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 AVFILTER_AVFILTER_H
23 #define AVFILTER_AVFILTER_H
25 #include "libavutil/avutil.h"
27 #define LIBAVFILTER_VERSION_MAJOR 1
28 #define LIBAVFILTER_VERSION_MINOR 14
29 #define LIBAVFILTER_VERSION_MICRO 0
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
40 #include "libavcodec/avcodec.h"
43 * Returns the LIBAVFILTER_VERSION_INT constant.
45 unsigned avfilter_version(void);
48 * Returns the libavfilter build-time configuration.
50 const char *avfilter_configuration(void);
53 * Returns the libavfilter license.
55 const char *avfilter_license(void);
58 typedef struct AVFilterContext AVFilterContext;
59 typedef struct AVFilterLink AVFilterLink;
60 typedef struct AVFilterPad AVFilterPad;
62 /* TODO: look for other flags which may be useful in this structure (interlace
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.
70 typedef struct AVFilterPic
72 uint8_t *data[4]; ///< picture data for each plane
73 int linesize[4]; ///< number of bytes per line
74 enum PixelFormat format; ///< colorspace
76 unsigned refcount; ///< number of references to this image
78 /** private data to be used by a custom free function */
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.
86 void (*free)(struct AVFilterPic *pic);
88 int w, h; ///< width and height of the allocated buffer
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.
97 * TODO: add anything necessary for frame reordering
99 typedef struct AVFilterPicRef
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
107 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
109 AVRational pixel_aspect; ///< pixel aspect ratio
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
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
124 * @return a new reference to the picture with the same properties as the
125 * old, excluding any permissions denied by pmask
127 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
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
134 void avfilter_unref_pic(AVFilterPicRef *ref);
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.
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.
153 * For example, consider the filter chain:
154 * filter (a) --> (b) filter (b) --> (c) filter
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:
162 * First, the first link's lists are merged, yielding:
163 * filter (a) --> (a) filter (a) --> (c) filter
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
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.
176 typedef struct AVFilterFormats AVFilterFormats;
177 struct AVFilterFormats
179 unsigned format_count; ///< number of formats
180 enum PixelFormat *formats; ///< list of pixel formats
182 unsigned refcount; ///< number of references to this list
183 AVFilterFormats ***refs; ///< references to this list
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
192 AVFilterFormats *avfilter_make_format_list(const enum PixelFormat *pix_fmts);
195 * Adds pix_fmt to the list of pixel formats contained in *avff.
196 * If *avff is NULL the function allocates the filter formats struct
197 * and puts its pointer in *avff.
199 * @return a non negative value in case of success, or a negative
200 * value corresponding to an AVERROR code in case of error
202 int avfilter_add_colorspace(AVFilterFormats **avff, enum PixelFormat pix_fmt);
205 * Returns a list of all colorspaces supported by FFmpeg.
207 AVFilterFormats *avfilter_all_colorspaces(void);
210 * Returns a format list which contains the intersection of the formats of
211 * a and b. Also, all the references of a, all the references of b, and
212 * a and b themselves will be deallocated.
214 * If a and b do not share any common formats, neither is modified, and NULL
217 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
220 * Adds *ref as a new reference to formats.
221 * That is the pointers will point like in the ascii art below:
223 * |formats |<--------.
224 * | ____ | ____|___________________
226 * | |* * | | | | | | AVFilterLink
227 * | |* *--------->|*ref|
228 * | |____| | | |____|
229 * |________| |________________________
231 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
234 * Removes *ref as a reference to the format list it currently points to,
235 * deallocates that list if this was the last reference, and sets *ref to NULL.
238 * ________ ________ NULL
239 * |formats |<--------. |formats | ^
240 * | ____ | ____|________________ | ____ | ____|________________
241 * | |refs| | | __|_ | |refs| | | __|_
242 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
243 * | |* *--------->|*ref| | |* | | | |*ref|
244 * | |____| | | |____| | |____| | | |____|
245 * |________| |_____________________ |________| |_____________________
247 void avfilter_formats_unref(AVFilterFormats **ref);
253 * |formats |<---------. |formats |<---------.
254 * | ____ | ___|___ | ____ | ___|___
255 * | |refs| | | | | | |refs| | | | | NULL
256 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
257 * | |* * | | |_______| | |* * | | |_______| ___|___
258 * | |____| | | |____| | | | |
259 * |________| |________| |*oldref|
262 void avfilter_formats_changeref(AVFilterFormats **oldref,
263 AVFilterFormats **newref);
266 * A filter pad used for either input or output.
271 * Pad name. The name is unique among inputs and among outputs, but an
272 * input may have the same name as an output. This may be NULL if this
273 * pad has no need to ever be referenced by name.
278 * AVFilterPad type. Only video supported now, hopefully someone will
279 * add audio in the future.
284 * Minimum required permissions on incoming buffers. Any buffer with
285 * insufficient permissions will be automatically copied by the filter
286 * system to a new buffer which provides the needed access permissions.
293 * Permissions which are not accepted on incoming buffers. Any buffer
294 * which has any of these permissions set will be automatically copied
295 * by the filter system to a new buffer which does not have those
296 * permissions. This can be used to easily disallow buffers with
304 * Callback called before passing the first slice of a new frame. If
305 * NULL, the filter layer will default to storing a reference to the
306 * picture inside the link structure.
308 * Input video pads only.
310 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
313 * Callback function to get a buffer. If NULL, the filter system will
314 * use avfilter_default_get_video_buffer().
316 * Input video pads only.
318 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
321 * Callback called after the slices of a frame are completely sent. If
322 * NULL, the filter layer will default to releasing the reference stored
323 * in the link structure during start_frame().
325 * Input video pads only.
327 void (*end_frame)(AVFilterLink *link);
330 * Slice drawing callback. This is where a filter receives video data
331 * and should do its processing.
333 * Input video pads only.
335 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
338 * Frame poll callback. This returns the number of immediately available
339 * frames. It should return a positive value if the next request_frame()
340 * is guaranteed to return one frame (with no delay).
342 * Defaults to just calling the source poll_frame() method.
344 * Output video pads only.
346 int (*poll_frame)(AVFilterLink *link);
349 * Frame request callback. A call to this should result in at least one
350 * frame being output over the given link. This should return zero on
351 * success, and another value on error.
353 * Output video pads only.
355 int (*request_frame)(AVFilterLink *link);
358 * Link configuration callback.
360 * For output pads, this should set the link properties such as
361 * width/height. This should NOT set the format property - that is
362 * negotiated between filters by the filter system using the
363 * query_formats() callback before this function is called.
365 * For input pads, this should check the properties of the link, and update
366 * the filter's internal state as necessary.
368 * For both input and output filters, this should return zero on success,
369 * and another value on error.
371 int (*config_props)(AVFilterLink *link);
374 /** default handler for start_frame() for video inputs */
375 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
376 /** default handler for draw_slice() for video inputs */
377 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
378 /** default handler for end_frame() for video inputs */
379 void avfilter_default_end_frame(AVFilterLink *link);
380 /** default handler for config_props() for video outputs */
381 int avfilter_default_config_output_link(AVFilterLink *link);
382 /** default handler for config_props() for video inputs */
383 int avfilter_default_config_input_link (AVFilterLink *link);
384 /** default handler for get_video_buffer() for video inputs */
385 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
386 int perms, int w, int h);
388 * A helper for query_formats() which sets all links to the same list of
389 * formats. If there are no links hooked to this filter, the list of formats is
392 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
393 /** Default handler for query_formats() */
394 int avfilter_default_query_formats(AVFilterContext *ctx);
397 * Filter definition. This defines the pads a filter contains, and all the
398 * callback functions used to interact with the filter.
400 typedef struct AVFilter
402 const char *name; ///< filter name
404 int priv_size; ///< size of private data to allocate for the filter
407 * Filter initialization function. Args contains the user-supplied
408 * parameters. FIXME: maybe an AVOption-based system would be better?
409 * opaque is data provided by the code requesting creation of the filter,
410 * and is used to pass data to the filter.
412 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
415 * Filter uninitialization function. Should deallocate any memory held
416 * by the filter, release any picture references, etc. This does not need
417 * to deallocate the AVFilterContext->priv memory itself.
419 void (*uninit)(AVFilterContext *ctx);
422 * Query formats supported by the filter and its pads. Should set the
423 * in_formats for links connected to its output pads, and out_formats
424 * for links connected to its input pads.
426 * Should return zero on success.
428 int (*query_formats)(AVFilterContext *);
430 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
431 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
434 * A description for the filter. You should use the
435 * NULL_IF_CONFIG_SMALL() macro to define it.
437 const char *description;
440 /** An instance of a filter */
441 struct AVFilterContext
443 const AVClass *av_class; ///< needed for av_log()
445 AVFilter *filter; ///< the AVFilter of which this is an instance
447 char *name; ///< name of this filter instance
449 unsigned input_count; ///< number of input pads
450 AVFilterPad *input_pads; ///< array of input pads
451 AVFilterLink **inputs; ///< array of pointers to input links
453 unsigned output_count; ///< number of output pads
454 AVFilterPad *output_pads; ///< array of output pads
455 AVFilterLink **outputs; ///< array of pointers to output links
457 void *priv; ///< private data for use by the filter
461 * A link between two filters. This contains pointers to the source and
462 * destination filters between which this link exists, and the indexes of
463 * the pads involved. In addition, this link also contains the parameters
464 * which have been negotiated and agreed upon between the filter, such as
465 * image dimensions, format, etc.
469 AVFilterContext *src; ///< source filter
470 unsigned int srcpad; ///< index of the output pad on the source filter
472 AVFilterContext *dst; ///< dest filter
473 unsigned int dstpad; ///< index of the input pad on the dest filter
475 /** stage of the initialization of the link properties (dimensions, etc) */
477 AVLINK_UNINIT = 0, ///< not started
478 AVLINK_STARTINIT, ///< started, but incomplete
479 AVLINK_INIT ///< complete
482 int w; ///< agreed upon image width
483 int h; ///< agreed upon image height
484 enum PixelFormat format; ///< agreed upon image colorspace
487 * Lists of formats supported by the input and output filters respectively.
488 * These lists are used for negotiating the format to actually be used,
489 * which will be loaded into the format member, above, when chosen.
491 AVFilterFormats *in_formats;
492 AVFilterFormats *out_formats;
495 * The picture reference currently being sent across the link by the source
496 * filter. This is used internally by the filter system to allow
497 * automatic copying of pictures which do not have sufficient permissions
498 * for the destination. This should not be accessed directly by the
501 AVFilterPicRef *srcpic;
503 AVFilterPicRef *cur_pic;
504 AVFilterPicRef *outpic;
508 * Links two filters together.
509 * @param src the source filter
510 * @param srcpad index of the output pad on the source filter
511 * @param dst the destination filter
512 * @param dstpad index of the input pad on the destination filter
513 * @return zero on success
515 int avfilter_link(AVFilterContext *src, unsigned srcpad,
516 AVFilterContext *dst, unsigned dstpad);
519 * Negotiates the colorspace, dimensions, etc of all inputs to a filter.
520 * @param filter the filter to negotiate the properties for its inputs
521 * @return zero on successful negotiation
523 int avfilter_config_links(AVFilterContext *filter);
526 * Requests a picture buffer with a specific set of permissions.
527 * @param link the output link to the filter from which the picture will
529 * @param perms the required access permissions
530 * @param w the minimum width of the buffer to allocate
531 * @param h the minimum height of the buffer to allocate
532 * @return A reference to the picture. This must be unreferenced with
533 * avfilter_unref_pic when you are finished with it.
535 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
539 * Requests an input frame from the filter at the other end of the link.
540 * @param link the input link
541 * @return zero on success
543 int avfilter_request_frame(AVFilterLink *link);
546 * Polls a frame from the filter chain.
547 * @param link the input link
548 * @return the number of immediately available frames, a negative
549 * number in case of error
551 int avfilter_poll_frame(AVFilterLink *link);
554 * Notifies the next filter of the start of a frame.
555 * @param link the output link the frame will be sent over
556 * @param picref A reference to the frame about to be sent. The data for this
557 * frame need only be valid once draw_slice() is called for that
558 * portion. The receiving filter will free this reference when
559 * it no longer needs it.
561 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
564 * Notifies the next filter that the current frame has finished.
565 * @param link the output link the frame was sent over
567 void avfilter_end_frame(AVFilterLink *link);
570 * Sends a slice to the next filter.
572 * Slices have to be provided in sequential order, either in
573 * top-bottom or bottom-top order. If slices are provided in
574 * non-sequential order the behavior of the function is undefined.
576 * @param link the output link over which the frame is being sent
577 * @param y offset in pixels from the top of the image for this slice
578 * @param h height of this slice in pixels
579 * @param slice_dir the assumed direction for sending slices,
580 * from the top slice to the bottom slice if the value is 1,
581 * from the bottom slice to the top slice if the value is -1,
582 * for other values the behavior of the function is undefined.
584 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
586 /** Initializes the filter system. Registers all builtin filters. */
587 void avfilter_register_all(void);
589 /** Uninitializes the filter system. Unregisters all filters. */
590 void avfilter_uninit(void);
593 * Registers a filter. This is only needed if you plan to use
594 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
595 * filter can still by instantiated with avfilter_open even if it is not
597 * @param filter the filter to register
598 * @return 0 if the registration was succesfull, a negative value
601 int avfilter_register(AVFilter *filter);
604 * Gets a filter definition matching the given name.
605 * @param name the filter name to find
606 * @return the filter definition, if any matching one is registered.
607 * NULL if none found.
609 AVFilter *avfilter_get_by_name(const char *name);
612 * If filter is NULL, returns a pointer to the first registered filter pointer,
613 * if filter is non-NULL, returns the next pointer after filter.
614 * If the returned pointer points to NULL, the last registered filter
615 * was already reached.
617 AVFilter **av_filter_next(AVFilter **filter);
620 * Creates a filter instance.
621 * @param filter the filter to create an instance of
622 * @param inst_name Name to give to the new instance. Can be NULL for none.
623 * @return Pointer to the new instance on success. NULL on failure.
625 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
628 * Initializes a filter.
629 * @param filter the filter to initialize
630 * @param args A string of parameters to use when initializing the filter.
631 * The format and meaning of this string varies by filter.
632 * @param opaque Any extra non-string data needed by the filter. The meaning
633 * of this parameter varies by filter.
634 * @return zero on success
636 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
640 * @param filter the filter to destroy
642 void avfilter_destroy(AVFilterContext *filter);
645 * Inserts a filter in the middle of an existing link.
646 * @param link the link into which the filter should be inserted
647 * @param filt the filter to be inserted
648 * @param in the input pad on the filter to connect
649 * @param out the output pad on the filter to connect
650 * @return zero on success
652 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
653 unsigned in, unsigned out);
657 * @param idx Insertion point. Pad is inserted at the end if this point
658 * is beyond the end of the list of pads.
659 * @param count Pointer to the number of pads in the list
660 * @param padidx_off Offset within an AVFilterLink structure to the element
661 * to increment when inserting a new pad causes link
662 * numbering to change
663 * @param pads Pointer to the pointer to the beginning of the list of pads
664 * @param links Pointer to the pointer to the beginning of the list of links
665 * @param newpad The new pad to add. A copy is made when adding.
667 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
668 AVFilterPad **pads, AVFilterLink ***links,
669 AVFilterPad *newpad);
671 /** Inserts a new input pad for the filter. */
672 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
675 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
676 &f->input_pads, &f->inputs, p);
679 /** Inserts a new output pad for the filter. */
680 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
683 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
684 &f->output_pads, &f->outputs, p);
687 #endif /* AVFILTER_AVFILTER_H */