3 * copyright (c) 2007 Bobby Bingham
5 * This file is part of FFmpeg.
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.
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.
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
22 #ifndef FFMPEG_AVFILTER_H
23 #define FFMPEG_AVFILTER_H
25 #define LIBAVFILTER_VERSION 0.0.0
30 typedef struct AVFilterContext AVFilterContext;
31 typedef struct AVFilterLink AVFilterLink;
32 typedef struct AVFilterPad AVFilterPad;
34 /* TODO: look for other flags which may be useful in this structure (interlace
38 * A reference-counted picture data type used by the filter system. Filters
39 * should not store pointers to this structure directly, but instead use the
40 * AVFilterPicRef structure below.
42 typedef struct AVFilterPic
44 uint8_t *data[4]; ///< picture data for each plane
45 int linesize[4]; ///< number of bytes per line
46 enum PixelFormat format; ///< colorspace
48 unsigned refcount; ///< number of references to this image
50 /** private data to be used by a custom free function */
53 * A pointer to the function to deallocate this image if the default
54 * function is not sufficient. This could, for example, add the memory
55 * back into a memory pool to be reused later without the overhead of
56 * reallocating it from scratch.
58 void (*free)(struct AVFilterPic *pic);
62 * A reference to an AVFilterPic. Since filters can manipulate the origin of
63 * a picture to, for example, crop image without any memcpy, the picture origin
64 * and dimensions are per-reference properties. Linesize is also useful for
65 * image flipping, frame to field filters, etc, and so is also per-reference.
67 * TODO: add anything necessary for frame reordering
69 typedef struct AVFilterPicRef
71 AVFilterPic *pic; ///< the picture that this is a reference to
72 uint8_t *data[4]; ///< picture data for each plane
73 int linesize[4]; ///< number of bytes per line
74 int w; ///< image width
75 int h; ///< image height
77 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
79 AVRational pixel_aspect; ///< pixel aspect ratio
81 int perms; ///< permissions
82 #define AV_PERM_READ 0x01 ///< can read from the buffer
83 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
84 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
85 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
86 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
90 * Add a new reference to a picture.
91 * @param ref an existing reference to the picture
92 * @param pmask a bitmask containing the allowable permissions in the new
94 * @return a new reference to the picture with the same properties as the
95 * old, excluding any permissions denied by pmask
97 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
100 * Remove a reference to a picture. If this is the last reference to the
101 * picture, the picture itself is also automatically freed.
102 * @param ref reference to the picture
104 void avfilter_unref_pic(AVFilterPicRef *ref);
107 * A list of supported formats for one end of a filter link. This is used
108 * during the format negotiation process to try to pick the best format to
109 * use to minimize the number of necessary conversions. Each filter gives a
110 * list of the formats supported by each input and output pad. The list
111 * given for each pad need not be distinct - they may be references to the
112 * same list of formats, as is often the case when a filter supports multiple
113 * formats, but will always outut the same format as it is given in input.
115 * In this way, a list of possible input formats and a list of possible
116 * output formats are associated with each link. When a set of formats is
117 * negotiated over a link, the input and output lists are merged to form a
118 * new list containing only the common elements of each list. In the case
119 * that there were no common elements, a format conversion is necessary.
120 * Otherwise, the lists are merged, and all other links which reference
121 * either of the format lists involved in the merge are also affected.
123 * For example, consider the filter chain:
124 * filter (a) --> (b) filter (b) --> (c) filter
126 * where the letters in parenthesis indicate a list of formats supported on
127 * the input or output of the link. Suppose the lists are as follows:
132 * First, the first link's lists are merged, yielding:
133 * filter (a) --> (a) filter (a) --> (c) filter
135 * Notice that format list (b) now refers to the same list as filter list (a).
136 * Next, the lists for the second link are merged, yielding:
137 * filter (a) --> (a) filter (a) --> (a) filter
141 * Unfortunately, when the format lists at the two ends of a link are merged,
142 * we must ensure that all links which reference either pre-merge format list
143 * get updated as well. Therefore, we have the format list structure store a
144 * pointer to each of the pointers to itself.
146 typedef struct AVFilterFormats AVFilterFormats;
147 struct AVFilterFormats
149 unsigned format_count; ///< number of formats
150 int *formats; ///< list of formats
152 unsigned refcount; ///< number of references to this list
153 AVFilterFormats ***refs; ///< references to this list
157 * Helper function to create a list of supported formats. This is intended
158 * for use in AVFilter->query_formats().
159 * @param len the number of formats supported
160 * @param ... a list of the supported formats
161 * @return the format list, with no existing references
163 AVFilterFormats *avfilter_make_format_list(int len, ...);
166 * Returns a list of all colorspaces supported by FFmpeg.
168 AVFilterFormats *avfilter_all_colorspaces(void);
171 * Returns a format list which contains the intersection of the formats of
172 * a and b. And all the references of a and b, and a and b will be
175 * If a and b do not share any common formats, neither is modified, and NULL
178 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
181 * Adds *ref as a new reference to f.
182 * That is the pointers will point like in the ascii art below:
188 * | |* *--------->|*ref|
192 void avfilter_formats_ref(AVFilterFormats *f, AVFilterFormats **ref);
195 * Remove *ref as a reference to the format list it currently points to,
196 * deallocate that list if this was the last reference, and set *ref to NULL.
198 void avfilter_formats_unref(AVFilterFormats **ref);
204 * | f |<---------. | f |<---------.
205 * | ____ | ___|___ | ____ | ___|___
206 * | |refs| | | | | | |refs| | | | | NULL
207 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
208 * | |* * | | |_______| | |* * | | |_______| ___|___
209 * | |____| | | |____| | | | |
210 * |________| |________| |*oldref|
213 void avfilter_formats_changeref(AVFilterFormats **oldref,
214 AVFilterFormats **newref);
217 * A filter pad used for either input or output.
222 * Pad name. The name is unique among inputs and among outputs, but an
223 * input may have the same name as an output. This may be NULL if this
224 * pad has no need to ever be referenced by name.
229 * AVFilterPad type. Only video supported now, hopefully someone will
230 * add audio in the future.
235 * Minimum required permissions on incoming buffers. Any buffers with
236 * insufficient permissions will be automatically copied by the filter
237 * system to a new buffer which provides the needed access permissions.
244 * Permissions which are not accepted on incoming buffers. Any buffer
245 * which has any of these permissions set be automatically copied by the
246 * filter system to a new buffer which does not have those permissions.
247 * This can be used to easily disallow buffers with AV_PERM_REUSE.
254 * Callback called before passing the first slice of a new frame. If
255 * NULL, the filter layer will default to storing a reference to the
256 * picture inside the link structure.
258 * Input video pads only.
260 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
263 * Callback function to get a buffer. If NULL, the filter system will
264 * handle buffer requests.
266 * Input video pads only.
268 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
271 * Callback called after the slices of a frame are completely sent. If
272 * NULL, the filter layer will default to releasing the reference stored
273 * in the link structure during start_frame().
275 * Input video pads only.
277 void (*end_frame)(AVFilterLink *link);
280 * Slice drawing callback. This is where a filter receives video data
281 * and should do its processing.
283 * Input video pads only.
285 void (*draw_slice)(AVFilterLink *link, int y, int height);
288 * Frame poll callback. This returns the number of immediately available
289 * frames. It should return a positive value if the next request_frame()
290 * is guaranteed to return one frame (with no delay).
292 * Defaults to just calling the source poll_frame() method.
294 * Output video pads only.
296 int (*poll_frame)(AVFilterLink *link);
299 * Frame request callback. A call to this should result in at least one
300 * frame being output over the given link. This should return zero on
301 * success, and another value on error.
303 * Output video pads only.
305 int (*request_frame)(AVFilterLink *link);
308 * Link configuration callback.
310 * For output pads, this should set the link properties such as
311 * width/height. This should NOT set the format property - that is
312 * negotiated between filters by the filter system using the
313 * query_formats() callback before this function is called.
315 * For input pads, this should check the properties of the link, and update
316 * the filter's internal state as necessary.
318 * For both input and output filters, this should return zero on success,
319 * and another value on error.
321 int (*config_props)(AVFilterLink *link);
324 /** Default handler for start_frame() for video inputs */
325 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
326 /** Default handler for end_frame() for video inputs */
327 void avfilter_default_end_frame(AVFilterLink *link);
328 /** Default handler for config_props() for video outputs */
329 int avfilter_default_config_output_link(AVFilterLink *link);
330 /** Default handler for config_props() for video inputs */
331 int avfilter_default_config_input_link (AVFilterLink *link);
332 /** Default handler for get_video_buffer() for video inputs */
333 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
336 * A helper for query_formats() which sets all links to the same list of
337 * formats. If there are no links hooked to this filter, the list of formats is
340 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
341 /** Default handler for query_formats() */
342 int avfilter_default_query_formats(AVFilterContext *ctx);
345 * Filter definition. This defines the pads a filter contains, and all the
346 * callback functions used to interact with the filter.
350 const char *name; ///< filter name
352 int priv_size; ///< size of private data to allocate for the filter
355 * Filter initialization function. Args contains the user-supplied
356 * parameters. FIXME: maybe an AVOption-based system would be better?
357 * opaque is data provided by the code requesting creation of the filter,
358 * and is used to pass data to the filter.
360 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
363 * Filter uninitialization function. Should deallocate any memory held
364 * by the filter, release any picture references, etc. This does not need
365 * to deallocate the AVFilterContext->priv memory itself.
367 void (*uninit)(AVFilterContext *ctx);
370 * Query formats supported by the filter and its pads. Should set the
371 * in_formats for links connected to its output pads, and out_formats
372 * for links connected to its input pads.
374 * Should return zero on success.
376 int (*query_formats)(AVFilterContext *);
378 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
379 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
382 /** An instance of a filter */
383 struct AVFilterContext
385 AVClass *av_class; ///< needed for av_log()
387 AVFilter *filter; ///< the AVFilter of which this is an instance
389 char *name; ///< name of this filter instance
391 unsigned input_count; ///< number of input pads
392 AVFilterPad *input_pads; ///< array of input pads
393 AVFilterLink **inputs; ///< array of pointers to input links
395 unsigned output_count; ///< number of output pads
396 AVFilterPad *output_pads; ///< array of output pads
397 AVFilterLink **outputs; ///< array of pointers to output links
399 void *priv; ///< private data for use by the filter
403 * A link between two filters. This contains pointers to the source and
404 * destination filters between which this link exists, and the indices of
405 * the pads involved. In addition, this link also contains the parameters
406 * which have been negotiated and agreed upon between the filter, such as
407 * image dimensions, format, etc
411 AVFilterContext *src; ///< source filter
412 unsigned int srcpad; ///< index of the output pad on the source filter
414 AVFilterContext *dst; ///< dest filter
415 unsigned int dstpad; ///< index of the input pad on the dest filter
417 /** stage of the initialization of the link properties (dimensions, etc) */
419 AVLINK_UNINIT = 0, ///< not started
420 AVLINK_STARTINIT, ///< started, but incomplete
421 AVLINK_INIT ///< complete
424 int w; ///< agreed upon image width
425 int h; ///< agreed upon image height
426 enum PixelFormat format; ///< agreed upon image colorspace
429 * Lists of formats supported by the input and output filters respectively.
430 * These lists are used for negotiating the format to actually be used,
431 * which will be loaded into the format member, above, when chosen.
433 AVFilterFormats *in_formats;
434 AVFilterFormats *out_formats;
437 * The picture reference currently being sent across the link by the source
438 * filter. This is used internally by the filter system to allow
439 * automatic copying of pictures which do not have sufficient permissions
440 * for the destination. This should not be accessed directly by the
443 AVFilterPicRef *srcpic;
445 AVFilterPicRef *cur_pic;
446 AVFilterPicRef *outpic;
450 * Link two filters together.
451 * @param src the source filter
452 * @param srcpad index of the output pad on the source filter
453 * @param dst the destination filter
454 * @param dstpad index of the input pad on the destination filter
455 * @return zero on success
457 int avfilter_link(AVFilterContext *src, unsigned srcpad,
458 AVFilterContext *dst, unsigned dstpad);
461 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
462 * @param filter the filter to negotiate the properties for its inputs
463 * @return zero on successful negotiation
465 int avfilter_config_links(AVFilterContext *filter);
468 * Request a picture buffer with a specific set of permissions
469 * @param link the output link to the filter from which the picture will
471 * @param perms the required access permissions
472 * @return A reference to the picture. This must be unreferenced with
473 * avfilter_unref_pic when you are finished with it.
475 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
478 * Request an input frame from the filter at the other end of the link.
479 * @param link the input link
480 * @return zero on success
482 int avfilter_request_frame(AVFilterLink *link);
485 * Poll a frame from the filter chain.
486 * @param link the input link
487 * @return the number of imediately available frames
489 int avfilter_poll_frame(AVFilterLink *link);
492 * Notify the next filter of the start of a frame.
493 * @param link the output link the frame will be sent over
494 * @param picref A reference to the frame about to be sent. The data for this
495 * frame need only be valid once draw_slice() is called for that
496 * portion. The receiving filter will free this reference when
497 * it no longer needs it.
499 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
502 * Notify the next filter that the current frame has finished
503 * @param link the output link the frame was sent over
505 void avfilter_end_frame(AVFilterLink *link);
508 * Send a slice to the next filter.
509 * @param link the output link over which the frame is being sent
510 * @param y offset in pixels from the top of the image for this slice
511 * @param h height of this slice in pixels
513 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
515 /** Initialize the filter system. Registers all builtin filters */
516 void avfilter_register_all(void);
518 /** Uninitialize the filter system. Unregisters all filters */
519 void avfilter_uninit(void);
522 * Register a filter. This is only needed if you plan to use
523 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
524 * filter can still by instantiated with avfilter_open even if it is not
526 * @param filter the filter to register
528 void avfilter_register(AVFilter *filter);
531 * Gets a filter definition matching the given name.
532 * @param name the filter name to find
533 * @return the filter definition, if any matching one is registered.
534 * NULL if none found.
536 AVFilter *avfilter_get_by_name(const char *name);
539 * Create a filter instance.
540 * @param filter the filter to create an instance of
541 * @param inst_name Name to give to the new instance. Can be NULL for none.
542 * @return Pointer to the new instance on success. NULL on failure.
544 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
547 * Initialize a filter.
548 * @param filter the filter to initialize
549 * @param args A string of parameters to use when initializing the filter.
550 * The format and meaning of this string varies by filter.
551 * @param opaque Any extra non-string data needed by the filter. The meaning
552 * of this parameter varies by filter.
553 * @return zero on success
555 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
559 * @param filter the filter to destroy
561 void avfilter_destroy(AVFilterContext *filter);
564 * Insert a filter in the middle of an existing link.
565 * @param link the link into which the filter should be inserted
566 * @param filt the filter to be inserted
567 * @param in the input pad on the filter to connect
568 * @param out the output pad on the filter to connect
569 * @return zero on success
571 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
572 unsigned in, unsigned out);
576 * @param idx Insertion point. Pad is inserted at the end if this point
577 * is beyond the end of the list of pads.
578 * @param count Pointer to the number of pads in the list
579 * @param padidx_off Offset within an AVFilterLink structure to the element
580 * to increment when inserting a new pad causes link
581 * numbering to change
582 * @param pads Pointer to the pointer to the beginning of the list of pads
583 * @param links Pointer to the pointer to the beginning of the list of links
584 * @param newpad The new pad to add. A copy is made when adding.
586 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
587 AVFilterPad **pads, AVFilterLink ***links,
588 AVFilterPad *newpad);
590 /** insert a new input pad for the filter */
591 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
594 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
595 &f->input_pads, &f->inputs, p);
598 /** insert a new output pad for the filter */
599 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
602 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
603 &f->output_pads, &f->outputs, p);
606 #endif /* FFMPEG_AVFILTER_H */