FFmpeg
vocdec.c
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1 /*
2  * Creative Voice File demuxer.
3  * Copyright (c) 2006 Aurelien Jacobs <aurel@gnuage.org>
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 #include "libavutil/intreadwrite.h"
23 #include "voc.h"
24 #include "internal.h"
25 
26 static int voc_probe(const AVProbeData *p)
27 {
28  int version, check;
29 
30  if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))
31  return 0;
32  version = AV_RL16(p->buf + 22);
33  check = AV_RL16(p->buf + 24);
34  if (~version + 0x1234 != check)
35  return 10;
36 
37  return AVPROBE_SCORE_MAX;
38 }
39 
41 {
42  VocDecContext *voc = s->priv_data;
43  AVIOContext *pb = s->pb;
44  int header_size;
45 
46  avio_skip(pb, 20);
47  header_size = avio_rl16(pb) - 22;
48  if (header_size != 4) {
49  av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);
50  return AVERROR(ENOSYS);
51  }
52  avio_skip(pb, header_size);
53 
54  s->ctx_flags |= AVFMTCTX_NOHEADER;
55 
56  voc->remaining_size = 0;
57  return 0;
58 }
59 
61 {
62  if (!s->nb_streams) {
64  if (!st)
65  return AVERROR(ENOMEM);
67  }
68  return ff_voc_get_packet(s, pkt, s->streams[0], 0);
69 }
70 
71 static int voc_read_seek(AVFormatContext *s, int stream_index,
72  int64_t timestamp, int flags)
73 {
74  VocDecContext *voc = s->priv_data;
75  AVStream *st;
76  int index;
77 
78  if (s->nb_streams < 1) {
79  av_log(s, AV_LOG_ERROR, "cannot seek while no stream was found yet\n");
80  return AVERROR(EINVAL);
81  }
82 
83  st = s->streams[stream_index];
84  index = av_index_search_timestamp(st, timestamp, flags);
85 
86  if (index >= 0 && index < st->internal->nb_index_entries - 1) {
88  avio_seek(s->pb, e->pos, SEEK_SET);
89  voc->pts = e->timestamp;
90  voc->remaining_size = e->size;
91  return 0;
92  } else if (st->internal->nb_index_entries && st->internal->index_entries[0].timestamp <= timestamp) {
94  // prepare context for seek_frame_generic()
95  voc->pts = e->timestamp;
96  voc->remaining_size = e->size;
97  }
98  return -1;
99 }
100 
102  .name = "voc",
103  .long_name = NULL_IF_CONFIG_SMALL("Creative Voice"),
104  .priv_data_size = sizeof(VocDecContext),
109  .codec_tag = ff_voc_codec_tags_list,
110 };
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:4372
AVCodecParameters::codec_type
enum AVMediaType codec_type
General type of the encoded data.
Definition: codec_par.h:56
index
fg index
Definition: ffmpeg_filter.c:168
AVStream::internal
AVStreamInternal * internal
An opaque field for libavformat internal usage.
Definition: avformat.h:1008
AVIndexEntry
Definition: avformat.h:762
AVPROBE_SCORE_MAX
#define AVPROBE_SCORE_MAX
maximum score
Definition: avformat.h:453
read_seek
static int read_seek(AVFormatContext *ctx, int stream_index, int64_t timestamp, int flags)
Definition: libcdio.c:153
avio_rl16
unsigned int avio_rl16(AVIOContext *s)
Definition: aviobuf.c:717
voc_read_header
static int voc_read_header(AVFormatContext *s)
Definition: vocdec.c:40
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:181
AVInputFormat
Definition: avformat.h:616
ff_voc_magic
const unsigned char ff_voc_magic[21]
ff_voc_demuxer
const AVInputFormat ff_voc_demuxer
Definition: vocdec.c:101
check
#define check(x, y, S, v)
Definition: motion_est_template.c:405
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:621
AVProbeData::buf
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
Definition: avformat.h:443
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AVIndexEntry::size
int size
Definition: avformat.h:773
AVIndexEntry::timestamp
int64_t timestamp
Timestamp in AVStream.time_base units, preferably the time from which on correctly decoded frames are...
Definition: avformat.h:764
AV_RL16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_RL16
Definition: bytestream.h:94
AVFormatContext
Format I/O context.
Definition: avformat.h:1106
ff_voc_codec_tags_list
const AVCodecTag *const ff_voc_codec_tags_list[]
internal.h
AVStream::codecpar
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:979
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
AVFMTCTX_NOHEADER
#define AVFMTCTX_NOHEADER
signal that no header is present (streams are added dynamically)
Definition: avformat.h:1055
AVProbeData
This structure contains the data a format has to probe a file.
Definition: avformat.h:441
AVIOContext
Bytestream IO Context.
Definition: avio.h:161
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
AVStreamInternal::nb_index_entries
int nb_index_entries
Definition: internal.h:252
AVStreamInternal::index_entries
AVIndexEntry * index_entries
Only used if the format does not support seeking natively.
Definition: internal.h:250
version
version
Definition: libkvazaar.c:306
voc_read_seek
static int voc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
Definition: vocdec.c:71
voc.h
ff_voc_get_packet
int ff_voc_get_packet(AVFormatContext *s, AVPacket *pkt, AVStream *st, int max_size)
Definition: voc_packet.c:27
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:832
avio_seek
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:243
AVIndexEntry::pos
int64_t pos
Definition: avformat.h:763
avio_skip
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
Definition: aviobuf.c:327
voc_read_packet
static int voc_read_packet(AVFormatContext *s, AVPacket *pkt)
Definition: vocdec.c:60
AVPacket
This structure stores compressed data.
Definition: packet.h:342
voc_probe
static int voc_probe(const AVProbeData *p)
Definition: vocdec.c:26
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:28
av_index_search_timestamp
int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags)
Get the index for a specific timestamp.
Definition: utils.c:2054