FFmpeg
options.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2001 Fabrice Bellard
3  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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  * Options definition for AVCodecContext.
25  */
26 
27 #include "config_components.h"
28 
29 #include "avcodec.h"
30 #include "codec_internal.h"
31 #include "libavutil/avassert.h"
32 #include "libavutil/internal.h"
33 #include "libavutil/mem.h"
34 #include "libavutil/opt.h"
35 #include <string.h>
36 
38 #include "options_table.h"
40 
41 static const char* context_to_name(void* ptr) {
42  AVCodecContext *avc= ptr;
43 
44  if (avc && avc->codec)
45  return avc->codec->name;
46  else
47  return "NULL";
48 }
49 
50 static void *codec_child_next(void *obj, void *prev)
51 {
52  AVCodecContext *s = obj;
53  if (!prev && s->codec && s->codec->priv_class && s->priv_data)
54  return s->priv_data;
55  return NULL;
56 }
57 
58 static const AVClass *codec_child_class_iterate(void **iter)
59 {
60  const AVCodec *c;
61  /* find next codec with priv options */
62  while (c = av_codec_iterate(iter))
63  if (c->priv_class)
64  return c->priv_class;
65  return NULL;
66 }
67 
68 static AVClassCategory get_category(void *ptr)
69 {
70  AVCodecContext* avctx = ptr;
71  if (avctx->codec && av_codec_is_decoder(avctx->codec))
73  else
75 }
76 
78  .class_name = "AVCodecContext",
79  .item_name = context_to_name,
80  .option = avcodec_options,
81  .version = LIBAVUTIL_VERSION_INT,
82  .log_level_offset_offset = offsetof(AVCodecContext, log_level_offset),
83  .child_next = codec_child_next,
84  .child_class_iterate = codec_child_class_iterate,
86  .get_category = get_category,
87 };
88 
89 static int init_context_defaults(AVCodecContext *s, const AVCodec *codec)
90 {
91  const FFCodec *const codec2 = ffcodec(codec);
92  int flags=0;
93  memset(s, 0, sizeof(AVCodecContext));
94 
95  s->av_class = &av_codec_context_class;
96 
97  s->codec_type = codec ? codec->type : AVMEDIA_TYPE_UNKNOWN;
98  if (codec) {
99  s->codec = codec;
100  s->codec_id = codec->id;
101  }
102 
103  if(s->codec_type == AVMEDIA_TYPE_AUDIO)
105  else if(s->codec_type == AVMEDIA_TYPE_VIDEO)
107  else if(s->codec_type == AVMEDIA_TYPE_SUBTITLE)
110 
111  av_channel_layout_uninit(&s->ch_layout);
112 
113  s->time_base = (AVRational){0,1};
114  s->framerate = (AVRational){ 0, 1 };
115  s->pkt_timebase = (AVRational){ 0, 1 };
116  s->get_buffer2 = avcodec_default_get_buffer2;
117  s->get_format = avcodec_default_get_format;
118  s->get_encode_buffer = avcodec_default_get_encode_buffer;
119  s->execute = avcodec_default_execute;
120  s->execute2 = avcodec_default_execute2;
121  s->sample_aspect_ratio = (AVRational){0,1};
122  s->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
123  s->pix_fmt = AV_PIX_FMT_NONE;
124  s->sw_pix_fmt = AV_PIX_FMT_NONE;
125  s->sample_fmt = AV_SAMPLE_FMT_NONE;
126 
127  s->reordered_opaque = AV_NOPTS_VALUE;
128  if(codec && codec2->priv_data_size){
129  s->priv_data = av_mallocz(codec2->priv_data_size);
130  if (!s->priv_data)
131  return AVERROR(ENOMEM);
132  if(codec->priv_class){
133  *(const AVClass**)s->priv_data = codec->priv_class;
134  av_opt_set_defaults(s->priv_data);
135  }
136  }
137  if (codec && codec2->defaults) {
138  int ret;
139  const FFCodecDefault *d = codec2->defaults;
140  while (d->key) {
141  ret = av_opt_set(s, d->key, d->value, 0);
142  av_assert0(ret >= 0);
143  d++;
144  }
145  }
146  return 0;
147 }
148 
150 {
151  AVCodecContext *avctx= av_malloc(sizeof(AVCodecContext));
152 
153  if (!avctx)
154  return NULL;
155 
156  if (init_context_defaults(avctx, codec) < 0) {
157  av_free(avctx);
158  return NULL;
159  }
160 
161  return avctx;
162 }
163 
165 {
166  AVCodecContext *avctx = *pavctx;
167 
168  if (!avctx)
169  return;
170 
171  avcodec_close(avctx);
172 
173  av_freep(&avctx->extradata);
174  av_freep(&avctx->subtitle_header);
175  av_freep(&avctx->intra_matrix);
176  av_freep(&avctx->inter_matrix);
177  av_freep(&avctx->rc_override);
179 
180  av_freep(pavctx);
181 }
182 
184 {
185  return &av_codec_context_class;
186 }
187 
188 #if FF_API_GET_FRAME_CLASS
190 #define FOFFSET(x) offsetof(AVFrame,x)
191 
192 static const AVOption frame_options[]={
193 {"best_effort_timestamp", "", FOFFSET(best_effort_timestamp), AV_OPT_TYPE_INT64, {.i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, 0},
194 {"pkt_pos", "", FOFFSET(pkt_pos), AV_OPT_TYPE_INT64, {.i64 = -1 }, INT64_MIN, INT64_MAX, 0},
195 {"pkt_size", "", FOFFSET(pkt_size), AV_OPT_TYPE_INT64, {.i64 = -1 }, INT64_MIN, INT64_MAX, 0},
196 {"sample_aspect_ratio", "", FOFFSET(sample_aspect_ratio), AV_OPT_TYPE_RATIONAL, {.dbl = 0 }, 0, INT_MAX, 0},
197 {"width", "", FOFFSET(width), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
198 {"height", "", FOFFSET(height), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
199 {"format", "", FOFFSET(format), AV_OPT_TYPE_INT, {.i64 = -1 }, 0, INT_MAX, 0},
200 #if FF_API_OLD_CHANNEL_LAYOUT
201 {"channel_layout", "", FOFFSET(channel_layout), AV_OPT_TYPE_INT64, {.i64 = 0 }, 0, INT64_MAX, 0},
202 #endif
203 {"sample_rate", "", FOFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
204 {NULL},
205 };
206 
207 static const AVClass av_frame_class = {
208  .class_name = "AVFrame",
209  .item_name = NULL,
210  .option = frame_options,
211  .version = LIBAVUTIL_VERSION_INT,
212 };
213 
215 {
216  return &av_frame_class;
217 }
219 #endif
220 
221 #define SROFFSET(x) offsetof(AVSubtitleRect,x)
222 
224 {"x", "", SROFFSET(x), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
225 {"y", "", SROFFSET(y), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
226 {"w", "", SROFFSET(w), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
227 {"h", "", SROFFSET(h), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
228 {"type", "", SROFFSET(type), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, 0},
229 {"flags", "", SROFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, 1, 0, "flags"},
230 {"forced", "", SROFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, 1, 0},
231 {NULL},
232 };
233 
235  .class_name = "AVSubtitleRect",
236  .item_name = NULL,
237  .option = subtitle_rect_options,
238  .version = LIBAVUTIL_VERSION_INT,
239 };
240 
242 {
243  return &av_subtitle_rect_class;
244 }
avcodec_close
av_cold int avcodec_close(AVCodecContext *avctx)
Close a given AVCodecContext and free all the data associated with it (but not the AVCodecContext its...
Definition: avcodec.c:434
AVCodec
AVCodec.
Definition: codec.h:204
FF_ENABLE_DEPRECATION_WARNINGS
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:82
AVMEDIA_TYPE_SUBTITLE
@ AVMEDIA_TYPE_SUBTITLE
Definition: avutil.h:204
FFCodec::defaults
const FFCodecDefault * defaults
Private codec-specific defaults.
Definition: codec_internal.h:160
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
opt.h
AV_CLASS_CATEGORY_DECODER
@ AV_CLASS_CATEGORY_DECODER
Definition: log.h:35
AV_OPT_FLAG_VIDEO_PARAM
#define AV_OPT_FLAG_VIDEO_PARAM
Definition: opt.h:284
av_opt_set_defaults
void av_opt_set_defaults(void *s)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1459
options_table.h
AVCodec::priv_class
const AVClass * priv_class
AVClass for the private context.
Definition: codec.h:236
AVCodecContext::intra_matrix
uint16_t * intra_matrix
custom intra quantization matrix Must be allocated with the av_malloc() family of functions,...
Definition: avcodec.h:883
w
uint8_t w
Definition: llviddspenc.c:38
AVOption
AVOption.
Definition: opt.h:251
FFCodec
Definition: codec_internal.h:119
AVCodecContext::subtitle_header
uint8_t * subtitle_header
Header containing style information for text subtitles.
Definition: avcodec.h:1708
avcodec_default_get_format
enum AVPixelFormat avcodec_default_get_format(struct AVCodecContext *s, const enum AVPixelFormat *fmt)
Definition: decode.c:935
AV_OPT_TYPE_RATIONAL
@ AV_OPT_TYPE_RATIONAL
Definition: opt.h:230
sample_rate
sample_rate
Definition: ffmpeg_filter.c:156
av_malloc
#define av_malloc(s)
Definition: tableprint_vlc.h:30
FFCodec::priv_data_size
int priv_data_size
Definition: codec_internal.h:137
FFCodecDefault
Definition: codec_internal.h:89
AVCodecContext::codec
const struct AVCodec * codec
Definition: avcodec.h:407
AVCodecContext::ch_layout
AVChannelLayout ch_layout
Audio channel layout.
Definition: avcodec.h:2059
av_codec_context_class
static const AVClass av_codec_context_class
Definition: options.c:77
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
init_context_defaults
static int init_context_defaults(AVCodecContext *s, const AVCodec *codec)
Definition: options.c:89
av_opt_set
int av_opt_set(void *obj, const char *name, const char *val, int search_flags)
Definition: opt.c:487
subtitle_rect_options
static const AVOption subtitle_rect_options[]
Definition: options.c:223
avassert.h
avcodec_alloc_context3
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
Definition: options.c:149
width
#define width
av_subtitle_rect_class
static const AVClass av_subtitle_rect_class
Definition: options.c:234
s
#define s(width, name)
Definition: cbs_vp9.c:256
format
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 format(the sample packing is implied by the sample format) and sample rate. The lists are not just lists
AV_CHANNEL_ORDER_UNSPEC
@ AV_CHANNEL_ORDER_UNSPEC
Only the channel count is specified, without any further information about the channel order.
Definition: channel_layout.h:106
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
AV_OPT_TYPE_INT64
@ AV_OPT_TYPE_INT64
Definition: opt.h:226
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
AV_OPT_FLAG_AUDIO_PARAM
#define AV_OPT_FLAG_AUDIO_PARAM
Definition: opt.h:283
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
avcodec_get_class
const AVClass * avcodec_get_class(void)
Get the AVClass for AVCodecContext.
Definition: options.c:183
NULL
#define NULL
Definition: coverity.c:32
AVCodec::type
enum AVMediaType type
Definition: codec.h:217
avcodec_free_context
void avcodec_free_context(AVCodecContext **pavctx)
Free the codec context and everything associated with it and write NULL to the provided pointer.
Definition: options.c:164
AVRational
Rational number (pair of numerator and denominator).
Definition: rational.h:58
codec_child_next
static void * codec_child_next(void *obj, void *prev)
Definition: options.c:50
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
avcodec_get_subtitle_rect_class
const AVClass * avcodec_get_subtitle_rect_class(void)
Get the AVClass for AVSubtitleRect.
Definition: options.c:241
av_channel_layout_uninit
void av_channel_layout_uninit(AVChannelLayout *channel_layout)
Free any allocated data in the channel layout and reset the channel count to 0.
Definition: channel_layout.c:630
av_codec_is_decoder
int av_codec_is_decoder(const AVCodec *codec)
Definition: utils.c:83
AVCodecContext::rc_override
RcOverride * rc_override
Definition: avcodec.h:1216
codec_internal.h
codec_child_class_iterate
static const AVClass * codec_child_class_iterate(void **iter)
Definition: options.c:58
AVClass::category
AVClassCategory category
Category used for visualization (like color) This is only set if the category is equal for all object...
Definition: log.h:114
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:56
AV_NOPTS_VALUE
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
avcodec_get_frame_class
const AVClass * avcodec_get_frame_class(void)
Definition: options.c:214
ffcodec
static const av_always_inline FFCodec * ffcodec(const AVCodec *codec)
Definition: codec_internal.h:317
av_opt_set_defaults2
void av_opt_set_defaults2(void *s, int mask, int flags)
Set the values of all AVOption fields to their default values.
Definition: opt.c:1464
AVMEDIA_TYPE_UNKNOWN
@ AVMEDIA_TYPE_UNKNOWN
Usually treated as AVMEDIA_TYPE_DATA.
Definition: avutil.h:200
height
#define height
avcodec_default_execute
int avcodec_default_execute(AVCodecContext *c, int(*func)(AVCodecContext *c2, void *arg2), void *arg, int *ret, int count, int size)
Definition: avcodec.c:45
AVCodec::id
enum AVCodecID id
Definition: codec.h:218
avcodec_default_get_buffer2
int avcodec_default_get_buffer2(AVCodecContext *s, AVFrame *frame, int flags)
The default callback for AVCodecContext.get_buffer2().
Definition: get_buffer.c:282
SROFFSET
#define SROFFSET(x)
Definition: options.c:221
AVClassCategory
AVClassCategory
Definition: log.h:28
avcodec_default_execute2
int avcodec_default_execute2(AVCodecContext *c, int(*func)(AVCodecContext *c2, void *arg2, int jobnr, int threadnr), void *arg, int *ret, int count)
Definition: avcodec.c:58
AVCodecContext::extradata
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
Definition: avcodec.h:499
internal.h
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:264
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
av_codec_iterate
const AVCodec * av_codec_iterate(void **opaque)
Iterate over all registered codecs.
Definition: allcodecs.c:897
avcodec.h
frame_options
static const AVOption frame_options[]
Definition: options.c:192
ret
ret
Definition: filter_design.txt:187
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:71
get_category
static AVClassCategory get_category(void *ptr)
Definition: options.c:68
AVCodecContext
main external API structure.
Definition: avcodec.h:398
AV_PIX_FMT_NONE
@ AV_PIX_FMT_NONE
Definition: pixfmt.h:65
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:225
FF_DISABLE_DEPRECATION_WARNINGS
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:81
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
mem.h
AV_OPT_FLAG_SUBTITLE_PARAM
#define AV_OPT_FLAG_SUBTITLE_PARAM
Definition: opt.h:285
av_free
#define av_free(p)
Definition: tableprint_vlc.h:33
av_frame_class
static const AVClass av_frame_class
Definition: options.c:207
avcodec_default_get_encode_buffer
int avcodec_default_get_encode_buffer(AVCodecContext *s, AVPacket *pkt, int flags)
The default callback for AVCodecContext.get_encode_buffer().
Definition: encode.c:57
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
AVCodecContext::inter_matrix
uint16_t * inter_matrix
custom inter quantization matrix Must be allocated with the av_malloc() family of functions,...
Definition: avcodec.h:892
d
d
Definition: ffmpeg_filter.c:156
AV_OPT_TYPE_FLAGS
@ AV_OPT_TYPE_FLAGS
Definition: opt.h:224
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
avcodec_options
static const AVOption avcodec_options[]
Definition: options_table.h:47
FOFFSET
#define FOFFSET(x)
Definition: options.c:190
AV_CLASS_CATEGORY_ENCODER
@ AV_CLASS_CATEGORY_ENCODER
Definition: log.h:34
h
h
Definition: vp9dsp_template.c:2038
context_to_name
FF_DISABLE_DEPRECATION_WARNINGS static const FF_ENABLE_DEPRECATION_WARNINGS char * context_to_name(void *ptr)
Definition: options.c:41