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 #define LIBAVFILTER_VERSION_MAJOR 1
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
38 #include "libavcodec/avcodec.h"
41 * Returns the LIBAVFILTER_VERSION_INT constant.
43 unsigned avfilter_version(void);
45 typedef struct AVFilterContext AVFilterContext;
46 typedef struct AVFilterLink AVFilterLink;
47 typedef struct AVFilterPad AVFilterPad;
49 /* TODO: look for other flags which may be useful in this structure (interlace
53 * A reference-counted picture data type used by the filter system. Filters
54 * should not store pointers to this structure directly, but instead use the
55 * AVFilterPicRef structure below.
57 typedef struct AVFilterPic
59 uint8_t *data[4]; ///< picture data for each plane
60 int linesize[4]; ///< number of bytes per line
61 enum PixelFormat format; ///< colorspace
63 unsigned refcount; ///< number of references to this image
65 /** private data to be used by a custom free function */
68 * A pointer to the function to deallocate this image if the default
69 * function is not sufficient. This could, for example, add the memory
70 * back into a memory pool to be reused later without the overhead of
71 * reallocating it from scratch.
73 void (*free)(struct AVFilterPic *pic);
75 int w, h; ///< width and height of the allocated buffer
79 * A reference to an AVFilterPic. Since filters can manipulate the origin of
80 * a picture to, for example, crop image without any memcpy, the picture origin
81 * and dimensions are per-reference properties. Linesize is also useful for
82 * image flipping, frame to field filters, etc, and so is also per-reference.
84 * TODO: add anything necessary for frame reordering
86 typedef struct AVFilterPicRef
88 AVFilterPic *pic; ///< the picture that this is a reference to
89 uint8_t *data[4]; ///< picture data for each plane
90 int linesize[4]; ///< number of bytes per line
91 int w; ///< image width
92 int h; ///< image height
94 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
96 AVRational pixel_aspect; ///< pixel aspect ratio
98 int perms; ///< permissions
99 #define AV_PERM_READ 0x01 ///< can read from the buffer
100 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
101 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
102 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
103 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
107 * Adds a new reference to a picture.
108 * @param ref an existing reference to the picture
109 * @param pmask a bitmask containing the allowable permissions in the new
111 * @return a new reference to the picture with the same properties as the
112 * old, excluding any permissions denied by pmask
114 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
117 * Removes a reference to a picture. If this is the last reference to the
118 * picture, the picture itself is also automatically freed.
119 * @param ref reference to the picture
121 void avfilter_unref_pic(AVFilterPicRef *ref);
124 * A list of supported formats for one end of a filter link. This is used
125 * during the format negotiation process to try to pick the best format to
126 * use to minimize the number of necessary conversions. Each filter gives a
127 * list of the formats supported by each input and output pad. The list
128 * given for each pad need not be distinct - they may be references to the
129 * same list of formats, as is often the case when a filter supports multiple
130 * formats, but will always output the same format as it is given in input.
132 * In this way, a list of possible input formats and a list of possible
133 * output formats are associated with each link. When a set of formats is
134 * negotiated over a link, the input and output lists are merged to form a
135 * new list containing only the common elements of each list. In the case
136 * that there were no common elements, a format conversion is necessary.
137 * Otherwise, the lists are merged, and all other links which reference
138 * either of the format lists involved in the merge are also affected.
140 * For example, consider the filter chain:
141 * filter (a) --> (b) filter (b) --> (c) filter
143 * where the letters in parenthesis indicate a list of formats supported on
144 * the input or output of the link. Suppose the lists are as follows:
149 * First, the first link's lists are merged, yielding:
150 * filter (a) --> (a) filter (a) --> (c) filter
152 * Notice that format list (b) now refers to the same list as filter list (a).
153 * Next, the lists for the second link are merged, yielding:
154 * filter (a) --> (a) filter (a) --> (a) filter
158 * Unfortunately, when the format lists at the two ends of a link are merged,
159 * we must ensure that all links which reference either pre-merge format list
160 * get updated as well. Therefore, we have the format list structure store a
161 * pointer to each of the pointers to itself.
163 typedef struct AVFilterFormats AVFilterFormats;
164 struct AVFilterFormats
166 unsigned format_count; ///< number of formats
167 int *formats; ///< list of formats
169 unsigned refcount; ///< number of references to this list
170 AVFilterFormats ***refs; ///< references to this list
174 * Helper function to create a list of supported formats. This is intended
175 * for use in AVFilter->query_formats().
176 * @param len the number of formats supported
177 * @param ... a list of the supported formats
178 * @return the format list, with no existing references
180 AVFilterFormats *avfilter_make_format_list(int len, ...);
183 * Returns a list of all colorspaces supported by FFmpeg.
185 AVFilterFormats *avfilter_all_colorspaces(void);
188 * Returns a format list which contains the intersection of the formats of
189 * a and b. Also, all the references of a, all the references of b, and
190 * a and b themselves will be deallocated.
192 * If a and b do not share any common formats, neither is modified, and NULL
195 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
198 * Adds *ref as a new reference to formats.
199 * That is the pointers will point like in the ascii art below:
201 * |formats |<--------.
202 * | ____ | ____|___________________
204 * | |* * | | | | | | AVFilterLink
205 * | |* *--------->|*ref|
206 * | |____| | | |____|
207 * |________| |________________________
209 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
212 * Removes *ref as a reference to the format list it currently points to,
213 * deallocates that list if this was the last reference, and sets *ref to NULL.
216 * ________ ________ NULL
217 * |formats |<--------. |formats | ^
218 * | ____ | ____|________________ | ____ | ____|________________
219 * | |refs| | | __|_ | |refs| | | __|_
220 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
221 * | |* *--------->|*ref| | |* | | | |*ref|
222 * | |____| | | |____| | |____| | | |____|
223 * |________| |_____________________ |________| |_____________________
225 void avfilter_formats_unref(AVFilterFormats **ref);
231 * |formats |<---------. |formats |<---------.
232 * | ____ | ___|___ | ____ | ___|___
233 * | |refs| | | | | | |refs| | | | | NULL
234 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
235 * | |* * | | |_______| | |* * | | |_______| ___|___
236 * | |____| | | |____| | | | |
237 * |________| |________| |*oldref|
240 void avfilter_formats_changeref(AVFilterFormats **oldref,
241 AVFilterFormats **newref);
244 * A filter pad used for either input or output.
249 * Pad name. The name is unique among inputs and among outputs, but an
250 * input may have the same name as an output. This may be NULL if this
251 * pad has no need to ever be referenced by name.
256 * AVFilterPad type. Only video supported now, hopefully someone will
257 * add audio in the future.
262 * Minimum required permissions on incoming buffers. Any buffer with
263 * insufficient permissions will be automatically copied by the filter
264 * system to a new buffer which provides the needed access permissions.
271 * Permissions which are not accepted on incoming buffers. Any buffer
272 * which has any of these permissions set will be automatically copied
273 * by the filter system to a new buffer which does not have those
274 * permissions. This can be used to easily disallow buffers with
282 * Callback called before passing the first slice of a new frame. If
283 * NULL, the filter layer will default to storing a reference to the
284 * picture inside the link structure.
286 * Input video pads only.
288 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
291 * Callback function to get a buffer. If NULL, the filter system will
292 * handle buffer requests.
294 * Input video pads only.
296 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
299 * Callback called after the slices of a frame are completely sent. If
300 * NULL, the filter layer will default to releasing the reference stored
301 * in the link structure during start_frame().
303 * Input video pads only.
305 void (*end_frame)(AVFilterLink *link);
308 * Slice drawing callback. This is where a filter receives video data
309 * and should do its processing.
311 * Input video pads only.
313 void (*draw_slice)(AVFilterLink *link, int y, int height);
316 * Frame poll callback. This returns the number of immediately available
317 * frames. It should return a positive value if the next request_frame()
318 * is guaranteed to return one frame (with no delay).
320 * Defaults to just calling the source poll_frame() method.
322 * Output video pads only.
324 int (*poll_frame)(AVFilterLink *link);
327 * Frame request callback. A call to this should result in at least one
328 * frame being output over the given link. This should return zero on
329 * success, and another value on error.
331 * Output video pads only.
333 int (*request_frame)(AVFilterLink *link);
336 * Link configuration callback.
338 * For output pads, this should set the link properties such as
339 * width/height. This should NOT set the format property - that is
340 * negotiated between filters by the filter system using the
341 * query_formats() callback before this function is called.
343 * For input pads, this should check the properties of the link, and update
344 * the filter's internal state as necessary.
346 * For both input and output filters, this should return zero on success,
347 * and another value on error.
349 int (*config_props)(AVFilterLink *link);
352 /** default handler for start_frame() for video inputs */
353 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
354 /** default handler for draw_slice() for video inputs */
355 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h);
356 /** default handler for end_frame() for video inputs */
357 void avfilter_default_end_frame(AVFilterLink *link);
358 /** default handler for config_props() for video outputs */
359 int avfilter_default_config_output_link(AVFilterLink *link);
360 /** default handler for config_props() for video inputs */
361 int avfilter_default_config_input_link (AVFilterLink *link);
362 /** default handler for get_video_buffer() for video inputs */
363 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
364 int perms, int w, int h);
366 * A helper for query_formats() which sets all links to the same list of
367 * formats. If there are no links hooked to this filter, the list of formats is
370 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
371 /** Default handler for query_formats() */
372 int avfilter_default_query_formats(AVFilterContext *ctx);
375 * Filter definition. This defines the pads a filter contains, and all the
376 * callback functions used to interact with the filter.
380 const char *name; ///< filter name
382 int priv_size; ///< size of private data to allocate for the filter
385 * Filter initialization function. Args contains the user-supplied
386 * parameters. FIXME: maybe an AVOption-based system would be better?
387 * opaque is data provided by the code requesting creation of the filter,
388 * and is used to pass data to the filter.
390 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
393 * Filter uninitialization function. Should deallocate any memory held
394 * by the filter, release any picture references, etc. This does not need
395 * to deallocate the AVFilterContext->priv memory itself.
397 void (*uninit)(AVFilterContext *ctx);
400 * Query formats supported by the filter and its pads. Should set the
401 * in_formats for links connected to its output pads, and out_formats
402 * for links connected to its input pads.
404 * Should return zero on success.
406 int (*query_formats)(AVFilterContext *);
408 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
409 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
412 /** An instance of a filter */
413 struct AVFilterContext
415 const AVClass *av_class; ///< needed for av_log()
417 AVFilter *filter; ///< the AVFilter of which this is an instance
419 char *name; ///< name of this filter instance
421 unsigned input_count; ///< number of input pads
422 AVFilterPad *input_pads; ///< array of input pads
423 AVFilterLink **inputs; ///< array of pointers to input links
425 unsigned output_count; ///< number of output pads
426 AVFilterPad *output_pads; ///< array of output pads
427 AVFilterLink **outputs; ///< array of pointers to output links
429 void *priv; ///< private data for use by the filter
433 * A link between two filters. This contains pointers to the source and
434 * destination filters between which this link exists, and the indexes of
435 * the pads involved. In addition, this link also contains the parameters
436 * which have been negotiated and agreed upon between the filter, such as
437 * image dimensions, format, etc.
441 AVFilterContext *src; ///< source filter
442 unsigned int srcpad; ///< index of the output pad on the source filter
444 AVFilterContext *dst; ///< dest filter
445 unsigned int dstpad; ///< index of the input pad on the dest filter
447 /** stage of the initialization of the link properties (dimensions, etc) */
449 AVLINK_UNINIT = 0, ///< not started
450 AVLINK_STARTINIT, ///< started, but incomplete
451 AVLINK_INIT ///< complete
454 int w; ///< agreed upon image width
455 int h; ///< agreed upon image height
456 enum PixelFormat format; ///< agreed upon image colorspace
459 * Lists of formats supported by the input and output filters respectively.
460 * These lists are used for negotiating the format to actually be used,
461 * which will be loaded into the format member, above, when chosen.
463 AVFilterFormats *in_formats;
464 AVFilterFormats *out_formats;
467 * The picture reference currently being sent across the link by the source
468 * filter. This is used internally by the filter system to allow
469 * automatic copying of pictures which do not have sufficient permissions
470 * for the destination. This should not be accessed directly by the
473 AVFilterPicRef *srcpic;
475 AVFilterPicRef *cur_pic;
476 AVFilterPicRef *outpic;
480 * Links two filters together.
481 * @param src the source filter
482 * @param srcpad index of the output pad on the source filter
483 * @param dst the destination filter
484 * @param dstpad index of the input pad on the destination filter
485 * @return zero on success
487 int avfilter_link(AVFilterContext *src, unsigned srcpad,
488 AVFilterContext *dst, unsigned dstpad);
491 * Negotiates the colorspace, dimensions, etc of all inputs to a filter.
492 * @param filter the filter to negotiate the properties for its inputs
493 * @return zero on successful negotiation
495 int avfilter_config_links(AVFilterContext *filter);
498 * Requests a picture buffer with a specific set of permissions.
499 * @param link the output link to the filter from which the picture will
501 * @param perms the required access permissions
502 * @param w the minimum width of the buffer to allocate
503 * @param h the minimum height of the buffer to allocate
504 * @return A reference to the picture. This must be unreferenced with
505 * avfilter_unref_pic when you are finished with it.
507 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
511 * Requests an input frame from the filter at the other end of the link.
512 * @param link the input link
513 * @return zero on success
515 int avfilter_request_frame(AVFilterLink *link);
518 * Polls a frame from the filter chain.
519 * @param link the input link
520 * @return the number of immediately available frames, a negative
521 * number in case of error
523 int avfilter_poll_frame(AVFilterLink *link);
526 * Notifies the next filter of the start of a frame.
527 * @param link the output link the frame will be sent over
528 * @param picref A reference to the frame about to be sent. The data for this
529 * frame need only be valid once draw_slice() is called for that
530 * portion. The receiving filter will free this reference when
531 * it no longer needs it.
533 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
536 * Notifies the next filter that the current frame has finished.
537 * @param link the output link the frame was sent over
539 void avfilter_end_frame(AVFilterLink *link);
542 * Sends a slice to the next filter.
543 * @param link the output link over which the frame is being sent
544 * @param y offset in pixels from the top of the image for this slice
545 * @param h height of this slice in pixels
547 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
549 /** Initialize the filter system. Registers all builtin filters */
550 void avfilter_register_all(void);
552 /** Uninitialize the filter system. Unregisters all filters */
553 void avfilter_uninit(void);
556 * Registers a filter. This is only needed if you plan to use
557 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
558 * filter can still by instantiated with avfilter_open even if it is not
560 * @param filter the filter to register
562 void avfilter_register(AVFilter *filter);
565 * Gets a filter definition matching the given name.
566 * @param name the filter name to find
567 * @return the filter definition, if any matching one is registered.
568 * NULL if none found.
570 AVFilter *avfilter_get_by_name(const char *name);
573 * Creates a filter instance.
574 * @param filter the filter to create an instance of
575 * @param inst_name Name to give to the new instance. Can be NULL for none.
576 * @return Pointer to the new instance on success. NULL on failure.
578 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
581 * Initializes a filter.
582 * @param filter the filter to initialize
583 * @param args A string of parameters to use when initializing the filter.
584 * The format and meaning of this string varies by filter.
585 * @param opaque Any extra non-string data needed by the filter. The meaning
586 * of this parameter varies by filter.
587 * @return zero on success
589 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
593 * @param filter the filter to destroy
595 void avfilter_destroy(AVFilterContext *filter);
598 * Inserts a filter in the middle of an existing link.
599 * @param link the link into which the filter should be inserted
600 * @param filt the filter to be inserted
601 * @param in the input pad on the filter to connect
602 * @param out the output pad on the filter to connect
603 * @return zero on success
605 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
606 unsigned in, unsigned out);
610 * @param idx Insertion point. Pad is inserted at the end if this point
611 * is beyond the end of the list of pads.
612 * @param count Pointer to the number of pads in the list
613 * @param padidx_off Offset within an AVFilterLink structure to the element
614 * to increment when inserting a new pad causes link
615 * numbering to change
616 * @param pads Pointer to the pointer to the beginning of the list of pads
617 * @param links Pointer to the pointer to the beginning of the list of links
618 * @param newpad The new pad to add. A copy is made when adding.
620 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
621 AVFilterPad **pads, AVFilterLink ***links,
622 AVFilterPad *newpad);
624 /** Inserts a new input pad for the filter. */
625 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
628 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
629 &f->input_pads, &f->inputs, p);
632 /** Inserts a new output pad for the filter. */
633 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
636 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
637 &f->output_pads, &f->outputs, p);
640 #endif /* AVFILTER_AVFILTER_H */