FFmpeg: libavformat/smjpegdec.c Source File
Go to the documentation of this file. 1 /*
2 * SMJPEG demuxer
3 * Copyright (c) 2011 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
22 /**
23 * @file
24 * This is a demuxer for Loki SDL Motion JPEG files
25 */
26
27 #include <inttypes.h>
28
34
39
41 {
44 return 0;
45 }
46
48 {
54
57
62
64
70 if (!hlength || hlength > 512)
79 }
83 break;
85 if (ast) {
88 }
90 if (hlength < 8)
93 if (!ast)
106 break;
108 if (vst) {
111 }
113 if (hlength < 12)
116 if (!vst)
122 vst->codecpar->codec_tag =
avio_rl32(pb);
124 vst->codecpar->codec_tag);
129 break;
131 return 0;
132 default:
135 }
136 }
137
139 }
140
142 {
144 uint32_t dtype,
size, timestamp;
147
152 switch (dtype) {
162 break;
172 break;
175 break;
176 default:
179 break;
180 }
182 }
183
187 .p.extensions = "mjpg",
193 };
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
enum AVMediaType codec_type
General type of the encoded data.
AVStream * avformat_new_stream(AVFormatContext *s, const struct AVCodec *c)
Add a new stream to a media file.
#define AVERROR_EOF
End of file.
uint32_t codec_tag
Additional information about the codec (corresponds to the AVI FOURCC).
int nb_channels
Number of channels in this layout.
static int smjpeg_read_packet(AVFormatContext *s, AVPacket *pkt)
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
static int smjpeg_read_header(AVFormatContext *s)
int64_t duration
Decoding: duration of the stream, in stream time base.
#define AV_DICT_DONT_STRDUP_VAL
Take ownership of a value that's been allocated with av_malloc() or another memory allocation functio...
unsigned int avio_rb32(AVIOContext *s)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
unsigned char * buf
Buffer must have AVPROBE_PADDING_SIZE of extra allocated bytes filled with zero.
AVCodecParameters * codecpar
Codec parameters associated with this stream.
static int read_header(FFV1Context *f)
#define AVERROR_PATCHWELCOME
Not yet implemented in FFmpeg, patches welcome.
This structure contains the data a format has to probe a file.
AVChannelLayout ch_layout
Audio only.
const AVCodecTag ff_codec_smjpeg_audio_tags[]
int sample_rate
Audio only.
const AVCodecTag ff_codec_smjpeg_video_tags[]
unsigned int avio_rl32(AVIOContext *s)
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
int avio_r8(AVIOContext *s)
const FFInputFormat ff_smjpeg_demuxer
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
static int FUNC() comment(CodedBitstreamContext *ctx, RWContext *rw, JPEGRawComment *current)
unsigned int avio_rb16(AVIOContext *s)
int index
stream index in AVFormatContext
static int smjpeg_probe(const AVProbeData *p)
int avio_read(AVIOContext *s, unsigned char *buf, int size)
Read size bytes from AVIOContext into buf.
int64_t avio_skip(AVIOContext *s, int64_t offset)
Skip given number of bytes forward.
static int read_probe(const AVProbeData *p)
int bits_per_coded_sample
The number of bits per sample in the codedwords.
#define avpriv_request_sample(...)
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
This structure stores compressed data.
int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags)
Set the given entry in *pm, overwriting an existing entry.
int64_t pos
byte position in stream, -1 if unknown
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
int avio_feof(AVIOContext *s)
Similar to feof() but also returns nonzero on read errors.
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