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_MAJOR 0
26 #define LIBAVFILTER_VERSION_MINOR 0
27 #define LIBAVFILTER_VERSION_MICRO 0
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
40 typedef struct AVFilterContext AVFilterContext;
41 typedef struct AVFilterLink AVFilterLink;
42 typedef struct AVFilterPad AVFilterPad;
44 /* TODO: look for other flags which may be useful in this structure (interlace
48 * A reference-counted picture data type used by the filter system. Filters
49 * should not store pointers to this structure directly, but instead use the
50 * AVFilterPicRef structure below.
52 typedef struct AVFilterPic
54 uint8_t *data[4]; ///< picture data for each plane
55 int linesize[4]; ///< number of bytes per line
56 enum PixelFormat format; ///< colorspace
58 unsigned refcount; ///< number of references to this image
60 /** private data to be used by a custom free function */
63 * A pointer to the function to deallocate this image if the default
64 * function is not sufficient. This could, for example, add the memory
65 * back into a memory pool to be reused later without the overhead of
66 * reallocating it from scratch.
68 void (*free)(struct AVFilterPic *pic);
72 * A reference to an AVFilterPic. Since filters can manipulate the origin of
73 * a picture to, for example, crop image without any memcpy, the picture origin
74 * and dimensions are per-reference properties. Linesize is also useful for
75 * image flipping, frame to field filters, etc, and so is also per-reference.
77 * TODO: add anything necessary for frame reordering
79 typedef struct AVFilterPicRef
81 AVFilterPic *pic; ///< the picture that this is a reference to
82 uint8_t *data[4]; ///< picture data for each plane
83 int linesize[4]; ///< number of bytes per line
84 int w; ///< image width
85 int h; ///< image height
87 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
89 AVRational pixel_aspect; ///< pixel aspect ratio
91 int perms; ///< permissions
92 #define AV_PERM_READ 0x01 ///< can read from the buffer
93 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
94 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
95 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
96 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
100 * Add a new reference to a picture.
101 * @param ref an existing reference to the picture
102 * @param pmask a bitmask containing the allowable permissions in the new
104 * @return a new reference to the picture with the same properties as the
105 * old, excluding any permissions denied by pmask
107 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
110 * Remove a reference to a picture. If this is the last reference to the
111 * picture, the picture itself is also automatically freed.
112 * @param ref reference to the picture
114 void avfilter_unref_pic(AVFilterPicRef *ref);
117 * A list of supported formats for one end of a filter link. This is used
118 * during the format negotiation process to try to pick the best format to
119 * use to minimize the number of necessary conversions. Each filter gives a
120 * list of the formats supported by each input and output pad. The list
121 * given for each pad need not be distinct - they may be references to the
122 * same list of formats, as is often the case when a filter supports multiple
123 * formats, but will always outut the same format as it is given in input.
125 * In this way, a list of possible input formats and a list of possible
126 * output formats are associated with each link. When a set of formats is
127 * negotiated over a link, the input and output lists are merged to form a
128 * new list containing only the common elements of each list. In the case
129 * that there were no common elements, a format conversion is necessary.
130 * Otherwise, the lists are merged, and all other links which reference
131 * either of the format lists involved in the merge are also affected.
133 * For example, consider the filter chain:
134 * filter (a) --> (b) filter (b) --> (c) filter
136 * where the letters in parenthesis indicate a list of formats supported on
137 * the input or output of the link. Suppose the lists are as follows:
142 * First, the first link's lists are merged, yielding:
143 * filter (a) --> (a) filter (a) --> (c) filter
145 * Notice that format list (b) now refers to the same list as filter list (a).
146 * Next, the lists for the second link are merged, yielding:
147 * filter (a) --> (a) filter (a) --> (a) filter
151 * Unfortunately, when the format lists at the two ends of a link are merged,
152 * we must ensure that all links which reference either pre-merge format list
153 * get updated as well. Therefore, we have the format list structure store a
154 * pointer to each of the pointers to itself.
156 typedef struct AVFilterFormats AVFilterFormats;
157 struct AVFilterFormats
159 unsigned format_count; ///< number of formats
160 int *formats; ///< list of formats
162 unsigned refcount; ///< number of references to this list
163 AVFilterFormats ***refs; ///< references to this list
167 * Helper function to create a list of supported formats. This is intended
168 * for use in AVFilter->query_formats().
169 * @param len the number of formats supported
170 * @param ... a list of the supported formats
171 * @return the format list, with no existing references
173 AVFilterFormats *avfilter_make_format_list(int len, ...);
176 * Returns a list of all colorspaces supported by FFmpeg.
178 AVFilterFormats *avfilter_all_colorspaces(void);
181 * Returns a format list which contains the intersection of the formats of
182 * a and b. And all the references of a and b, and a and b will be
185 * If a and b do not share any common formats, neither is modified, and NULL
188 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
191 * Adds *ref as a new reference to f.
192 * That is the pointers will point like in the ascii art below:
198 * | |* *--------->|*ref|
202 void avfilter_formats_ref(AVFilterFormats *f, AVFilterFormats **ref);
205 * Remove *ref as a reference to the format list it currently points to,
206 * deallocate that list if this was the last reference, and set *ref to NULL.
208 void avfilter_formats_unref(AVFilterFormats **ref);
214 * | f |<---------. | f |<---------.
215 * | ____ | ___|___ | ____ | ___|___
216 * | |refs| | | | | | |refs| | | | | NULL
217 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
218 * | |* * | | |_______| | |* * | | |_______| ___|___
219 * | |____| | | |____| | | | |
220 * |________| |________| |*oldref|
223 void avfilter_formats_changeref(AVFilterFormats **oldref,
224 AVFilterFormats **newref);
227 * A filter pad used for either input or output.
232 * Pad name. The name is unique among inputs and among outputs, but an
233 * input may have the same name as an output. This may be NULL if this
234 * pad has no need to ever be referenced by name.
239 * AVFilterPad type. Only video supported now, hopefully someone will
240 * add audio in the future.
245 * Minimum required permissions on incoming buffers. Any buffers with
246 * insufficient permissions will be automatically copied by the filter
247 * system to a new buffer which provides the needed access permissions.
254 * Permissions which are not accepted on incoming buffers. Any buffer
255 * which has any of these permissions set be automatically copied by the
256 * filter system to a new buffer which does not have those permissions.
257 * This can be used to easily disallow buffers with AV_PERM_REUSE.
264 * Callback called before passing the first slice of a new frame. If
265 * NULL, the filter layer will default to storing a reference to the
266 * picture inside the link structure.
268 * Input video pads only.
270 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
273 * Callback function to get a buffer. If NULL, the filter system will
274 * handle buffer requests.
276 * Input video pads only.
278 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
281 * Callback called after the slices of a frame are completely sent. If
282 * NULL, the filter layer will default to releasing the reference stored
283 * in the link structure during start_frame().
285 * Input video pads only.
287 void (*end_frame)(AVFilterLink *link);
290 * Slice drawing callback. This is where a filter receives video data
291 * and should do its processing.
293 * Input video pads only.
295 void (*draw_slice)(AVFilterLink *link, int y, int height);
298 * Frame poll callback. This returns the number of immediately available
299 * frames. It should return a positive value if the next request_frame()
300 * is guaranteed to return one frame (with no delay).
302 * Defaults to just calling the source poll_frame() method.
304 * Output video pads only.
306 int (*poll_frame)(AVFilterLink *link);
309 * Frame request callback. A call to this should result in at least one
310 * frame being output over the given link. This should return zero on
311 * success, and another value on error.
313 * Output video pads only.
315 int (*request_frame)(AVFilterLink *link);
318 * Link configuration callback.
320 * For output pads, this should set the link properties such as
321 * width/height. This should NOT set the format property - that is
322 * negotiated between filters by the filter system using the
323 * query_formats() callback before this function is called.
325 * For input pads, this should check the properties of the link, and update
326 * the filter's internal state as necessary.
328 * For both input and output filters, this should return zero on success,
329 * and another value on error.
331 int (*config_props)(AVFilterLink *link);
334 /** Default handler for start_frame() for video inputs */
335 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
336 /** Default handler for end_frame() for video inputs */
337 void avfilter_default_end_frame(AVFilterLink *link);
338 /** Default handler for config_props() for video outputs */
339 int avfilter_default_config_output_link(AVFilterLink *link);
340 /** Default handler for config_props() for video inputs */
341 int avfilter_default_config_input_link (AVFilterLink *link);
342 /** Default handler for get_video_buffer() for video inputs */
343 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
346 * A helper for query_formats() which sets all links to the same list of
347 * formats. If there are no links hooked to this filter, the list of formats is
350 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
351 /** Default handler for query_formats() */
352 int avfilter_default_query_formats(AVFilterContext *ctx);
355 * Filter definition. This defines the pads a filter contains, and all the
356 * callback functions used to interact with the filter.
360 const char *name; ///< filter name
362 int priv_size; ///< size of private data to allocate for the filter
365 * Filter initialization function. Args contains the user-supplied
366 * parameters. FIXME: maybe an AVOption-based system would be better?
367 * opaque is data provided by the code requesting creation of the filter,
368 * and is used to pass data to the filter.
370 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
373 * Filter uninitialization function. Should deallocate any memory held
374 * by the filter, release any picture references, etc. This does not need
375 * to deallocate the AVFilterContext->priv memory itself.
377 void (*uninit)(AVFilterContext *ctx);
380 * Query formats supported by the filter and its pads. Should set the
381 * in_formats for links connected to its output pads, and out_formats
382 * for links connected to its input pads.
384 * Should return zero on success.
386 int (*query_formats)(AVFilterContext *);
388 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
389 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
392 /** An instance of a filter */
393 struct AVFilterContext
395 const AVClass *av_class; ///< needed for av_log()
397 AVFilter *filter; ///< the AVFilter of which this is an instance
399 char *name; ///< name of this filter instance
401 unsigned input_count; ///< number of input pads
402 AVFilterPad *input_pads; ///< array of input pads
403 AVFilterLink **inputs; ///< array of pointers to input links
405 unsigned output_count; ///< number of output pads
406 AVFilterPad *output_pads; ///< array of output pads
407 AVFilterLink **outputs; ///< array of pointers to output links
409 void *priv; ///< private data for use by the filter
413 * A link between two filters. This contains pointers to the source and
414 * destination filters between which this link exists, and the indices of
415 * the pads involved. In addition, this link also contains the parameters
416 * which have been negotiated and agreed upon between the filter, such as
417 * image dimensions, format, etc
421 AVFilterContext *src; ///< source filter
422 unsigned int srcpad; ///< index of the output pad on the source filter
424 AVFilterContext *dst; ///< dest filter
425 unsigned int dstpad; ///< index of the input pad on the dest filter
427 /** stage of the initialization of the link properties (dimensions, etc) */
429 AVLINK_UNINIT = 0, ///< not started
430 AVLINK_STARTINIT, ///< started, but incomplete
431 AVLINK_INIT ///< complete
434 int w; ///< agreed upon image width
435 int h; ///< agreed upon image height
436 enum PixelFormat format; ///< agreed upon image colorspace
439 * Lists of formats supported by the input and output filters respectively.
440 * These lists are used for negotiating the format to actually be used,
441 * which will be loaded into the format member, above, when chosen.
443 AVFilterFormats *in_formats;
444 AVFilterFormats *out_formats;
447 * The picture reference currently being sent across the link by the source
448 * filter. This is used internally by the filter system to allow
449 * automatic copying of pictures which do not have sufficient permissions
450 * for the destination. This should not be accessed directly by the
453 AVFilterPicRef *srcpic;
455 AVFilterPicRef *cur_pic;
456 AVFilterPicRef *outpic;
460 * Link two filters together.
461 * @param src the source filter
462 * @param srcpad index of the output pad on the source filter
463 * @param dst the destination filter
464 * @param dstpad index of the input pad on the destination filter
465 * @return zero on success
467 int avfilter_link(AVFilterContext *src, unsigned srcpad,
468 AVFilterContext *dst, unsigned dstpad);
471 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
472 * @param filter the filter to negotiate the properties for its inputs
473 * @return zero on successful negotiation
475 int avfilter_config_links(AVFilterContext *filter);
478 * Request a picture buffer with a specific set of permissions
479 * @param link the output link to the filter from which the picture will
481 * @param perms the required access permissions
482 * @return A reference to the picture. This must be unreferenced with
483 * avfilter_unref_pic when you are finished with it.
485 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
488 * Request an input frame from the filter at the other end of the link.
489 * @param link the input link
490 * @return zero on success
492 int avfilter_request_frame(AVFilterLink *link);
495 * Poll a frame from the filter chain.
496 * @param link the input link
497 * @return the number of imediately available frames
499 int avfilter_poll_frame(AVFilterLink *link);
502 * Notify the next filter of the start of a frame.
503 * @param link the output link the frame will be sent over
504 * @param picref A reference to the frame about to be sent. The data for this
505 * frame need only be valid once draw_slice() is called for that
506 * portion. The receiving filter will free this reference when
507 * it no longer needs it.
509 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
512 * Notify the next filter that the current frame has finished
513 * @param link the output link the frame was sent over
515 void avfilter_end_frame(AVFilterLink *link);
518 * Send a slice to the next filter.
519 * @param link the output link over which the frame is being sent
520 * @param y offset in pixels from the top of the image for this slice
521 * @param h height of this slice in pixels
523 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
525 /** Initialize the filter system. Registers all builtin filters */
526 void avfilter_register_all(void);
528 /** Uninitialize the filter system. Unregisters all filters */
529 void avfilter_uninit(void);
532 * Register a filter. This is only needed if you plan to use
533 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
534 * filter can still by instantiated with avfilter_open even if it is not
536 * @param filter the filter to register
538 void avfilter_register(AVFilter *filter);
541 * Gets a filter definition matching the given name.
542 * @param name the filter name to find
543 * @return the filter definition, if any matching one is registered.
544 * NULL if none found.
546 AVFilter *avfilter_get_by_name(const char *name);
549 * Create a filter instance.
550 * @param filter the filter to create an instance of
551 * @param inst_name Name to give to the new instance. Can be NULL for none.
552 * @return Pointer to the new instance on success. NULL on failure.
554 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
557 * Initialize a filter.
558 * @param filter the filter to initialize
559 * @param args A string of parameters to use when initializing the filter.
560 * The format and meaning of this string varies by filter.
561 * @param opaque Any extra non-string data needed by the filter. The meaning
562 * of this parameter varies by filter.
563 * @return zero on success
565 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
569 * @param filter the filter to destroy
571 void avfilter_destroy(AVFilterContext *filter);
574 * Insert a filter in the middle of an existing link.
575 * @param link the link into which the filter should be inserted
576 * @param filt the filter to be inserted
577 * @param in the input pad on the filter to connect
578 * @param out the output pad on the filter to connect
579 * @return zero on success
581 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
582 unsigned in, unsigned out);
586 * @param idx Insertion point. Pad is inserted at the end if this point
587 * is beyond the end of the list of pads.
588 * @param count Pointer to the number of pads in the list
589 * @param padidx_off Offset within an AVFilterLink structure to the element
590 * to increment when inserting a new pad causes link
591 * numbering to change
592 * @param pads Pointer to the pointer to the beginning of the list of pads
593 * @param links Pointer to the pointer to the beginning of the list of links
594 * @param newpad The new pad to add. A copy is made when adding.
596 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
597 AVFilterPad **pads, AVFilterLink ***links,
598 AVFilterPad *newpad);
600 /** insert a new input pad for the filter */
601 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
604 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
605 &f->input_pads, &f->inputs, p);
608 /** insert a new output pad for the filter */
609 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
612 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
613 &f->output_pads, &f->outputs, p);
616 #endif /* FFMPEG_AVFILTER_H */