Use CodecType for pad type
[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 FFMPEG_AVFILTER_H
23 #define FFMPEG_AVFILTER_H
24
25 #include <stddef.h>
26 #include "avcodec.h"
27
28 typedef struct AVFilterContext AVFilterContext;
29 typedef struct AVFilterLink AVFilterLink;
30 typedef 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 */
40 typedef struct AVFilterPic
41 {
42 uint8_t *data[4]; ///< picture data for each plane
43 int linesize[4]; ///< number of bytes per line
44 enum PixelFormat format; ///< colorspace
45
46 unsigned refcount; ///< number of references to this image
47
48 /** private data to be used by a custom free function */
49 void *priv;
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 */
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
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.
64 *
65 * TODO: add anything necessary for frame reordering
66 */
67 typedef struct AVFilterPicRef
68 {
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
74
75 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
76
77 AVRational pixel_aspect; ///< pixel aspect ratio
78
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
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
85 } AVFilterPicRef;
86
87 /**
88 * Add a new reference to a picture.
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
94 */
95 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
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 */
102 void avfilter_unref_pic(AVFilterPicRef *ref);
103
104 /**
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 */
144 typedef struct AVFilterFormats AVFilterFormats;
145 struct 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 */
161 AVFilterFormats *avfilter_make_format_list(int len, ...);
162
163 /**
164 * Returns a list of all colorspaces supported by FFmpeg.
165 */
166 AVFilterFormats *avfilter_all_colorspaces(void);
167
168 /**
169 * If a and b share at least one common format, they are merged into a new
170 * format list which is returned. All the references to a and b are updated
171 * to point to this new list, and a and b are deallocated.
172 *
173 * If a and b do not share any common formats, neither is modified, and NULL
174 * is returned.
175 */
176 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
177
178 /** Adds *ref as a new reference to f */
179 void avfilter_formats_ref(AVFilterFormats *f, AVFilterFormats **ref);
180
181 /**
182 * Remove *ref as a reference to the format list it currently points to,
183 * deallocate that list if this was the last reference, and set *ref to NULL.
184 */
185 void avfilter_formats_unref(AVFilterFormats **ref);
186
187 /**
188 * A filter pad used for either input or output.
189 */
190 struct AVFilterPad
191 {
192 /**
193 * Pad name. The name is unique among inputs and among outputs, but an
194 * input may have the same name as an output. This may be NULL if this
195 * pad has no need to ever be referenced by name.
196 */
197 const char *name;
198
199 /**
200 * AVFilterPad type. Only video supported now, hopefully someone will
201 * add audio in the future.
202 */
203 enum CodecType type;
204
205 /**
206 * Minimum required permissions on incoming buffers. Any buffers with
207 * insufficient permissions will be automatically copied by the filter
208 * system to a new buffer which provides the needed access permissions.
209 *
210 * Input pads only.
211 */
212 int min_perms;
213
214 /**
215 * Permissions which are not accepted on incoming buffers. Any buffer
216 * which has any of these permissions set be automatically copied by the
217 * filter system to a new buffer which does not have those permissions.
218 * This can be used to easily disallow buffers with AV_PERM_REUSE.
219 *
220 * Input pads only.
221 */
222 int rej_perms;
223
224 /**
225 * Callback called before passing the first slice of a new frame. If
226 * NULL, the filter layer will default to storing a reference to the
227 * picture inside the link structure.
228 *
229 * Input video pads only.
230 */
231 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
232
233 /**
234 * Callback function to get a buffer. If NULL, the filter system will
235 * handle buffer requests.
236 *
237 * Input video pads only.
238 */
239 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
240
241 /**
242 * Callback called after the slices of a frame are completely sent. If
243 * NULL, the filter layer will default to releasing the reference stored
244 * in the link structure during start_frame().
245 *
246 * Input video pads only.
247 */
248 void (*end_frame)(AVFilterLink *link);
249
250 /**
251 * Slice drawing callback. This is where a filter receives video data
252 * and should do its processing.
253 *
254 * Input video pads only.
255 */
256 void (*draw_slice)(AVFilterLink *link, int y, int height);
257
258 /**
259 * Frame poll callback. This returns the number of immediately available
260 * frames. It should return a positive value if the next request_frame()
261 * is guaranteed to return one frame (with no delay).
262 *
263 * Defaults to just calling the source poll_frame() method.
264 *
265 * Output video pads only.
266 */
267 int (*poll_frame)(AVFilterLink *link);
268
269 /**
270 * Frame request callback. A call to this should result in at least one
271 * frame being output over the given link. This should return zero on
272 * success, and another value on error.
273 *
274 * Output video pads only.
275 */
276 int (*request_frame)(AVFilterLink *link);
277
278 /**
279 * Link configuration callback.
280 *
281 * For output pads, this should set the link properties such as
282 * width/height. This should NOT set the format property - that is
283 * negotiated between filters by the filter system using the
284 * query_formats() callback before this function is called.
285 *
286 * For input pads, this should check the properties of the link, and update
287 * the filter's internal state as necessary.
288 *
289 * For both input and output filters, this should return zero on success,
290 * and another value on error.
291 */
292 int (*config_props)(AVFilterLink *link);
293 };
294
295 /** Default handler for start_frame() for video inputs */
296 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
297 /** Default handler for end_frame() for video inputs */
298 void avfilter_default_end_frame(AVFilterLink *link);
299 /** Default handler for config_props() for video outputs */
300 int avfilter_default_config_output_link(AVFilterLink *link);
301 /** Default handler for config_props() for video inputs */
302 int avfilter_default_config_input_link (AVFilterLink *link);
303 /** Default handler for get_video_buffer() for video inputs */
304 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
305 int perms);
306 /**
307 * A helper for query_formats() which sets all links to the same list of
308 * formats. If there are no links hooked to this filter, the list of formats is
309 * freed.
310 */
311 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
312 /** Default handler for query_formats() */
313 int avfilter_default_query_formats(AVFilterContext *ctx);
314
315 void avfilter_formats_changeref(AVFilterFormats **oldref,
316 AVFilterFormats **newref);
317
318 /**
319 * Filter definition. This defines the pads a filter contains, and all the
320 * callback functions used to interact with the filter.
321 */
322 typedef struct
323 {
324 const char *name; ///< filter name
325 const char *author; ///< filter author
326
327 int priv_size; ///< size of private data to allocate for the filter
328
329 /**
330 * Filter initialization function. Args contains the user-supplied
331 * parameters. FIXME: maybe an AVOption-based system would be better?
332 * opaque is data provided by the code requesting creation of the filter,
333 * and is used to pass data to the filter.
334 */
335 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
336
337 /**
338 * Filter uninitialization function. Should deallocate any memory held
339 * by the filter, release any picture references, etc. This does not need
340 * to deallocate the AVFilterContext->priv memory itself.
341 */
342 void (*uninit)(AVFilterContext *ctx);
343
344 /**
345 * Query formats supported by the filter and its pads. Should set the
346 * in_formats for links connected to its output pads, and out_formats
347 * for links connected to its input pads.
348 *
349 * Should return zero on success.
350 */
351 int (*query_formats)(AVFilterContext *);
352
353 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
354 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
355 } AVFilter;
356
357 /** An instance of a filter */
358 struct AVFilterContext
359 {
360 AVClass *av_class; ///< needed for av_log()
361
362 AVFilter *filter; ///< the AVFilter of which this is an instance
363
364 char *name; ///< name of this filter instance
365
366 unsigned input_count; ///< number of input pads
367 AVFilterPad *input_pads; ///< array of input pads
368 AVFilterLink **inputs; ///< array of pointers to input links
369
370 unsigned output_count; ///< number of output pads
371 AVFilterPad *output_pads; ///< array of output pads
372 AVFilterLink **outputs; ///< array of pointers to output links
373
374 void *priv; ///< private data for use by the filter
375 };
376
377 /**
378 * A link between two filters. This contains pointers to the source and
379 * destination filters between which this link exists, and the indices of
380 * the pads involved. In addition, this link also contains the parameters
381 * which have been negotiated and agreed upon between the filter, such as
382 * image dimensions, format, etc
383 */
384 struct AVFilterLink
385 {
386 AVFilterContext *src; ///< source filter
387 unsigned int srcpad; ///< index of the output pad on the source filter
388
389 AVFilterContext *dst; ///< dest filter
390 unsigned int dstpad; ///< index of the input pad on the dest filter
391
392 /** stage of the initialization of the link properties (dimensions, etc) */
393 enum {
394 AVLINK_UNINIT = 0, ///< not started
395 AVLINK_STARTINIT, ///< started, but incomplete
396 AVLINK_INIT ///< complete
397 } init_state;
398
399 int w; ///< agreed upon image width
400 int h; ///< agreed upon image height
401 enum PixelFormat format; ///< agreed upon image colorspace
402
403 /**
404 * Lists of formats supported by the input and output filters respectively.
405 * These lists are used for negotiating the format to actually be used,
406 * which will be loaded into the format member, above, when chosen.
407 */
408 AVFilterFormats *in_formats;
409 AVFilterFormats *out_formats;
410
411 /**
412 * The picture reference currently being sent across the link by the source
413 * filter. This is used internally by the filter system to allow
414 * automatic copying of pictures which do not have sufficient permissions
415 * for the destination. This should not be accessed directly by the
416 * filters.
417 */
418 AVFilterPicRef *srcpic;
419
420 AVFilterPicRef *cur_pic;
421 AVFilterPicRef *outpic;
422 };
423
424 /**
425 * Link two filters together.
426 * @param src the source filter
427 * @param srcpad index of the output pad on the source filter
428 * @param dst the destination filter
429 * @param dstpad index of the input pad on the destination filter
430 * @return zero on success
431 */
432 int avfilter_link(AVFilterContext *src, unsigned srcpad,
433 AVFilterContext *dst, unsigned dstpad);
434
435 /**
436 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
437 * @param filter the filter to negotiate the properties for its inputs
438 * @return zero on successful negotiation
439 */
440 int avfilter_config_links(AVFilterContext *filter);
441
442 /**
443 * Request a picture buffer with a specific set of permissions
444 * @param link the output link to the filter from which the picture will
445 * be requested
446 * @param perms the required access permissions
447 * @return A reference to the picture. This must be unreferenced with
448 * avfilter_unref_pic when you are finished with it.
449 */
450 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
451
452 /**
453 * Request an input frame from the filter at the other end of the link.
454 * @param link the input link
455 * @return zero on success
456 */
457 int avfilter_request_frame(AVFilterLink *link);
458
459 /**
460 * Poll a frame from the filter chain.
461 * @param link the input link
462 * @return the number of imediately available frames
463 */
464 int avfilter_poll_frame(AVFilterLink *link);
465
466 /**
467 * Notify the next filter of the start of a frame.
468 * @param link the output link the frame will be sent over
469 * @param picref A reference to the frame about to be sent. The data for this
470 * frame need only be valid once draw_slice() is called for that
471 * portion. The receiving filter will free this reference when
472 * it no longer needs it.
473 */
474 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
475
476 /**
477 * Notify the next filter that the current frame has finished
478 * @param link the output link the frame was sent over
479 */
480 void avfilter_end_frame(AVFilterLink *link);
481
482 /**
483 * Send a slice to the next filter.
484 * @param link the output link over which the frame is being sent
485 * @param y offset in pixels from the top of the image for this slice
486 * @param h height of this slice in pixels
487 */
488 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
489
490 /** Initialize the filter system. Registers all builtin filters */
491 void avfilter_init(void);
492
493 /** Uninitialize the filter system. Unregisters all filters */
494 void avfilter_uninit(void);
495
496 /**
497 * Register a filter. This is only needed if you plan to use
498 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
499 * filter can still by instantiated with avfilter_open even if it is not
500 * registered.
501 * @param filter the filter to register
502 */
503 void avfilter_register(AVFilter *filter);
504
505 /**
506 * Gets a filter definition matching the given name.
507 * @param name the filter name to find
508 * @return the filter definition, if any matching one is registered.
509 * NULL if none found.
510 */
511 AVFilter *avfilter_get_by_name(const char *name);
512
513 /**
514 * Create a filter instance.
515 * @param filter the filter to create an instance of
516 * @param inst_name Name to give to the new instance. Can be NULL for none.
517 * @return Pointer to the new instance on success. NULL on failure.
518 */
519 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
520
521 /**
522 * Initialize a filter.
523 * @param filter the filter to initialize
524 * @param args A string of parameters to use when initializing the filter.
525 * The format and meaning of this string varies by filter.
526 * @param opaque Any extra non-string data needed by the filter. The meaning
527 * of this parameter varies by filter.
528 * @return zero on success
529 */
530 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
531
532 /**
533 * Destroy a filter.
534 * @param filter the filter to destroy
535 */
536 void avfilter_destroy(AVFilterContext *filter);
537
538 /**
539 * Insert a filter in the middle of an existing link.
540 * @param link the link into which the filter should be inserted
541 * @param filt the filter to be inserted
542 * @param in the input pad on the filter to connect
543 * @param out the output pad on the filter to connect
544 * @return zero on success
545 */
546 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
547 unsigned in, unsigned out);
548
549 /**
550 * Insert a new pad.
551 * @param idx Insertion point. Pad is inserted at the end if this point
552 * is beyond the end of the list of pads.
553 * @param count Pointer to the number of pads in the list
554 * @param padidx_off Offset within an AVFilterLink structure to the element
555 * to increment when inserting a new pad causes link
556 * numbering to change
557 * @param pads Pointer to the pointer to the beginning of the list of pads
558 * @param links Pointer to the pointer to the beginning of the list of links
559 * @param newpad The new pad to add. A copy is made when adding.
560 */
561 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
562 AVFilterPad **pads, AVFilterLink ***links,
563 AVFilterPad *newpad);
564
565 /** insert a new input pad for the filter */
566 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
567 AVFilterPad *p)
568 {
569 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
570 &f->input_pads, &f->inputs, p);
571 }
572
573 /** insert a new output pad for the filter */
574 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
575 AVFilterPad *p)
576 {
577 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
578 &f->output_pads, &f->outputs, p);
579 }
580
581 #endif /* FFMPEG_AVFILTER_H */