FFmpeg
svs.c
Go to the documentation of this file.
1 /*
2  * SVS demuxer
3  * Copyright (c) 2020 Paul B Mahol
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 
23 #include "libavutil/intreadwrite.h"
24 #include "avformat.h"
25 #include "internal.h"
26 
27 static int svs_probe(const AVProbeData *p)
28 {
29  if (p->buf_size < 32)
30  return 0;
31 
32  if (memcmp(p->buf, "SVS\00", 4))
33  return 0;
34 
35  if (AV_RL32(p->buf + 16) == 0)
36  return 0;
37 
38  return AVPROBE_SCORE_MAX / 3;
39 }
40 
42 {
43  AVStream *st;
44  uint32_t pitch;
45 
46  st = avformat_new_stream(s, NULL);
47  if (!st)
48  return AVERROR(ENOMEM);
49 
50  avio_skip(s->pb, 16);
51  pitch = avio_rl32(s->pb);
52  avio_skip(s->pb, 12);
53 
54  s->internal->data_offset = avio_tell(s->pb);
58  st->codecpar->channels = 2;
59  st->codecpar->sample_rate = av_rescale_rnd(pitch, 48000, 4096, AV_ROUND_INF);
60  st->codecpar->block_align = 32;
61  st->start_time = 0;
64  avio_size(s->pb) - 32);
65 
66  avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
67 
68  return 0;
69 }
70 
72 {
73  int ret;
74 
75  if (avio_feof(s->pb))
76  return AVERROR_EOF;
77 
78  ret = av_get_packet(s->pb, pkt, 32 * 256);
79  if (ret != 32 * 256) {
80  if (ret < 0)
81  return ret;
82  av_shrink_packet(pkt, ret);
83  pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
84  }
85  pkt->stream_index = 0;
86 
87  return ret;
88 }
89 
91  .name = "svs",
92  .long_name = NULL_IF_CONFIG_SMALL("Square SVS"),
93  .read_probe = svs_probe,
94  .read_header = svs_read_header,
95  .read_packet = svs_read_packet,
96  .extensions = "svs",
97 };
#define NULL
Definition: coverity.c:32
int64_t avio_size(AVIOContext *s)
Get the filesize.
Definition: aviobuf.c:346
AVInputFormat ff_svs_demuxer
Definition: svs.c:90
void av_shrink_packet(AVPacket *pkt, int size)
Reduce packet size, correctly zeroing padding.
Definition: avpacket.c:103
void avpriv_set_pts_info(AVStream *s, 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:4868
int64_t data_offset
offset of the first packet
Definition: internal.h:80
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
AVFormatInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1808
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:341
static AVPacket pkt
#define AV_CH_LAYOUT_STEREO
static int svs_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: svs.c:71
Format I/O context.
Definition: avformat.h:1355
static int svs_probe(const AVProbeData *p)
Definition: svs.c:27
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4449
#define AVERROR_EOF
End of file.
Definition: error.h:55
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:305
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
uint64_t channel_layout
Audio only.
Definition: codec_par.h:162
unsigned int avio_rl32(AVIOContext *s)
Definition: aviobuf.c:752
Round away from zero.
Definition: mathematics.h:81
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:153
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
int av_get_audio_frame_duration2(AVCodecParameters *par, int frame_bytes)
This function is the same as av_get_audio_frame_duration(), except it works with AVCodecParameters in...
Definition: utils.c:1792
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:369
int buf_size
Size of buf except extra allocated bytes.
Definition: avformat.h:444
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
int block_align
Audio only.
Definition: codec_par.h:177
int seekable
A combination of AVIO_SEEKABLE_ flags or 0 when the stream is not seekable.
Definition: avio.h:260
audio channel layout utility functions
static int svs_read_header(AVFormatContext *s)
Definition: svs.c:41
#define s(width, name)
Definition: cbs_vp9.c:257
int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding rnd)
Rescale a 64-bit integer with specified rounding.
Definition: mathematics.c:58
Stream structure.
Definition: avformat.h:880
#define AVIO_SEEKABLE_NORMAL
Seeking works like for a local file.
Definition: avio.h:40
AVIOContext * pb
I/O context.
Definition: avformat.h:1397
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
int64_t duration
Decoding: duration of the stream, in stream time base.
Definition: avformat.h:929
int sample_rate
Audio only.
Definition: codec_par.h:170
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
Main libavformat public API header.
int64_t start_time
Decoding: pts of the first frame of the stream in presentation order, in stream time base...
Definition: avformat.h:919
#define AV_PKT_FLAG_CORRUPT
The packet content is corrupted.
Definition: packet.h:402
int channels
Audio only.
Definition: codec_par.h:166
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:652
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1027
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
Definition: aviobuf.c:368
int stream_index
Definition: packet.h:365
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
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:91
This structure stores compressed data.
Definition: packet.h:340