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[libav.git] / libavfilter / avfilter.h
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1/*
2 * Filter layer
3 * copyright (c) 2007 Bobby Bingham
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#ifndef FFMPEG_AVFILTER_H
23#define FFMPEG_AVFILTER_H
24
a9c81431 25#include <stddef.h>
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26#include "avcodec.h"
27
28typedef struct AVFilterContext AVFilterContext;
29typedef struct AVFilterLink AVFilterLink;
30typedef struct AVFilterPad AVFilterPad;
31
32/* TODO: look for other flags which may be useful in this structure (interlace
33 * flags, etc)
34 */
35/**
36 * A reference-counted picture data type used by the filter system. Filters
37 * should not store pointers to this structure directly, but instead use the
38 * AVFilterPicRef structure below
39 */
40typedef struct AVFilterPic
41{
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42 uint8_t *data[4]; ///< picture data for each plane
43 int linesize[4]; ///< number of bytes per line
44 enum PixelFormat format; ///< colorspace
a5cbb2f4 45
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46 unsigned refcount; ///< number of references to this image
47
48 /** private data to be used by a custom free function */
a5cbb2f4 49 void *priv;
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50 /**
51 * A pointer to the function to deallocate this image if the default
52 * function is not sufficient. This could, for example, add the memory
53 * back into a memory pool to be reused later without the overhead of
54 * reallocating it from scratch.
55 */
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56 void (*free)(struct AVFilterPic *pic);
57} AVFilterPic;
58
59/**
60 * A reference to an AVFilterPic. Since filters can manipulate the origin of
61 * a picture to, for example, crop image without any memcpy, the picture origin
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62 * and dimensions are per-reference properties. Linesize is also useful for
63 * image flipping, frame to field filters, etc, and so is also per-reference.
a5cbb2f4 64 *
1a18860a 65 * TODO: add anything necessary for frame reordering
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66 */
67typedef struct AVFilterPicRef
68{
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69 AVFilterPic *pic; ///< the picture that this is a reference to
70 uint8_t *data[4]; ///< picture data for each plane
71 int linesize[4]; ///< number of bytes per line
72 int w; ///< image width
73 int h; ///< image height
a5cbb2f4 74
056f0431 75 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
1a18860a 76
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77 AVRational pixel_aspect; ///< pixel aspect ratio
78
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79 int perms; ///< permissions
80#define AV_PERM_READ 0x01 ///< can read from the buffer
81#define AV_PERM_WRITE 0x02 ///< can write to the buffer
82#define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
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83#define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
84#define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
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85} AVFilterPicRef;
86
87/**
88 * Add a new reference to a picture.
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89 * @param ref An existing reference to the picture
90 * @param pmask A bitmask containing the allowable permissions in the new
91 * reference
92 * @return A new reference to the picture with the same properties as the
93 * old, excluding any permissions denied by pmask
a5cbb2f4 94 */
16415eaf 95AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
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96
97/**
98 * Remove a reference to a picture. If this is the last reference to the
99 * picture, the picture itself is also automatically freed.
100 * @param ref Reference to the picture.
101 */
102void avfilter_unref_pic(AVFilterPicRef *ref);
103
13ff8fd0 104/**
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105 * A list of supported formats for one end of a filter link. This is used
106 * during the format negotiation process to try to pick the best format to
107 * use to minimize the number of necessary conversions. Each filter gives a
108 * list of the formats supported by each input and output pad. The list
109 * given for each pad need not be distinct - they may be references to the
110 * same list of formats, as is often the case when a filter supports multiple
111 * formats, but will always outut the same format as it is given in input.
112 *
113 * In this way, a list of possible input formats and a list of possible
114 * output formats are associated with each link. When a set of formats is
115 * negotiated over a link, the input and output lists are merged to form a
116 * new list containing only the common elements of each list. In the case
117 * that there were no common elements, a format conversion is necessary.
118 * Otherwise, the lists are merged, and all other links which reference
119 * either of the format lists involved in the merge are also affected.
120 *
121 * For example, consider the filter chain:
122 * filter (a) --> (b) filter (b) --> (c) filter
123 *
124 * where the letters in parenthesis indicate a list of formats supported on
125 * the input or output of the link. Suppose the lists are as follows:
126 * (a) = {A, B}
127 * (b) = {A, B, C}
128 * (c) = {B, C}
129 *
130 * First, the first link's lists are merged, yielding:
131 * filter (a) --> (a) filter (a) --> (c) filter
132 *
133 * Notice that format list (b) now refers to the same list as filter list (a).
134 * Next, the lists for the second link are merged, yielding:
135 * filter (a) --> (a) filter (a) --> (a) filter
136 *
137 * where (a) = {B}.
138 *
139 * Unfortunately, when the format lists at the two ends of a link are merged,
140 * we must ensure that all links which reference either pre-merge format list
141 * get updated as well. Therefore, we have the format list structure store a
142 * pointer to each of the pointers to itself.
143 */
144typedef struct AVFilterFormats AVFilterFormats;
145struct AVFilterFormats
146{
147 unsigned format_count; ///< number of formats
148 int *formats; ///< list of formats
149
150 unsigned refcount; ///< number of references to this list
151 AVFilterFormats ***refs; ///< references to this list
152};
153
154/**
155 * Helper function to create a list of supported formats. This is intended
156 * for use in AVFilter->query_formats().
157 * @param len The number of formats supported
158 * @param ... A list of the supported formats
159 * @return The format list, with no existing references
160 */
161AVFilterFormats *avfilter_make_format_list(int len, ...);
162
163/**
164 * Returns a fairly comprehensive list of colorspaces which are supported by
165 * many of the included filters. This is not truly "all" the colorspaces, but
166 * it is most of them, and it is the most commonly supported large subset.
167 */
168AVFilterFormats *avfilter_all_colorspaces(void);
169
170/**
171 * If a and b share at least one common format, they are merged into a new
172 * format list which is returned. All the references to a and b are updated
173 * to point to this new list, and a and b are deallocated.
174 *
175 * If a and b do not share any common formats, neither is modified, and NULL
176 * is returned.
177 */
178AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
179
180/** Adds *ref as a new reference to f */
181void avfilter_formats_ref(AVFilterFormats *f, AVFilterFormats **ref);
182
183/**
184 * Remove *ref as a reference to the format list it currently points to,
185 * deallocate that list if this was the last reference, and set *ref to NULL
186 */
187void avfilter_formats_unref(AVFilterFormats **ref);
188
189/**
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190 * A filter pad used for either input or output
191 */
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192struct AVFilterPad
193{
194 /**
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195 * Pad name. The name is unique among inputs and among outputs, but an
196 * input may have the same name as an output. This may be NULL if this
197 * pad has no need to ever be referenced by name.
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198 */
199 char *name;
200
201 /**
202 * AVFilterPad type. Only video supported now, hopefully someone will
203 * add audio in the future.
204 */
205 int type;
13ff8fd0 206#define AV_PAD_VIDEO 0 ///< video pad
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207
208 /**
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209 * Minimum required permissions on incoming buffers. Any buffers with
210 * insufficient permissions will be automatically copied by the filter
211 * system to a new buffer which provides the needed access permissions.
212 *
213 * Input pads only.
214 */
215 int min_perms;
216
217 /**
218 * Permissions which are not accepted on incoming buffers. Any buffer
219 * which has any of these permissions set be automatically copied by the
220 * filter system to a new buffer which does not have those permissions.
221 * This can be used to easily disallow buffers with AV_PERM_REUSE.
222 *
223 * Input pads only.
224 */
225 int rej_perms;
226
227 /**
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228 * Callback called before passing the first slice of a new frame. If
229 * NULL, the filter layer will default to storing a reference to the
230 * picture inside the link structure.
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231 *
232 * Input video pads only.
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233 */
234 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
235
236 /**
237 * Callback function to get a buffer. If NULL, the filter system will
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238 * handle buffer requests.
239 *
240 * Input video pads only.
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241 */
242 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
243
244 /**
245 * Callback called after the slices of a frame are completely sent. If
246 * NULL, the filter layer will default to releasing the reference stored
247 * in the link structure during start_frame().
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248 *
249 * Input video pads only.
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250 */
251 void (*end_frame)(AVFilterLink *link);
252
253 /**
254 * Slice drawing callback. This is where a filter receives video data
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255 * and should do its processing.
256 *
257 * Input video pads only.
a5cbb2f4 258 */
72f6d631 259 void (*draw_slice)(AVFilterLink *link, int y, int height);
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260
261 /**
262 * Frame request callback. A call to this should result in at least one
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263 * frame being output over the given link. This should return zero on
264 * success, and another value on error.
265 *
266 * Output video pads only.
a5cbb2f4 267 */
63f64e6f 268 int (*request_frame)(AVFilterLink *link);
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269
270 /**
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271 * Link configuration callback.
272 *
273 * For output pads, this should set the link properties such as
274 * width/height. This should NOT set the format property - that is
275 * negotiated between filters by the filter system using the
276 * query_formats() callback before this function is called.
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277 *
278 * For input pads, this should check the properties of the link, and update
279 * the filter's internal state as necessary.
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280 *
281 * For both input and output filters, this should return zero on success,
282 * and another value on error.
a5cbb2f4 283 */
d3e57c15 284 int (*config_props)(AVFilterLink *link);
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285};
286
13ff8fd0 287/** Default handler for start_frame() for video inputs */
a5cbb2f4 288void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
13ff8fd0 289/** Default handler for end_frame() for video inputs */
a5cbb2f4 290void avfilter_default_end_frame(AVFilterLink *link);
13ff8fd0 291/** Default handler for config_props() for video outputs */
901e6b39 292int avfilter_default_config_output_link(AVFilterLink *link);
13ff8fd0 293/** Default handler for config_props() for video inputs */
85322466 294int avfilter_default_config_input_link (AVFilterLink *link);
13ff8fd0 295/** Default handler for get_video_buffer() for video inputs */
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296AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
297 int perms);
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298/**
299 * A helper for query_formats() which sets all links to the same list of
300 * formats. If there are no links hooked to this filter, the list of formats is
301 * freed.
302 */
303void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
304/** Default handler for query_formats() */
305int avfilter_default_query_formats(AVFilterContext *ctx);
a5cbb2f4 306
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307void avfilter_formats_changeref(AVFilterFormats **oldref,
308 AVFilterFormats **newref);
309
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310/**
311 * Filter definition. This defines the pads a filter contains, and all the
312 * callback functions used to interact with the filter.
313 */
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314typedef struct
315{
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316 char *name; ///< filter name
317 char *author; ///< filter author
a5cbb2f4 318
13ff8fd0 319 int priv_size; ///< size of private data to allocate for the filter
a5cbb2f4 320
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321 /**
322 * Filter initialization function. Args contains the user-supplied
323 * parameters. FIXME: maybe an AVOption-based system would be better?
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324 * opaque is data provided by the code requesting creation of the filter,
325 * and is used to pass data to the filter.
4d96a914 326 */
95bcf498 327 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
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328
329 /**
330 * Filter uninitialization function. Should deallocate any memory held
331 * by the filter, release any picture references, etc. This does not need
332 * to deallocate the AVFilterContext->priv memory itself.
333 */
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334 void (*uninit)(AVFilterContext *ctx);
335
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336 /**
337 * Query formats supported by the filter and its pads. Should set the
338 * in_formats for links connected to its output pads, and out_formats
339 * for links connected to its input pads.
340 *
341 * Should return zero on success.
342 */
343 int (*query_formats)(AVFilterContext *);
344
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345 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
346 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
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347} AVFilter;
348
13ff8fd0 349/** An instance of a filter */
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350struct AVFilterContext
351{
13ff8fd0 352 AVClass *av_class; ///< Needed for av_log()
a5cbb2f4 353
13ff8fd0 354 AVFilter *filter; ///< The AVFilter of which this is an instance
a5cbb2f4 355
13ff8fd0 356 char *name; ///< name of this filter instance
dcea2482 357
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358 unsigned input_count; ///< number of input pads
359 AVFilterPad *input_pads; ///< array of input pads
360 AVFilterLink **inputs; ///< array of pointers to input links
25f8e601 361
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362 unsigned output_count; ///< number of output pads
363 AVFilterPad *output_pads; ///< array of output pads
364 AVFilterLink **outputs; ///< array of pointers to output links
a5cbb2f4 365
13ff8fd0 366 void *priv; ///< private data for use by the filter
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367};
368
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369/**
370 * A links between two filters. This contains pointers to the source and
371 * destination filters between which this link exists, and the indices of
372 * the pads involved. In addition, this link also contains the parameters
373 * which have been negotiated and agreed upon between the filter, such as
374 * image dimensions, format, etc
375 */
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376struct AVFilterLink
377{
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378 AVFilterContext *src; ///< source filter
379 unsigned int srcpad; ///< index of the output pad on the source filter
a5cbb2f4 380
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381 AVFilterContext *dst; ///< dest filter
382 unsigned int dstpad; ///< index of the input pad on the dest filter
a5cbb2f4 383
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384 /** stage of the initialization of the link properties (dimensions, etc) */
385 enum {
386 AVLINK_UNINIT = 0, ///< not started
387 AVLINK_STARTINIT, ///< started, but incomplete
388 AVLINK_INIT ///< complete
389 } init_state;
390
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391 int w; ///< agreed upon image width
392 int h; ///< agreed upon image height
393 enum PixelFormat format; ///< agreed upon image colorspace
a5cbb2f4 394
60bf6ce3 395 /**
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396 * Lists of formats supported by the input and output filters respectively.
397 * These lists are used for negotiating the format to actually be used,
398 * which will be loaded into the format member, above, when chosen.
399 */
400 AVFilterFormats *in_formats;
401 AVFilterFormats *out_formats;
402
403 /**
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404 * The picture reference currently being sent across the link by the source
405 * filter. This is used internally by the filter system to allow
406 * automatic copying of pictures which d not have sufficient permissions
407 * for the destination. This should not be accessed directly by the
408 * filters.
409 */
410 AVFilterPicRef *srcpic;
411
a5cbb2f4 412 AVFilterPicRef *cur_pic;
462f57db 413 AVFilterPicRef *outpic;
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414};
415
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416/**
417 * Link two filters together
418 * @param src The source filter
419 * @param srcpad Index of the output pad on the source filter
420 * @param dst The destination filter
421 * @param dstpad Index of the input pad on the destination filter
422 * @return Zero on success
423 */
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424int avfilter_link(AVFilterContext *src, unsigned srcpad,
425 AVFilterContext *dst, unsigned dstpad);
426
13ff8fd0 427/**
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428 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
429 * @param filter The filter to negotiate the properties for its inputs
d177bd18 430 * @return Zero on successful negotiation
13ff8fd0 431 */
24c4eff6 432int avfilter_config_links(AVFilterContext *filter);
85322466 433
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434/**
435 * Request a picture buffer with a specific set of permissions
436 * @param link The output link to the filter from which the picture will
437 * be requested
438 * @param perms The required access permissions
439 * @return A reference to the picture. This must be unreferenced with
440 * avfilter_unref_pic when you are finished with it.
441 */
a5cbb2f4 442AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
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443
444/**
445 * Request an input frame from the filter at the other end of the link.
446 * @param link The input link
447 * @return Zero on success
448 */
63f64e6f 449int avfilter_request_frame(AVFilterLink *link);
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450
451/**
b42a6a92 452 * Notify the next filter of the start of a frame.
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453 * @param link The output link the frame will be sent over
454 * @param picref A reference to the frame about to be sent. The data for this
455 * frame need only be valid once draw_slice() is called for that
456 * portion. The receiving filter will free this reference when
457 * it no longer needs it.
458 */
a5cbb2f4 459void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
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460
461/**
462 * Notify the next filter that the current frame has finished
463 * @param link The output link the frame was sent over
464 */
a5cbb2f4 465void avfilter_end_frame(AVFilterLink *link);
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466
467/**
468 * Send a slice to the next filter
469 * @param link The output link over which the frame is being sent
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470 * @param y Offset in pixels from the top of the image for this slice
471 * @param h Height of this slice in pixels
472 */
72f6d631 473void avfilter_draw_slice(AVFilterLink *link, int y, int h);
a5cbb2f4 474
13ff8fd0 475/** Initialize the filter system. Registers all builtin filters */
a5cbb2f4 476void avfilter_init(void);
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477
478/** Uninitialize the filter system. Unregisters all filters */
a5cbb2f4 479void avfilter_uninit(void);
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480
481/**
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482 * Register a filter. This is only needed if you plan to use
483 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
484 * filter can still by instantiated with avfilter_open even if it is not
485 * registered.
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486 * @param filter The filter to register
487 */
a5cbb2f4 488void avfilter_register(AVFilter *filter);
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489
490/**
491 * Gets a filter definition matching the given name
492 * @param name The filter name to find
493 * @return The filter definition, if any matching one is registered.
494 * NULL if none found.
495 */
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496AVFilter *avfilter_get_by_name(char *name);
497
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498/**
499 * Create a filter instance
500 * @param filter The filter to create an instance of
501 * @param inst_name Name to give to the new instance. Can be NULL for none.
502 * @return Pointer to the new instance on success. NULL on failure.
503 */
fc815c56 504AVFilterContext *avfilter_open(AVFilter *filter, char *inst_name);
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505
506/**
507 * Initialize a filter
508 * @param filter The filter to initialize
509 * @param args A string of parameters to use when initializing the filter.
510 * The format and meaning of this string varies by filter.
511 * @param opaque Any extra non-string data needed by the filter. The meaning
512 * of this parameter varies by filter.
513 * @return Zero on success
514 */
6e365c57 515int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
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516
517/**
518 * Destroy a filter
519 * @param filter The filter to destroy
520 */
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521void avfilter_destroy(AVFilterContext *filter);
522
13ff8fd0 523/**
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524 * Insert a filter in the middle of an existing link.
525 * @param link The link into which the filter should be inserted
526 * @param filt The filter to be inserted
527 * @param in The input pad on the filter to connect
528 * @param out The output pad on the filter to connect
529 * @return Zero on success
13ff8fd0 530 */
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531int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
532 unsigned in, unsigned out);
d3e57c15 533
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534/**
535 * Insert a new pad
536 * @param idx Insertion point. Pad is inserted at the end if this point
537 * is beyond the end of the list of pads.
538 * @param count Pointer to the number of pads in the list
539 * @param padidx_off Offset within an AVFilterLink structure to the element
540 * to increment when inserting a new pad causes link
541 * numbering to change
542 * @param pads Pointer to the pointer to the beginning of the list of pads
543 * @param links Pointer to the pointer to the beginning of the list of links
544 * @param newpad The new pad to add. A copy is made when adding.
545 */
546void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
547 AVFilterPad **pads, AVFilterLink ***links,
548 AVFilterPad *newpad);
549
550/** insert a new input pad for the filter */
551static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
552 AVFilterPad *p)
553{
554 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
555 &f->input_pads, &f->inputs, p);
556}
557
558/** insert a new output pad for the filter */
559static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
560 AVFilterPad *p)
561{
562 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
563 &f->output_pads, &f->outputs, p);
564}
565
a5cbb2f4 566#endif /* FFMPEG_AVFILTER_H */