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 20
29 #define LIBAVFILTER_VERSION_MICRO 1
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 * Return the LIBAVFILTER_VERSION_INT constant.
45 unsigned avfilter_version(void);
48 * Return the libavfilter build-time configuration.
50 const char *avfilter_configuration(void);
53 * Return 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
108 int64_t pos; ///< byte position in stream, -1 if unknown
110 AVRational pixel_aspect; ///< pixel aspect ratio
112 int perms; ///< permissions
113 #define AV_PERM_READ 0x01 ///< can read from the buffer
114 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
115 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
116 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
117 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
119 int interlaced; ///< is frame interlaced
124 * Add a new reference to a picture.
125 * @param ref an existing reference to the picture
126 * @param pmask a bitmask containing the allowable permissions in the new
128 * @return a new reference to the picture with the same properties as the
129 * old, excluding any permissions denied by pmask
131 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
134 * Remove a reference to a picture. If this is the last reference to the
135 * picture, the picture itself is also automatically freed.
136 * @param ref reference to the picture
138 void avfilter_unref_pic(AVFilterPicRef *ref);
141 * A list of supported formats for one end of a filter link. This is used
142 * during the format negotiation process to try to pick the best format to
143 * use to minimize the number of necessary conversions. Each filter gives a
144 * list of the formats supported by each input and output pad. The list
145 * given for each pad need not be distinct - they may be references to the
146 * same list of formats, as is often the case when a filter supports multiple
147 * formats, but will always output the same format as it is given in input.
149 * In this way, a list of possible input formats and a list of possible
150 * output formats are associated with each link. When a set of formats is
151 * negotiated over a link, the input and output lists are merged to form a
152 * new list containing only the common elements of each list. In the case
153 * that there were no common elements, a format conversion is necessary.
154 * Otherwise, the lists are merged, and all other links which reference
155 * either of the format lists involved in the merge are also affected.
157 * For example, consider the filter chain:
158 * filter (a) --> (b) filter (b) --> (c) filter
160 * where the letters in parenthesis indicate a list of formats supported on
161 * the input or output of the link. Suppose the lists are as follows:
166 * First, the first link's lists are merged, yielding:
167 * filter (a) --> (a) filter (a) --> (c) filter
169 * Notice that format list (b) now refers to the same list as filter list (a).
170 * Next, the lists for the second link are merged, yielding:
171 * filter (a) --> (a) filter (a) --> (a) filter
175 * Unfortunately, when the format lists at the two ends of a link are merged,
176 * we must ensure that all links which reference either pre-merge format list
177 * get updated as well. Therefore, we have the format list structure store a
178 * pointer to each of the pointers to itself.
180 typedef struct AVFilterFormats AVFilterFormats;
181 struct AVFilterFormats
183 unsigned format_count; ///< number of formats
184 enum PixelFormat *formats; ///< list of pixel formats
186 unsigned refcount; ///< number of references to this list
187 AVFilterFormats ***refs; ///< references to this list
191 * Create a list of supported formats. This is intended for use in
192 * AVFilter->query_formats().
193 * @param pix_fmt list of pixel formats, terminated by PIX_FMT_NONE
194 * @return the format list, with no existing references
196 AVFilterFormats *avfilter_make_format_list(const enum PixelFormat *pix_fmts);
199 * Add pix_fmt to the list of pixel formats contained in *avff.
200 * If *avff is NULL the function allocates the filter formats struct
201 * and puts its pointer in *avff.
203 * @return a non negative value in case of success, or a negative
204 * value corresponding to an AVERROR code in case of error
206 int avfilter_add_colorspace(AVFilterFormats **avff, enum PixelFormat pix_fmt);
209 * Return a list of all colorspaces supported by FFmpeg.
211 AVFilterFormats *avfilter_all_colorspaces(void);
214 * Return a format list which contains the intersection of the formats of
215 * a and b. Also, all the references of a, all the references of b, and
216 * a and b themselves will be deallocated.
218 * If a and b do not share any common formats, neither is modified, and NULL
221 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
224 * Add *ref as a new reference to formats.
225 * That is the pointers will point like in the ascii art below:
227 * |formats |<--------.
228 * | ____ | ____|___________________
230 * | |* * | | | | | | AVFilterLink
231 * | |* *--------->|*ref|
232 * | |____| | | |____|
233 * |________| |________________________
235 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
238 * If *ref is non-NULL, remove *ref as a reference to the format list
239 * it currently points to, deallocates that list if this was the last
240 * reference, and sets *ref to NULL.
243 * ________ ________ NULL
244 * |formats |<--------. |formats | ^
245 * | ____ | ____|________________ | ____ | ____|________________
246 * | |refs| | | __|_ | |refs| | | __|_
247 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
248 * | |* *--------->|*ref| | |* | | | |*ref|
249 * | |____| | | |____| | |____| | | |____|
250 * |________| |_____________________ |________| |_____________________
252 void avfilter_formats_unref(AVFilterFormats **ref);
258 * |formats |<---------. |formats |<---------.
259 * | ____ | ___|___ | ____ | ___|___
260 * | |refs| | | | | | |refs| | | | | NULL
261 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
262 * | |* * | | |_______| | |* * | | |_______| ___|___
263 * | |____| | | |____| | | | |
264 * |________| |________| |*oldref|
267 void avfilter_formats_changeref(AVFilterFormats **oldref,
268 AVFilterFormats **newref);
271 * A filter pad used for either input or output.
276 * Pad name. The name is unique among inputs and among outputs, but an
277 * input may have the same name as an output. This may be NULL if this
278 * pad has no need to ever be referenced by name.
283 * AVFilterPad type. Only video supported now, hopefully someone will
284 * add audio in the future.
286 enum AVMediaType type;
289 * Minimum required permissions on incoming buffers. Any buffer with
290 * insufficient permissions will be automatically copied by the filter
291 * system to a new buffer which provides the needed access permissions.
298 * Permissions which are not accepted on incoming buffers. Any buffer
299 * which has any of these permissions set will be automatically copied
300 * by the filter system to a new buffer which does not have those
301 * permissions. This can be used to easily disallow buffers with
309 * Callback called before passing the first slice of a new frame. If
310 * NULL, the filter layer will default to storing a reference to the
311 * picture inside the link structure.
313 * Input video pads only.
315 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
318 * Callback function to get a buffer. If NULL, the filter system will
319 * use avfilter_default_get_video_buffer().
321 * Input video pads only.
323 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
326 * Callback called after the slices of a frame are completely sent. If
327 * NULL, the filter layer will default to releasing the reference stored
328 * in the link structure during start_frame().
330 * Input video pads only.
332 void (*end_frame)(AVFilterLink *link);
335 * Slice drawing callback. This is where a filter receives video data
336 * and should do its processing.
338 * Input video pads only.
340 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
343 * Frame poll callback. This returns the number of immediately available
344 * frames. It should return a positive value if the next request_frame()
345 * is guaranteed to return one frame (with no delay).
347 * Defaults to just calling the source poll_frame() method.
349 * Output video pads only.
351 int (*poll_frame)(AVFilterLink *link);
354 * Frame request callback. A call to this should result in at least one
355 * frame being output over the given link. This should return zero on
356 * success, and another value on error.
358 * Output video pads only.
360 int (*request_frame)(AVFilterLink *link);
363 * Link configuration callback.
365 * For output pads, this should set the link properties such as
366 * width/height. This should NOT set the format property - that is
367 * negotiated between filters by the filter system using the
368 * query_formats() callback before this function is called.
370 * For input pads, this should check the properties of the link, and update
371 * the filter's internal state as necessary.
373 * For both input and output filters, this should return zero on success,
374 * and another value on error.
376 int (*config_props)(AVFilterLink *link);
379 /** default handler for start_frame() for video inputs */
380 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
381 /** default handler for draw_slice() for video inputs */
382 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
383 /** default handler for end_frame() for video inputs */
384 void avfilter_default_end_frame(AVFilterLink *link);
385 /** default handler for config_props() for video outputs */
386 int avfilter_default_config_output_link(AVFilterLink *link);
387 /** default handler for config_props() for video inputs */
388 int avfilter_default_config_input_link (AVFilterLink *link);
389 /** default handler for get_video_buffer() for video inputs */
390 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
391 int perms, int w, int h);
393 * A helper for query_formats() which sets all links to the same list of
394 * formats. If there are no links hooked to this filter, the list of formats is
397 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
398 /** Default handler for query_formats() */
399 int avfilter_default_query_formats(AVFilterContext *ctx);
401 /** start_frame() handler for filters which simply pass video along */
402 void avfilter_null_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
404 /** draw_slice() handler for filters which simply pass video along */
405 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
407 /** end_frame() handler for filters which simply pass video along */
408 void avfilter_null_end_frame(AVFilterLink *link);
410 /** get_video_buffer() handler for filters which simply pass video along */
411 AVFilterPicRef *avfilter_null_get_video_buffer(AVFilterLink *link,
412 int perms, int w, int h);
415 * Filter definition. This defines the pads a filter contains, and all the
416 * callback functions used to interact with the filter.
418 typedef struct AVFilter
420 const char *name; ///< filter name
422 int priv_size; ///< size of private data to allocate for the filter
425 * Filter initialization function. Args contains the user-supplied
426 * parameters. FIXME: maybe an AVOption-based system would be better?
427 * opaque is data provided by the code requesting creation of the filter,
428 * and is used to pass data to the filter.
430 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
433 * Filter uninitialization function. Should deallocate any memory held
434 * by the filter, release any picture references, etc. This does not need
435 * to deallocate the AVFilterContext->priv memory itself.
437 void (*uninit)(AVFilterContext *ctx);
440 * Queries formats supported by the filter and its pads, and sets the
441 * in_formats for links connected to its output pads, and out_formats
442 * for links connected to its input pads.
444 * @return zero on success, a negative value corresponding to an
445 * AVERROR code otherwise
447 int (*query_formats)(AVFilterContext *);
449 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
450 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
453 * A description for the filter. You should use the
454 * NULL_IF_CONFIG_SMALL() macro to define it.
456 const char *description;
459 /** An instance of a filter */
460 struct AVFilterContext
462 const AVClass *av_class; ///< needed for av_log()
464 AVFilter *filter; ///< the AVFilter of which this is an instance
466 char *name; ///< name of this filter instance
468 unsigned input_count; ///< number of input pads
469 AVFilterPad *input_pads; ///< array of input pads
470 AVFilterLink **inputs; ///< array of pointers to input links
472 unsigned output_count; ///< number of output pads
473 AVFilterPad *output_pads; ///< array of output pads
474 AVFilterLink **outputs; ///< array of pointers to output links
476 void *priv; ///< private data for use by the filter
480 * A link between two filters. This contains pointers to the source and
481 * destination filters between which this link exists, and the indexes of
482 * the pads involved. In addition, this link also contains the parameters
483 * which have been negotiated and agreed upon between the filter, such as
484 * image dimensions, format, etc.
488 AVFilterContext *src; ///< source filter
489 unsigned int srcpad; ///< index of the output pad on the source filter
491 AVFilterContext *dst; ///< dest filter
492 unsigned int dstpad; ///< index of the input pad on the dest filter
494 /** stage of the initialization of the link properties (dimensions, etc) */
496 AVLINK_UNINIT = 0, ///< not started
497 AVLINK_STARTINIT, ///< started, but incomplete
498 AVLINK_INIT ///< complete
501 int w; ///< agreed upon image width
502 int h; ///< agreed upon image height
503 enum PixelFormat format; ///< agreed upon image colorspace
506 * Lists of formats supported by the input and output filters respectively.
507 * These lists are used for negotiating the format to actually be used,
508 * which will be loaded into the format member, above, when chosen.
510 AVFilterFormats *in_formats;
511 AVFilterFormats *out_formats;
514 * The picture reference currently being sent across the link by the source
515 * filter. This is used internally by the filter system to allow
516 * automatic copying of pictures which do not have sufficient permissions
517 * for the destination. This should not be accessed directly by the
520 AVFilterPicRef *srcpic;
522 AVFilterPicRef *cur_pic;
523 AVFilterPicRef *outpic;
527 * Link two filters together.
528 * @param src the source filter
529 * @param srcpad index of the output pad on the source filter
530 * @param dst the destination filter
531 * @param dstpad index of the input pad on the destination filter
532 * @return zero on success
534 int avfilter_link(AVFilterContext *src, unsigned srcpad,
535 AVFilterContext *dst, unsigned dstpad);
538 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
539 * @param filter the filter to negotiate the properties for its inputs
540 * @return zero on successful negotiation
542 int avfilter_config_links(AVFilterContext *filter);
545 * Request a picture buffer with a specific set of permissions.
546 * @param link the output link to the filter from which the picture will
548 * @param perms the required access permissions
549 * @param w the minimum width of the buffer to allocate
550 * @param h the minimum height of the buffer to allocate
551 * @return A reference to the picture. This must be unreferenced with
552 * avfilter_unref_pic when you are finished with it.
554 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
558 * Request an input frame from the filter at the other end of the link.
559 * @param link the input link
560 * @return zero on success
562 int avfilter_request_frame(AVFilterLink *link);
565 * Poll a frame from the filter chain.
566 * @param link the input link
567 * @return the number of immediately available frames, a negative
568 * number in case of error
570 int avfilter_poll_frame(AVFilterLink *link);
573 * Notifie the next filter of the start of a frame.
574 * @param link the output link the frame will be sent over
575 * @param picref A reference to the frame about to be sent. The data for this
576 * frame need only be valid once draw_slice() is called for that
577 * portion. The receiving filter will free this reference when
578 * it no longer needs it.
580 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
583 * Notifie the next filter that the current frame has finished.
584 * @param link the output link the frame was sent over
586 void avfilter_end_frame(AVFilterLink *link);
589 * Send a slice to the next filter.
591 * Slices have to be provided in sequential order, either in
592 * top-bottom or bottom-top order. If slices are provided in
593 * non-sequential order the behavior of the function is undefined.
595 * @param link the output link over which the frame is being sent
596 * @param y offset in pixels from the top of the image for this slice
597 * @param h height of this slice in pixels
598 * @param slice_dir the assumed direction for sending slices,
599 * from the top slice to the bottom slice if the value is 1,
600 * from the bottom slice to the top slice if the value is -1,
601 * for other values the behavior of the function is undefined.
603 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
605 /** Initialize the filter system. Register all builtin filters. */
606 void avfilter_register_all(void);
608 /** Uninitialize the filter system. Unregister all filters. */
609 void avfilter_uninit(void);
612 * Register a filter. This is only needed if you plan to use
613 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
614 * filter can still by instantiated with avfilter_open even if it is not
616 * @param filter the filter to register
617 * @return 0 if the registration was succesfull, a negative value
620 int avfilter_register(AVFilter *filter);
623 * Get a filter definition matching the given name.
624 * @param name the filter name to find
625 * @return the filter definition, if any matching one is registered.
626 * NULL if none found.
628 AVFilter *avfilter_get_by_name(const char *name);
631 * If filter is NULL, returns a pointer to the first registered filter pointer,
632 * if filter is non-NULL, returns the next pointer after filter.
633 * If the returned pointer points to NULL, the last registered filter
634 * was already reached.
636 AVFilter **av_filter_next(AVFilter **filter);
639 * Create a filter instance.
640 * @param filter the filter to create an instance of
641 * @param inst_name Name to give to the new instance. Can be NULL for none.
642 * @return Pointer to the new instance on success. NULL on failure.
644 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
647 * Initialize a filter.
648 * @param filter the filter to initialize
649 * @param args A string of parameters to use when initializing the filter.
650 * The format and meaning of this string varies by filter.
651 * @param opaque Any extra non-string data needed by the filter. The meaning
652 * of this parameter varies by filter.
653 * @return zero on success
655 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
659 * @param filter the filter to destroy
661 void avfilter_destroy(AVFilterContext *filter);
664 * Insert a filter in the middle of an existing link.
665 * @param link the link into which the filter should be inserted
666 * @param filt the filter to be inserted
667 * @param in the input pad on the filter to connect
668 * @param out the output pad on the filter to connect
669 * @return zero on success
671 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
672 unsigned in, unsigned out);
676 * @param idx Insertion point. Pad is inserted at the end if this point
677 * is beyond the end of the list of pads.
678 * @param count Pointer to the number of pads in the list
679 * @param padidx_off Offset within an AVFilterLink structure to the element
680 * to increment when inserting a new pad causes link
681 * numbering to change
682 * @param pads Pointer to the pointer to the beginning of the list of pads
683 * @param links Pointer to the pointer to the beginning of the list of links
684 * @param newpad The new pad to add. A copy is made when adding.
686 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
687 AVFilterPad **pads, AVFilterLink ***links,
688 AVFilterPad *newpad);
690 /** Insert a new input pad for the filter. */
691 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
694 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
695 &f->input_pads, &f->inputs, p);
698 /** Insert a new output pad for the filter. */
699 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
702 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
703 &f->output_pads, &f->outputs, p);
706 #endif /* AVFILTER_AVFILTER_H */