream->nb_frames =
104  vstream->duration = bfi->nframes;
105 
106  /* Set up the audio codec now... */
107  astream->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
108  astream->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
109  astream->codecpar->channels = 1;
110  astream->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
111  astream->codecpar->bits_per_coded_sample = 8;
112  astream->codecpar->bit_rate =
113  (int64_t)astream->codecpar->sample_rate * astream->codecpar->bits_per_coded_sample;
114  avio_seek(pb, chunk_header - 3, SEEK_SET);
115  avpriv_set_pts_info(astream, 64, 1, astream->codecpar->sample_rate);
116  return 0;
117 }
118 
119 
120  static int bfi_read_packet(AVFormatContext * s, AVPacket * pkt)
121 {
122  BFIContext *bfi = s->priv_data;
123  AVIOContext *pb = s->pb;
124  int ret, audio_offset, video_offset, chunk_size, audio_size = 0;
125  if (bfi->nframes == 0 || avio_feof(pb)) {
126  return AVERROR_EOF;
127  }
128 
129  /* If all previous chunks were completely read, then find a new one... */
130  if (!bfi->avflag) {
131  uint32_t state = 0;
132  while(state != MKTAG('S','A','V','I')){
133  if (avio_feof(pb))
134  return AVERROR(EIO);
135  state = 256*state + avio_r8(pb);
136  }
137  /* Now that the chunk's location is confirmed, we proceed... */
138  chunk_size = avio_rl32(pb);
139  avio_rl32(pb);
140  audio_offset = avio_rl32(pb);
141  avio_rl32(pb);
142  video_offset = avio_rl32(pb);
143  audio_size = video_offset - audio_offset;
144  bfi->video_size = chunk_size - video_offset;
145  if (audio_size < 0 || bfi->video_size < 0) {
146  av_log(s, AV_LOG_ERROR, "Invalid audio/video offsets or chunk size\n");
147  return AVERROR_INVALIDDATA;
148  }
149 
150  //Tossing an audio packet at the audio decoder.
151  ret = av_get_packet(pb, pkt, audio_size);
152  if (ret < 0)
153  return ret;
154 
155  pkt->pts = bfi->audio_frame;
156  bfi->audio_frame += ret;
157  } else if (bfi->video_size > 0) {
158 
159  //Tossing a video packet at the video decoder.
160  ret = av_get_packet(pb, pkt, bfi->video_size);
161  if (ret < 0)
162  return ret;
163 
164  pkt->pts = bfi->video_frame;
165  bfi->video_frame += ret / bfi->video_size;
166 
167  /* One less frame to read. A cursory decrement. */
168  bfi->nframes--;
169  } else {
170  /* Empty video packet */
171  ret = AVERROR(EAGAIN);
172  }
173 
174  bfi->avflag = !bfi->avflag;
175  pkt->stream_index = bfi->avflag;
176  return ret;
177 }
178 
179  const AVInputFormat ff_bfi_demuxer = {
180  .name = "bfi",
181  .long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
182  .priv_data_size = sizeof(BFIContext),
183  .read_probe = bfi_probe,
184  .read_header = bfi_read_header,
185  .read_packet = bfi_read_packet,
186 };
AVERROR
Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
avformat_new_stream
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:768
bfi_probe
static int bfi_probe(const AVProbeData *p)
Definition: bfi.c:42
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
ff_get_extradata
int ff_get_extradata(AVFormatContext *s, AVCodecParameters *par, AVIOContext *pb, int size)
Allocate extradata with additional AV_INPUT_BUFFER_PADDING_SIZE at end which is always set to 0 and f...
Definition: utils.c:469
bfi_read_packet
static int bfi_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: bfi.c:120
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
AV_CH_LAYOUT_MONO
#define AV_CH_LAYOUT_MONO
Definition: channel_layout.h:90
BFIContext::video_size
int video_size
Definition: bfi.c:38
BFIContext::video_frame
int video_frame
Definition: bfi.c:37
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:459
AVCodecParameters::channels
int channels
Audio only.
Definition: codec_par.h:166
AVStream::duration
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:985
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
AVInputFormat
Definition: avformat.h:650
BFIContext
Definition: bfi.c:34
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
AVInputFormat::name
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:655
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:449
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVCodecParameters::width
int width
Video only.
Definition: codec_par.h:126
AVFormatContext
Format I/O context.
Definition: avformat.h:1200
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1095
ff_bfi_demuxer
const AVInputFormat ff_bfi_demuxer
Definition: bfi.c:179
read_header
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:527
NULL
#define NULL
Definition: coverity.c:32
read_probe
static int read_probe(const AVProbeData *pd)
Definition: jvdec.c:55
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:447
AVCodecParameters::sample_rate
int sample_rate
Audio only.
Definition: codec_par.h:170
AVStream::nb_frames
int64_t nb_frames
number of frames in this stream if known or 0
Definition: avformat.h:987
avio_rl32
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:759
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
state
static struct @320 state
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
avio_r8
int avio_r8(AVIOContext *s)
Definition: aviobuf.c:632
AVPacket::pts
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:366
AVCodecParameters::height
int height
Definition: codec_par.h:127
av_get_packet
int av_get_packet(AVIOContext *s, AVPacket *pkt, int size)
Allocate and read the payload of a packet and initialize its fields with default values.
Definition: utils.c:197
AV_PIX_FMT_PAL8
@ AV_PIX_FMT_PAL8
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
ret
ret
Definition: filter_design.txt:187
read_packet
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
AVStream
Stream structure.
Definition: avformat.h:935
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:260
BFIContext::avflag
int avflag
Definition: bfi.c:39
avformat.h
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
bfi_read_header
static int bfi_read_header(AVFormatContext *s)
Definition: bfi.c:51
channel_layout.h
AV_CODEC_ID_BFI
@ AV_CODEC_ID_BFI
Definition: codec_id.h:167
BFIContext::nframes
int nframes
Definition: bfi.c:35
avpriv_set_pts_info
void avpriv_set_pts_info(AVStream *st, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:1196
AVPacket::stream_index
int stream_index
Definition: packet.h:375
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:347
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AVCodecParameters::bits_per_coded_sample
int bits_per_coded_sample
The number of bits per sample in the codedwords.
Definition: codec_par.h:102
AV_CODEC_ID_PCM_U8
@ AV_CODEC_ID_PCM_U8
Definition: codec_id.h:319
AVCodecParameters::format
int format
Definition: codec_par.h:84
AVCodecParameters::codec_id
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVPacket
This structure stores compressed data.
Definition: packet.h:350
AVCodecParameters::channel_layout
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
AVCodecParameters::bit_rate
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: codec_par.h:89
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MKTAG
#define MKTAG(a, b, c, d)
Definition: macros.h:55
BFIContext::audio_frame
int audio_frame
Definition: bfi.c:36
avio_feof
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:375
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