9048aa4daa58a4704d860ae4a30ffa9958c9b18b
[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 #define LIBAVFILTER_VERSION_MAJOR 1
26 #define LIBAVFILTER_VERSION_MINOR 7
27 #define LIBAVFILTER_VERSION_MICRO 0
28
29 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
30 LIBAVFILTER_VERSION_MINOR, \
31 LIBAVFILTER_VERSION_MICRO)
32 #define LIBAVFILTER_VERSION AV_VERSION(LIBAVFILTER_VERSION_MAJOR, \
33 LIBAVFILTER_VERSION_MINOR, \
34 LIBAVFILTER_VERSION_MICRO)
35 #define LIBAVFILTER_BUILD LIBAVFILTER_VERSION_INT
36
37 #include <stddef.h>
38 #include "libavcodec/avcodec.h"
39
40 /**
41 * Returns the LIBAVFILTER_VERSION_INT constant.
42 */
43 unsigned avfilter_version(void);
44
45 typedef struct AVFilterContext AVFilterContext;
46 typedef struct AVFilterLink AVFilterLink;
47 typedef struct AVFilterPad AVFilterPad;
48
49 /* TODO: look for other flags which may be useful in this structure (interlace
50 * flags, etc)
51 */
52 /**
53 * A reference-counted picture data type used by the filter system. Filters
54 * should not store pointers to this structure directly, but instead use the
55 * AVFilterPicRef structure below.
56 */
57 typedef struct AVFilterPic
58 {
59 uint8_t *data[4]; ///< picture data for each plane
60 int linesize[4]; ///< number of bytes per line
61 enum PixelFormat format; ///< colorspace
62
63 unsigned refcount; ///< number of references to this image
64
65 /** private data to be used by a custom free function */
66 void *priv;
67 /**
68 * A pointer to the function to deallocate this image if the default
69 * function is not sufficient. This could, for example, add the memory
70 * back into a memory pool to be reused later without the overhead of
71 * reallocating it from scratch.
72 */
73 void (*free)(struct AVFilterPic *pic);
74
75 int w, h; ///< width and height of the allocated buffer
76 } AVFilterPic;
77
78 /**
79 * A reference to an AVFilterPic. Since filters can manipulate the origin of
80 * a picture to, for example, crop image without any memcpy, the picture origin
81 * and dimensions are per-reference properties. Linesize is also useful for
82 * image flipping, frame to field filters, etc, and so is also per-reference.
83 *
84 * TODO: add anything necessary for frame reordering
85 */
86 typedef struct AVFilterPicRef
87 {
88 AVFilterPic *pic; ///< the picture that this is a reference to
89 uint8_t *data[4]; ///< picture data for each plane
90 int linesize[4]; ///< number of bytes per line
91 int w; ///< image width
92 int h; ///< image height
93
94 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
95
96 AVRational pixel_aspect; ///< pixel aspect ratio
97
98 int perms; ///< permissions
99 #define AV_PERM_READ 0x01 ///< can read from the buffer
100 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
101 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
102 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
103 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
104 } AVFilterPicRef;
105
106 /**
107 * Adds a new reference to a picture.
108 * @param ref an existing reference to the picture
109 * @param pmask a bitmask containing the allowable permissions in the new
110 * reference
111 * @return a new reference to the picture with the same properties as the
112 * old, excluding any permissions denied by pmask
113 */
114 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
115
116 /**
117 * Removes a reference to a picture. If this is the last reference to the
118 * picture, the picture itself is also automatically freed.
119 * @param ref reference to the picture
120 */
121 void avfilter_unref_pic(AVFilterPicRef *ref);
122
123 /**
124 * A list of supported formats for one end of a filter link. This is used
125 * during the format negotiation process to try to pick the best format to
126 * use to minimize the number of necessary conversions. Each filter gives a
127 * list of the formats supported by each input and output pad. The list
128 * given for each pad need not be distinct - they may be references to the
129 * same list of formats, as is often the case when a filter supports multiple
130 * formats, but will always output the same format as it is given in input.
131 *
132 * In this way, a list of possible input formats and a list of possible
133 * output formats are associated with each link. When a set of formats is
134 * negotiated over a link, the input and output lists are merged to form a
135 * new list containing only the common elements of each list. In the case
136 * that there were no common elements, a format conversion is necessary.
137 * Otherwise, the lists are merged, and all other links which reference
138 * either of the format lists involved in the merge are also affected.
139 *
140 * For example, consider the filter chain:
141 * filter (a) --> (b) filter (b) --> (c) filter
142 *
143 * where the letters in parenthesis indicate a list of formats supported on
144 * the input or output of the link. Suppose the lists are as follows:
145 * (a) = {A, B}
146 * (b) = {A, B, C}
147 * (c) = {B, C}
148 *
149 * First, the first link's lists are merged, yielding:
150 * filter (a) --> (a) filter (a) --> (c) filter
151 *
152 * Notice that format list (b) now refers to the same list as filter list (a).
153 * Next, the lists for the second link are merged, yielding:
154 * filter (a) --> (a) filter (a) --> (a) filter
155 *
156 * where (a) = {B}.
157 *
158 * Unfortunately, when the format lists at the two ends of a link are merged,
159 * we must ensure that all links which reference either pre-merge format list
160 * get updated as well. Therefore, we have the format list structure store a
161 * pointer to each of the pointers to itself.
162 */
163 typedef struct AVFilterFormats AVFilterFormats;
164 struct AVFilterFormats
165 {
166 unsigned format_count; ///< number of formats
167 enum PixelFormat *formats; ///< list of pixel formats
168
169 unsigned refcount; ///< number of references to this list
170 AVFilterFormats ***refs; ///< references to this list
171 };
172
173 /**
174 * Creates a list of supported formats. This is intended for use in
175 * AVFilter->query_formats().
176 * @param pix_fmt list of pixel formats, terminated by PIX_FMT_NONE
177 * @return the format list, with no existing references
178 */
179 AVFilterFormats *avfilter_make_format_list(const enum PixelFormat *pix_fmts);
180
181 /**
182 * Returns a list of all colorspaces supported by FFmpeg.
183 */
184 AVFilterFormats *avfilter_all_colorspaces(void);
185
186 /**
187 * Returns a format list which contains the intersection of the formats of
188 * a and b. Also, all the references of a, all the references of b, and
189 * a and b themselves will be deallocated.
190 *
191 * If a and b do not share any common formats, neither is modified, and NULL
192 * is returned.
193 */
194 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
195
196 /**
197 * Adds *ref as a new reference to formats.
198 * That is the pointers will point like in the ascii art below:
199 * ________
200 * |formats |<--------.
201 * | ____ | ____|___________________
202 * | |refs| | | __|_
203 * | |* * | | | | | | AVFilterLink
204 * | |* *--------->|*ref|
205 * | |____| | | |____|
206 * |________| |________________________
207 */
208 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
209
210 /**
211 * Removes *ref as a reference to the format list it currently points to,
212 * deallocates that list if this was the last reference, and sets *ref to NULL.
213 *
214 * Before After
215 * ________ ________ NULL
216 * |formats |<--------. |formats | ^
217 * | ____ | ____|________________ | ____ | ____|________________
218 * | |refs| | | __|_ | |refs| | | __|_
219 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
220 * | |* *--------->|*ref| | |* | | | |*ref|
221 * | |____| | | |____| | |____| | | |____|
222 * |________| |_____________________ |________| |_____________________
223 */
224 void avfilter_formats_unref(AVFilterFormats **ref);
225
226 /**
227 *
228 * Before After
229 * ________ ________
230 * |formats |<---------. |formats |<---------.
231 * | ____ | ___|___ | ____ | ___|___
232 * | |refs| | | | | | |refs| | | | | NULL
233 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
234 * | |* * | | |_______| | |* * | | |_______| ___|___
235 * | |____| | | |____| | | | |
236 * |________| |________| |*oldref|
237 * |_______|
238 */
239 void avfilter_formats_changeref(AVFilterFormats **oldref,
240 AVFilterFormats **newref);
241
242 /**
243 * A filter pad used for either input or output.
244 */
245 struct AVFilterPad
246 {
247 /**
248 * Pad name. The name is unique among inputs and among outputs, but an
249 * input may have the same name as an output. This may be NULL if this
250 * pad has no need to ever be referenced by name.
251 */
252 const char *name;
253
254 /**
255 * AVFilterPad type. Only video supported now, hopefully someone will
256 * add audio in the future.
257 */
258 enum CodecType type;
259
260 /**
261 * Minimum required permissions on incoming buffers. Any buffer with
262 * insufficient permissions will be automatically copied by the filter
263 * system to a new buffer which provides the needed access permissions.
264 *
265 * Input pads only.
266 */
267 int min_perms;
268
269 /**
270 * Permissions which are not accepted on incoming buffers. Any buffer
271 * which has any of these permissions set will be automatically copied
272 * by the filter system to a new buffer which does not have those
273 * permissions. This can be used to easily disallow buffers with
274 * AV_PERM_REUSE.
275 *
276 * Input pads only.
277 */
278 int rej_perms;
279
280 /**
281 * Callback called before passing the first slice of a new frame. If
282 * NULL, the filter layer will default to storing a reference to the
283 * picture inside the link structure.
284 *
285 * Input video pads only.
286 */
287 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
288
289 /**
290 * Callback function to get a buffer. If NULL, the filter system will
291 * use avfilter_default_get_video_buffer().
292 *
293 * Input video pads only.
294 */
295 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
296
297 /**
298 * Callback called after the slices of a frame are completely sent. If
299 * NULL, the filter layer will default to releasing the reference stored
300 * in the link structure during start_frame().
301 *
302 * Input video pads only.
303 */
304 void (*end_frame)(AVFilterLink *link);
305
306 /**
307 * Slice drawing callback. This is where a filter receives video data
308 * and should do its processing.
309 *
310 * Input video pads only.
311 */
312 void (*draw_slice)(AVFilterLink *link, int y, int height);
313
314 /**
315 * Frame poll callback. This returns the number of immediately available
316 * frames. It should return a positive value if the next request_frame()
317 * is guaranteed to return one frame (with no delay).
318 *
319 * Defaults to just calling the source poll_frame() method.
320 *
321 * Output video pads only.
322 */
323 int (*poll_frame)(AVFilterLink *link);
324
325 /**
326 * Frame request callback. A call to this should result in at least one
327 * frame being output over the given link. This should return zero on
328 * success, and another value on error.
329 *
330 * Output video pads only.
331 */
332 int (*request_frame)(AVFilterLink *link);
333
334 /**
335 * Link configuration callback.
336 *
337 * For output pads, this should set the link properties such as
338 * width/height. This should NOT set the format property - that is
339 * negotiated between filters by the filter system using the
340 * query_formats() callback before this function is called.
341 *
342 * For input pads, this should check the properties of the link, and update
343 * the filter's internal state as necessary.
344 *
345 * For both input and output filters, this should return zero on success,
346 * and another value on error.
347 */
348 int (*config_props)(AVFilterLink *link);
349 };
350
351 /** default handler for start_frame() for video inputs */
352 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
353 /** default handler for draw_slice() for video inputs */
354 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h);
355 /** default handler for end_frame() for video inputs */
356 void avfilter_default_end_frame(AVFilterLink *link);
357 /** default handler for config_props() for video outputs */
358 int avfilter_default_config_output_link(AVFilterLink *link);
359 /** default handler for config_props() for video inputs */
360 int avfilter_default_config_input_link (AVFilterLink *link);
361 /** default handler for get_video_buffer() for video inputs */
362 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
363 int perms, int w, int h);
364 /**
365 * A helper for query_formats() which sets all links to the same list of
366 * formats. If there are no links hooked to this filter, the list of formats is
367 * freed.
368 */
369 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
370 /** Default handler for query_formats() */
371 int avfilter_default_query_formats(AVFilterContext *ctx);
372
373 /**
374 * Filter definition. This defines the pads a filter contains, and all the
375 * callback functions used to interact with the filter.
376 */
377 typedef struct AVFilter
378 {
379 const char *name; ///< filter name
380
381 int priv_size; ///< size of private data to allocate for the filter
382
383 /**
384 * Filter initialization function. Args contains the user-supplied
385 * parameters. FIXME: maybe an AVOption-based system would be better?
386 * opaque is data provided by the code requesting creation of the filter,
387 * and is used to pass data to the filter.
388 */
389 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
390
391 /**
392 * Filter uninitialization function. Should deallocate any memory held
393 * by the filter, release any picture references, etc. This does not need
394 * to deallocate the AVFilterContext->priv memory itself.
395 */
396 void (*uninit)(AVFilterContext *ctx);
397
398 /**
399 * Query formats supported by the filter and its pads. Should set the
400 * in_formats for links connected to its output pads, and out_formats
401 * for links connected to its input pads.
402 *
403 * Should return zero on success.
404 */
405 int (*query_formats)(AVFilterContext *);
406
407 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
408 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
409
410 /**
411 * A description for the filter. You should use the
412 * NULL_IF_CONFIG_SMALL() macro to define it.
413 */
414 const char *description;
415
416 /**
417 * The next registered filter, NULL if this is the last one.
418 */
419 struct AVFilter *next;
420 } AVFilter;
421
422 /** An instance of a filter */
423 struct AVFilterContext
424 {
425 const AVClass *av_class; ///< needed for av_log()
426
427 AVFilter *filter; ///< the AVFilter of which this is an instance
428
429 char *name; ///< name of this filter instance
430
431 unsigned input_count; ///< number of input pads
432 AVFilterPad *input_pads; ///< array of input pads
433 AVFilterLink **inputs; ///< array of pointers to input links
434
435 unsigned output_count; ///< number of output pads
436 AVFilterPad *output_pads; ///< array of output pads
437 AVFilterLink **outputs; ///< array of pointers to output links
438
439 void *priv; ///< private data for use by the filter
440 };
441
442 /**
443 * A link between two filters. This contains pointers to the source and
444 * destination filters between which this link exists, and the indexes of
445 * the pads involved. In addition, this link also contains the parameters
446 * which have been negotiated and agreed upon between the filter, such as
447 * image dimensions, format, etc.
448 */
449 struct AVFilterLink
450 {
451 AVFilterContext *src; ///< source filter
452 unsigned int srcpad; ///< index of the output pad on the source filter
453
454 AVFilterContext *dst; ///< dest filter
455 unsigned int dstpad; ///< index of the input pad on the dest filter
456
457 /** stage of the initialization of the link properties (dimensions, etc) */
458 enum {
459 AVLINK_UNINIT = 0, ///< not started
460 AVLINK_STARTINIT, ///< started, but incomplete
461 AVLINK_INIT ///< complete
462 } init_state;
463
464 int w; ///< agreed upon image width
465 int h; ///< agreed upon image height
466 enum PixelFormat format; ///< agreed upon image colorspace
467
468 /**
469 * Lists of formats supported by the input and output filters respectively.
470 * These lists are used for negotiating the format to actually be used,
471 * which will be loaded into the format member, above, when chosen.
472 */
473 AVFilterFormats *in_formats;
474 AVFilterFormats *out_formats;
475
476 /**
477 * The picture reference currently being sent across the link by the source
478 * filter. This is used internally by the filter system to allow
479 * automatic copying of pictures which do not have sufficient permissions
480 * for the destination. This should not be accessed directly by the
481 * filters.
482 */
483 AVFilterPicRef *srcpic;
484
485 AVFilterPicRef *cur_pic;
486 AVFilterPicRef *outpic;
487 };
488
489 /**
490 * Links two filters together.
491 * @param src the source filter
492 * @param srcpad index of the output pad on the source filter
493 * @param dst the destination filter
494 * @param dstpad index of the input pad on the destination filter
495 * @return zero on success
496 */
497 int avfilter_link(AVFilterContext *src, unsigned srcpad,
498 AVFilterContext *dst, unsigned dstpad);
499
500 /**
501 * Negotiates the colorspace, dimensions, etc of all inputs to a filter.
502 * @param filter the filter to negotiate the properties for its inputs
503 * @return zero on successful negotiation
504 */
505 int avfilter_config_links(AVFilterContext *filter);
506
507 /**
508 * Requests a picture buffer with a specific set of permissions.
509 * @param link the output link to the filter from which the picture will
510 * be requested
511 * @param perms the required access permissions
512 * @param w the minimum width of the buffer to allocate
513 * @param h the minimum height of the buffer to allocate
514 * @return A reference to the picture. This must be unreferenced with
515 * avfilter_unref_pic when you are finished with it.
516 */
517 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
518 int w, int h);
519
520 /**
521 * Requests an input frame from the filter at the other end of the link.
522 * @param link the input link
523 * @return zero on success
524 */
525 int avfilter_request_frame(AVFilterLink *link);
526
527 /**
528 * Polls a frame from the filter chain.
529 * @param link the input link
530 * @return the number of immediately available frames, a negative
531 * number in case of error
532 */
533 int avfilter_poll_frame(AVFilterLink *link);
534
535 /**
536 * Notifies the next filter of the start of a frame.
537 * @param link the output link the frame will be sent over
538 * @param picref A reference to the frame about to be sent. The data for this
539 * frame need only be valid once draw_slice() is called for that
540 * portion. The receiving filter will free this reference when
541 * it no longer needs it.
542 */
543 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
544
545 /**
546 * Notifies the next filter that the current frame has finished.
547 * @param link the output link the frame was sent over
548 */
549 void avfilter_end_frame(AVFilterLink *link);
550
551 /**
552 * Sends a slice to the next filter.
553 * @param link the output link over which the frame is being sent
554 * @param y offset in pixels from the top of the image for this slice
555 * @param h height of this slice in pixels
556 */
557 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
558
559 /** Initializes the filter system. Registers all builtin filters. */
560 void avfilter_register_all(void);
561
562 /** Uninitializes the filter system. Unregisters all filters. */
563 void avfilter_uninit(void);
564
565 /**
566 * Registers a filter. This is only needed if you plan to use
567 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
568 * filter can still by instantiated with avfilter_open even if it is not
569 * registered.
570 * @param filter the filter to register
571 */
572 void avfilter_register(AVFilter *filter);
573
574 /**
575 * Gets a filter definition matching the given name.
576 * @param name the filter name to find
577 * @return the filter definition, if any matching one is registered.
578 * NULL if none found.
579 */
580 AVFilter *avfilter_get_by_name(const char *name);
581
582 /**
583 * Creates a filter instance.
584 * @param filter the filter to create an instance of
585 * @param inst_name Name to give to the new instance. Can be NULL for none.
586 * @return Pointer to the new instance on success. NULL on failure.
587 */
588 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
589
590 /**
591 * Initializes a filter.
592 * @param filter the filter to initialize
593 * @param args A string of parameters to use when initializing the filter.
594 * The format and meaning of this string varies by filter.
595 * @param opaque Any extra non-string data needed by the filter. The meaning
596 * of this parameter varies by filter.
597 * @return zero on success
598 */
599 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
600
601 /**
602 * Destroys a filter.
603 * @param filter the filter to destroy
604 */
605 void avfilter_destroy(AVFilterContext *filter);
606
607 /**
608 * Inserts a filter in the middle of an existing link.
609 * @param link the link into which the filter should be inserted
610 * @param filt the filter to be inserted
611 * @param in the input pad on the filter to connect
612 * @param out the output pad on the filter to connect
613 * @return zero on success
614 */
615 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
616 unsigned in, unsigned out);
617
618 /**
619 * Inserts a new pad.
620 * @param idx Insertion point. Pad is inserted at the end if this point
621 * is beyond the end of the list of pads.
622 * @param count Pointer to the number of pads in the list
623 * @param padidx_off Offset within an AVFilterLink structure to the element
624 * to increment when inserting a new pad causes link
625 * numbering to change
626 * @param pads Pointer to the pointer to the beginning of the list of pads
627 * @param links Pointer to the pointer to the beginning of the list of links
628 * @param newpad The new pad to add. A copy is made when adding.
629 */
630 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
631 AVFilterPad **pads, AVFilterLink ***links,
632 AVFilterPad *newpad);
633
634 /** Inserts a new input pad for the filter. */
635 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
636 AVFilterPad *p)
637 {
638 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
639 &f->input_pads, &f->inputs, p);
640 }
641
642 /** Inserts a new output pad for the filter. */
643 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
644 AVFilterPad *p)
645 {
646 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
647 &f->output_pads, &f->outputs, p);
648 }
649
650 #endif /* AVFILTER_AVFILTER_H */