8ef93bae2e366346254777a28d4e8aa237075288
[libav.git] / libavfilter / avfilter.h
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 AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
24
25 #include "libavutil/avutil.h"
26
27 #define LIBAVFILTER_VERSION_MAJOR 1
28 #define LIBAVFILTER_VERSION_MINOR 11
29 #define LIBAVFILTER_VERSION_MICRO 0
30
31 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
32 LIBAVFILTER_VERSION_MINOR, \
33 LIBAVFILTER_VERSION_MICRO)
34 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
35 LIBAVFILTER_VERSION_MINOR, \
36 LIBAVFILTER_VERSION_MICRO)
37 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
38
39 #include <stddef.h>
40 #include "libavcodec/avcodec.h"
41
42 /**
43 * Returns the LIBAVFILTER_VERSION_INT constant.
44 */
45 unsigned avfilter_version(void);
46
47 /**
48 * Returns the libavfilter build-time configuration.
49 */
50 const char * avfilter_configuration(void);
51
52 /**
53 * Returns the libavfilter license.
54 */
55 const char * avfilter_license(void);
56
57
58 typedef struct AVFilterContext AVFilterContext;
59 typedef struct AVFilterLink AVFilterLink;
60 typedef struct AVFilterPad AVFilterPad;
61
62 /* TODO: look for other flags which may be useful in this structure (interlace
63 * flags, etc)
64 */
65 /**
66 * A reference-counted picture data type used by the filter system. Filters
67 * should not store pointers to this structure directly, but instead use the
68 * AVFilterPicRef structure below.
69 */
70 typedef struct AVFilterPic
71 {
72 uint8_t *data[4]; ///< picture data for each plane
73 int linesize[4]; ///< number of bytes per line
74 enum PixelFormat format; ///< colorspace
75
76 unsigned refcount; ///< number of references to this image
77
78 /** private data to be used by a custom free function */
79 void *priv;
80 /**
81 * A pointer to the function to deallocate this image if the default
82 * function is not sufficient. This could, for example, add the memory
83 * back into a memory pool to be reused later without the overhead of
84 * reallocating it from scratch.
85 */
86 void (*free)(struct AVFilterPic *pic);
87
88 int w, h; ///< width and height of the allocated buffer
89 } AVFilterPic;
90
91 /**
92 * A reference to an AVFilterPic. Since filters can manipulate the origin of
93 * a picture to, for example, crop image without any memcpy, the picture origin
94 * and dimensions are per-reference properties. Linesize is also useful for
95 * image flipping, frame to field filters, etc, and so is also per-reference.
96 *
97 * TODO: add anything necessary for frame reordering
98 */
99 typedef struct AVFilterPicRef
100 {
101 AVFilterPic *pic; ///< the picture that this is a reference to
102 uint8_t *data[4]; ///< picture data for each plane
103 int linesize[4]; ///< number of bytes per line
104 int w; ///< image width
105 int h; ///< image height
106
107 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
108
109 AVRational pixel_aspect; ///< pixel aspect ratio
110
111 int perms; ///< permissions
112 #define AV_PERM_READ 0x01 ///< can read from the buffer
113 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
114 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
115 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
116 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
117 } AVFilterPicRef;
118
119 /**
120 * Adds a new reference to a picture.
121 * @param ref an existing reference to the picture
122 * @param pmask a bitmask containing the allowable permissions in the new
123 * reference
124 * @return a new reference to the picture with the same properties as the
125 * old, excluding any permissions denied by pmask
126 */
127 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
128
129 /**
130 * Removes a reference to a picture. If this is the last reference to the
131 * picture, the picture itself is also automatically freed.
132 * @param ref reference to the picture
133 */
134 void avfilter_unref_pic(AVFilterPicRef *ref);
135
136 /**
137 * A list of supported formats for one end of a filter link. This is used
138 * during the format negotiation process to try to pick the best format to
139 * use to minimize the number of necessary conversions. Each filter gives a
140 * list of the formats supported by each input and output pad. The list
141 * given for each pad need not be distinct - they may be references to the
142 * same list of formats, as is often the case when a filter supports multiple
143 * formats, but will always output the same format as it is given in input.
144 *
145 * In this way, a list of possible input formats and a list of possible
146 * output formats are associated with each link. When a set of formats is
147 * negotiated over a link, the input and output lists are merged to form a
148 * new list containing only the common elements of each list. In the case
149 * that there were no common elements, a format conversion is necessary.
150 * Otherwise, the lists are merged, and all other links which reference
151 * either of the format lists involved in the merge are also affected.
152 *
153 * For example, consider the filter chain:
154 * filter (a) --> (b) filter (b) --> (c) filter
155 *
156 * where the letters in parenthesis indicate a list of formats supported on
157 * the input or output of the link. Suppose the lists are as follows:
158 * (a) = {A, B}
159 * (b) = {A, B, C}
160 * (c) = {B, C}
161 *
162 * First, the first link's lists are merged, yielding:
163 * filter (a) --> (a) filter (a) --> (c) filter
164 *
165 * Notice that format list (b) now refers to the same list as filter list (a).
166 * Next, the lists for the second link are merged, yielding:
167 * filter (a) --> (a) filter (a) --> (a) filter
168 *
169 * where (a) = {B}.
170 *
171 * Unfortunately, when the format lists at the two ends of a link are merged,
172 * we must ensure that all links which reference either pre-merge format list
173 * get updated as well. Therefore, we have the format list structure store a
174 * pointer to each of the pointers to itself.
175 */
176 typedef struct AVFilterFormats AVFilterFormats;
177 struct AVFilterFormats
178 {
179 unsigned format_count; ///< number of formats
180 enum PixelFormat *formats; ///< list of pixel formats
181
182 unsigned refcount; ///< number of references to this list
183 AVFilterFormats ***refs; ///< references to this list
184 };
185
186 /**
187 * Creates a list of supported formats. This is intended for use in
188 * AVFilter->query_formats().
189 * @param pix_fmt list of pixel formats, terminated by PIX_FMT_NONE
190 * @return the format list, with no existing references
191 */
192 AVFilterFormats *avfilter_make_format_list(const enum PixelFormat *pix_fmts);
193
194 /**
195 * Returns a list of all colorspaces supported by FFmpeg.
196 */
197 AVFilterFormats *avfilter_all_colorspaces(void);
198
199 /**
200 * Returns a format list which contains the intersection of the formats of
201 * a and b. Also, all the references of a, all the references of b, and
202 * a and b themselves will be deallocated.
203 *
204 * If a and b do not share any common formats, neither is modified, and NULL
205 * is returned.
206 */
207 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
208
209 /**
210 * Adds *ref as a new reference to formats.
211 * That is the pointers will point like in the ascii art below:
212 * ________
213 * |formats |<--------.
214 * | ____ | ____|___________________
215 * | |refs| | | __|_
216 * | |* * | | | | | | AVFilterLink
217 * | |* *--------->|*ref|
218 * | |____| | | |____|
219 * |________| |________________________
220 */
221 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
222
223 /**
224 * Removes *ref as a reference to the format list it currently points to,
225 * deallocates that list if this was the last reference, and sets *ref to NULL.
226 *
227 * Before After
228 * ________ ________ NULL
229 * |formats |<--------. |formats | ^
230 * | ____ | ____|________________ | ____ | ____|________________
231 * | |refs| | | __|_ | |refs| | | __|_
232 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
233 * | |* *--------->|*ref| | |* | | | |*ref|
234 * | |____| | | |____| | |____| | | |____|
235 * |________| |_____________________ |________| |_____________________
236 */
237 void avfilter_formats_unref(AVFilterFormats **ref);
238
239 /**
240 *
241 * Before After
242 * ________ ________
243 * |formats |<---------. |formats |<---------.
244 * | ____ | ___|___ | ____ | ___|___
245 * | |refs| | | | | | |refs| | | | | NULL
246 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
247 * | |* * | | |_______| | |* * | | |_______| ___|___
248 * | |____| | | |____| | | | |
249 * |________| |________| |*oldref|
250 * |_______|
251 */
252 void avfilter_formats_changeref(AVFilterFormats **oldref,
253 AVFilterFormats **newref);
254
255 /**
256 * A filter pad used for either input or output.
257 */
258 struct AVFilterPad
259 {
260 /**
261 * Pad name. The name is unique among inputs and among outputs, but an
262 * input may have the same name as an output. This may be NULL if this
263 * pad has no need to ever be referenced by name.
264 */
265 const char *name;
266
267 /**
268 * AVFilterPad type. Only video supported now, hopefully someone will
269 * add audio in the future.
270 */
271 enum CodecType type;
272
273 /**
274 * Minimum required permissions on incoming buffers. Any buffer with
275 * insufficient permissions will be automatically copied by the filter
276 * system to a new buffer which provides the needed access permissions.
277 *
278 * Input pads only.
279 */
280 int min_perms;
281
282 /**
283 * Permissions which are not accepted on incoming buffers. Any buffer
284 * which has any of these permissions set will be automatically copied
285 * by the filter system to a new buffer which does not have those
286 * permissions. This can be used to easily disallow buffers with
287 * AV_PERM_REUSE.
288 *
289 * Input pads only.
290 */
291 int rej_perms;
292
293 /**
294 * Callback called before passing the first slice of a new frame. If
295 * NULL, the filter layer will default to storing a reference to the
296 * picture inside the link structure.
297 *
298 * Input video pads only.
299 */
300 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
301
302 /**
303 * Callback function to get a buffer. If NULL, the filter system will
304 * use avfilter_default_get_video_buffer().
305 *
306 * Input video pads only.
307 */
308 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
309
310 /**
311 * Callback called after the slices of a frame are completely sent. If
312 * NULL, the filter layer will default to releasing the reference stored
313 * in the link structure during start_frame().
314 *
315 * Input video pads only.
316 */
317 void (*end_frame)(AVFilterLink *link);
318
319 /**
320 * Slice drawing callback. This is where a filter receives video data
321 * and should do its processing.
322 *
323 * Input video pads only.
324 */
325 void (*draw_slice)(AVFilterLink *link, int y, int height);
326
327 /**
328 * Frame poll callback. This returns the number of immediately available
329 * frames. It should return a positive value if the next request_frame()
330 * is guaranteed to return one frame (with no delay).
331 *
332 * Defaults to just calling the source poll_frame() method.
333 *
334 * Output video pads only.
335 */
336 int (*poll_frame)(AVFilterLink *link);
337
338 /**
339 * Frame request callback. A call to this should result in at least one
340 * frame being output over the given link. This should return zero on
341 * success, and another value on error.
342 *
343 * Output video pads only.
344 */
345 int (*request_frame)(AVFilterLink *link);
346
347 /**
348 * Link configuration callback.
349 *
350 * For output pads, this should set the link properties such as
351 * width/height. This should NOT set the format property - that is
352 * negotiated between filters by the filter system using the
353 * query_formats() callback before this function is called.
354 *
355 * For input pads, this should check the properties of the link, and update
356 * the filter's internal state as necessary.
357 *
358 * For both input and output filters, this should return zero on success,
359 * and another value on error.
360 */
361 int (*config_props)(AVFilterLink *link);
362 };
363
364 /** default handler for start_frame() for video inputs */
365 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
366 /** default handler for draw_slice() for video inputs */
367 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h);
368 /** default handler for end_frame() for video inputs */
369 void avfilter_default_end_frame(AVFilterLink *link);
370 /** default handler for config_props() for video outputs */
371 int avfilter_default_config_output_link(AVFilterLink *link);
372 /** default handler for config_props() for video inputs */
373 int avfilter_default_config_input_link (AVFilterLink *link);
374 /** default handler for get_video_buffer() for video inputs */
375 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
376 int perms, int w, int h);
377 /**
378 * A helper for query_formats() which sets all links to the same list of
379 * formats. If there are no links hooked to this filter, the list of formats is
380 * freed.
381 */
382 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
383 /** Default handler for query_formats() */
384 int avfilter_default_query_formats(AVFilterContext *ctx);
385
386 /**
387 * Filter definition. This defines the pads a filter contains, and all the
388 * callback functions used to interact with the filter.
389 */
390 typedef struct AVFilter
391 {
392 const char *name; ///< filter name
393
394 int priv_size; ///< size of private data to allocate for the filter
395
396 /**
397 * Filter initialization function. Args contains the user-supplied
398 * parameters. FIXME: maybe an AVOption-based system would be better?
399 * opaque is data provided by the code requesting creation of the filter,
400 * and is used to pass data to the filter.
401 */
402 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
403
404 /**
405 * Filter uninitialization function. Should deallocate any memory held
406 * by the filter, release any picture references, etc. This does not need
407 * to deallocate the AVFilterContext->priv memory itself.
408 */
409 void (*uninit)(AVFilterContext *ctx);
410
411 /**
412 * Query formats supported by the filter and its pads. Should set the
413 * in_formats for links connected to its output pads, and out_formats
414 * for links connected to its input pads.
415 *
416 * Should return zero on success.
417 */
418 int (*query_formats)(AVFilterContext *);
419
420 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
421 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
422
423 /**
424 * A description for the filter. You should use the
425 * NULL_IF_CONFIG_SMALL() macro to define it.
426 */
427 const char *description;
428 } AVFilter;
429
430 /** An instance of a filter */
431 struct AVFilterContext
432 {
433 const AVClass *av_class; ///< needed for av_log()
434
435 AVFilter *filter; ///< the AVFilter of which this is an instance
436
437 char *name; ///< name of this filter instance
438
439 unsigned input_count; ///< number of input pads
440 AVFilterPad *input_pads; ///< array of input pads
441 AVFilterLink **inputs; ///< array of pointers to input links
442
443 unsigned output_count; ///< number of output pads
444 AVFilterPad *output_pads; ///< array of output pads
445 AVFilterLink **outputs; ///< array of pointers to output links
446
447 void *priv; ///< private data for use by the filter
448 };
449
450 /**
451 * A link between two filters. This contains pointers to the source and
452 * destination filters between which this link exists, and the indexes of
453 * the pads involved. In addition, this link also contains the parameters
454 * which have been negotiated and agreed upon between the filter, such as
455 * image dimensions, format, etc.
456 */
457 struct AVFilterLink
458 {
459 AVFilterContext *src; ///< source filter
460 unsigned int srcpad; ///< index of the output pad on the source filter
461
462 AVFilterContext *dst; ///< dest filter
463 unsigned int dstpad; ///< index of the input pad on the dest filter
464
465 /** stage of the initialization of the link properties (dimensions, etc) */
466 enum {
467 AVLINK_UNINIT = 0, ///< not started
468 AVLINK_STARTINIT, ///< started, but incomplete
469 AVLINK_INIT ///< complete
470 } init_state;
471
472 int w; ///< agreed upon image width
473 int h; ///< agreed upon image height
474 enum PixelFormat format; ///< agreed upon image colorspace
475
476 /**
477 * Lists of formats supported by the input and output filters respectively.
478 * These lists are used for negotiating the format to actually be used,
479 * which will be loaded into the format member, above, when chosen.
480 */
481 AVFilterFormats *in_formats;
482 AVFilterFormats *out_formats;
483
484 /**
485 * The picture reference currently being sent across the link by the source
486 * filter. This is used internally by the filter system to allow
487 * automatic copying of pictures which do not have sufficient permissions
488 * for the destination. This should not be accessed directly by the
489 * filters.
490 */
491 AVFilterPicRef *srcpic;
492
493 AVFilterPicRef *cur_pic;
494 AVFilterPicRef *outpic;
495 };
496
497 /**
498 * Links two filters together.
499 * @param src the source filter
500 * @param srcpad index of the output pad on the source filter
501 * @param dst the destination filter
502 * @param dstpad index of the input pad on the destination filter
503 * @return zero on success
504 */
505 int avfilter_link(AVFilterContext *src, unsigned srcpad,
506 AVFilterContext *dst, unsigned dstpad);
507
508 /**
509 * Negotiates the colorspace, dimensions, etc of all inputs to a filter.
510 * @param filter the filter to negotiate the properties for its inputs
511 * @return zero on successful negotiation
512 */
513 int avfilter_config_links(AVFilterContext *filter);
514
515 /**
516 * Requests a picture buffer with a specific set of permissions.
517 * @param link the output link to the filter from which the picture will
518 * be requested
519 * @param perms the required access permissions
520 * @param w the minimum width of the buffer to allocate
521 * @param h the minimum height of the buffer to allocate
522 * @return A reference to the picture. This must be unreferenced with
523 * avfilter_unref_pic when you are finished with it.
524 */
525 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
526 int w, int h);
527
528 /**
529 * Requests an input frame from the filter at the other end of the link.
530 * @param link the input link
531 * @return zero on success
532 */
533 int avfilter_request_frame(AVFilterLink *link);
534
535 /**
536 * Polls a frame from the filter chain.
537 * @param link the input link
538 * @return the number of immediately available frames, a negative
539 * number in case of error
540 */
541 int avfilter_poll_frame(AVFilterLink *link);
542
543 /**
544 * Notifies the next filter of the start of a frame.
545 * @param link the output link the frame will be sent over
546 * @param picref A reference to the frame about to be sent. The data for this
547 * frame need only be valid once draw_slice() is called for that
548 * portion. The receiving filter will free this reference when
549 * it no longer needs it.
550 */
551 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
552
553 /**
554 * Notifies the next filter that the current frame has finished.
555 * @param link the output link the frame was sent over
556 */
557 void avfilter_end_frame(AVFilterLink *link);
558
559 /**
560 * Sends a slice to the next filter.
561 *
562 * Slices have to be provided in sequential order, either in
563 * top-bottom or bottom-top order. If slices are provided in
564 * non-sequential order the behavior of the function is undefined.
565 *
566 * @param link the output link over which the frame is being sent
567 * @param y offset in pixels from the top of the image for this slice
568 * @param h height of this slice in pixels
569 */
570 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
571
572 /** Initializes the filter system. Registers all builtin filters. */
573 void avfilter_register_all(void);
574
575 /** Uninitializes the filter system. Unregisters all filters. */
576 void avfilter_uninit(void);
577
578 /**
579 * Registers a filter. This is only needed if you plan to use
580 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
581 * filter can still by instantiated with avfilter_open even if it is not
582 * registered.
583 * @param filter the filter to register
584 * @return 0 if the registration was succesfull, a negative value
585 * otherwise
586 */
587 int avfilter_register(AVFilter *filter);
588
589 /**
590 * Gets a filter definition matching the given name.
591 * @param name the filter name to find
592 * @return the filter definition, if any matching one is registered.
593 * NULL if none found.
594 */
595 AVFilter *avfilter_get_by_name(const char *name);
596
597 /**
598 * If filter is NULL, returns a pointer to the first registered filter pointer,
599 * if filter is non-NULL, returns the next pointer after filter.
600 * If the returned pointer points to NULL, the last registered filter
601 * was already reached.
602 */
603 AVFilter **av_filter_next(AVFilter **filter);
604
605 /**
606 * Creates a filter instance.
607 * @param filter the filter to create an instance of
608 * @param inst_name Name to give to the new instance. Can be NULL for none.
609 * @return Pointer to the new instance on success. NULL on failure.
610 */
611 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
612
613 /**
614 * Initializes a filter.
615 * @param filter the filter to initialize
616 * @param args A string of parameters to use when initializing the filter.
617 * The format and meaning of this string varies by filter.
618 * @param opaque Any extra non-string data needed by the filter. The meaning
619 * of this parameter varies by filter.
620 * @return zero on success
621 */
622 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
623
624 /**
625 * Destroys a filter.
626 * @param filter the filter to destroy
627 */
628 void avfilter_destroy(AVFilterContext *filter);
629
630 /**
631 * Inserts a filter in the middle of an existing link.
632 * @param link the link into which the filter should be inserted
633 * @param filt the filter to be inserted
634 * @param in the input pad on the filter to connect
635 * @param out the output pad on the filter to connect
636 * @return zero on success
637 */
638 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
639 unsigned in, unsigned out);
640
641 /**
642 * Inserts a new pad.
643 * @param idx Insertion point. Pad is inserted at the end if this point
644 * is beyond the end of the list of pads.
645 * @param count Pointer to the number of pads in the list
646 * @param padidx_off Offset within an AVFilterLink structure to the element
647 * to increment when inserting a new pad causes link
648 * numbering to change
649 * @param pads Pointer to the pointer to the beginning of the list of pads
650 * @param links Pointer to the pointer to the beginning of the list of links
651 * @param newpad The new pad to add. A copy is made when adding.
652 */
653 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
654 AVFilterPad **pads, AVFilterLink ***links,
655 AVFilterPad *newpad);
656
657 /** Inserts a new input pad for the filter. */
658 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
659 AVFilterPad *p)
660 {
661 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
662 &f->input_pads, &f->inputs, p);
663 }
664
665 /** Inserts a new output pad for the filter. */
666 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
667 AVFilterPad *p)
668 {
669 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
670 &f->output_pads, &f->outputs, p);
671 }
672
673 #endif /* AVFILTER_AVFILTER_H */