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 33
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 * 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;
63 * A reference-counted buffer data type used by the filter system. Filters
64 * should not store pointers to this structure directly, but instead use the
65 * AVFilterBufferRef structure below.
67 typedef struct AVFilterBuffer
69 uint8_t *data[8]; ///< buffer data for each plane/channel
70 int linesize[8]; ///< number of bytes per line
72 unsigned refcount; ///< number of references to this buffer
74 /** private data to be used by a custom free function */
77 * A pointer to the function to deallocate this buffer if the default
78 * function is not sufficient. This could, for example, add the memory
79 * back into a memory pool to be reused later without the overhead of
80 * reallocating it from scratch.
82 void (*free)(struct AVFilterBuffer *buf);
85 #define AV_PERM_READ 0x01 ///< can read from the buffer
86 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
87 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
88 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
89 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
92 * Video specific properties in a reference to an AVFilterBuffer. Since
93 * AVFilterBufferRef is common to different media formats, video specific
94 * per reference properties must be separated out.
96 typedef struct AVFilterBufferRefVideoProps
98 int w; ///< image width
99 int h; ///< image height
100 AVRational pixel_aspect; ///< pixel aspect ratio
101 int interlaced; ///< is frame interlaced
102 int top_field_first; ///< field order
103 } AVFilterBufferRefVideoProps;
106 * A reference to an AVFilterBuffer. Since filters can manipulate the origin of
107 * a buffer to, for example, crop image without any memcpy, the buffer origin
108 * and dimensions are per-reference properties. Linesize is also useful for
109 * image flipping, frame to field filters, etc, and so is also per-reference.
111 * TODO: add anything necessary for frame reordering
113 typedef struct AVFilterBufferRef
115 AVFilterBuffer *buf; ///< the buffer that this is a reference to
116 uint8_t *data[4]; ///< picture data for each plane
117 int linesize[4]; ///< number of bytes per line
118 int format; ///< media format
120 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
121 int64_t pos; ///< byte position in stream, -1 if unknown
123 int perms; ///< permissions, see the AV_PERM_* flags
125 enum AVMediaType type; ///< media type of buffer data
126 AVFilterBufferRefVideoProps *video; ///< video buffer specific properties
130 * Copy properties of src to dst, without copying the actual video
133 static inline void avfilter_copy_buffer_ref_props(AVFilterBufferRef *dst, AVFilterBufferRef *src)
135 // copy common properties
140 case AVMEDIA_TYPE_VIDEO: *dst->video = *src->video; break;
145 * Add a new reference to a buffer.
146 * @param ref an existing reference to the buffer
147 * @param pmask a bitmask containing the allowable permissions in the new
149 * @return a new reference to the buffer with the same properties as the
150 * old, excluding any permissions denied by pmask
152 AVFilterBufferRef *avfilter_ref_buffer(AVFilterBufferRef *ref, int pmask);
155 * Remove a reference to a buffer. If this is the last reference to the
156 * buffer, the buffer itself is also automatically freed.
157 * @param ref reference to the buffer
159 void avfilter_unref_buffer(AVFilterBufferRef *ref);
162 * A list of supported formats for one end of a filter link. This is used
163 * during the format negotiation process to try to pick the best format to
164 * use to minimize the number of necessary conversions. Each filter gives a
165 * list of the formats supported by each input and output pad. The list
166 * given for each pad need not be distinct - they may be references to the
167 * same list of formats, as is often the case when a filter supports multiple
168 * formats, but will always output the same format as it is given in input.
170 * In this way, a list of possible input formats and a list of possible
171 * output formats are associated with each link. When a set of formats is
172 * negotiated over a link, the input and output lists are merged to form a
173 * new list containing only the common elements of each list. In the case
174 * that there were no common elements, a format conversion is necessary.
175 * Otherwise, the lists are merged, and all other links which reference
176 * either of the format lists involved in the merge are also affected.
178 * For example, consider the filter chain:
179 * filter (a) --> (b) filter (b) --> (c) filter
181 * where the letters in parenthesis indicate a list of formats supported on
182 * the input or output of the link. Suppose the lists are as follows:
187 * First, the first link's lists are merged, yielding:
188 * filter (a) --> (a) filter (a) --> (c) filter
190 * Notice that format list (b) now refers to the same list as filter list (a).
191 * Next, the lists for the second link are merged, yielding:
192 * filter (a) --> (a) filter (a) --> (a) filter
196 * Unfortunately, when the format lists at the two ends of a link are merged,
197 * we must ensure that all links which reference either pre-merge format list
198 * get updated as well. Therefore, we have the format list structure store a
199 * pointer to each of the pointers to itself.
201 typedef struct AVFilterFormats AVFilterFormats;
202 struct AVFilterFormats
204 unsigned format_count; ///< number of formats
205 int *formats; ///< list of media formats
207 unsigned refcount; ///< number of references to this list
208 AVFilterFormats ***refs; ///< references to this list
212 * Create a list of supported formats. This is intended for use in
213 * AVFilter->query_formats().
214 * @param fmts list of media formats, terminated by -1
215 * @return the format list, with no existing references
217 AVFilterFormats *avfilter_make_format_list(const int *fmts);
220 * Add fmt to the list of media formats contained in *avff.
221 * If *avff is NULL the function allocates the filter formats struct
222 * and puts its pointer in *avff.
224 * @return a non negative value in case of success, or a negative
225 * value corresponding to an AVERROR code in case of error
227 int avfilter_add_format(AVFilterFormats **avff, int fmt);
230 * Return a list of all formats supported by FFmpeg for the given media type.
232 AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
235 * Return a format list which contains the intersection of the formats of
236 * a and b. Also, all the references of a, all the references of b, and
237 * a and b themselves will be deallocated.
239 * If a and b do not share any common formats, neither is modified, and NULL
242 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
245 * Add *ref as a new reference to formats.
246 * That is the pointers will point like in the ascii art below:
248 * |formats |<--------.
249 * | ____ | ____|___________________
251 * | |* * | | | | | | AVFilterLink
252 * | |* *--------->|*ref|
253 * | |____| | | |____|
254 * |________| |________________________
256 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
259 * If *ref is non-NULL, remove *ref as a reference to the format list
260 * it currently points to, deallocates that list if this was the last
261 * reference, and sets *ref to NULL.
264 * ________ ________ NULL
265 * |formats |<--------. |formats | ^
266 * | ____ | ____|________________ | ____ | ____|________________
267 * | |refs| | | __|_ | |refs| | | __|_
268 * | |* * | | | | | | AVFilterLink | |* * | | | | | | AVFilterLink
269 * | |* *--------->|*ref| | |* | | | |*ref|
270 * | |____| | | |____| | |____| | | |____|
271 * |________| |_____________________ |________| |_____________________
273 void avfilter_formats_unref(AVFilterFormats **ref);
279 * |formats |<---------. |formats |<---------.
280 * | ____ | ___|___ | ____ | ___|___
281 * | |refs| | | | | | |refs| | | | | NULL
282 * | |* *--------->|*oldref| | |* *--------->|*newref| ^
283 * | |* * | | |_______| | |* * | | |_______| ___|___
284 * | |____| | | |____| | | | |
285 * |________| |________| |*oldref|
288 void avfilter_formats_changeref(AVFilterFormats **oldref,
289 AVFilterFormats **newref);
292 * A filter pad used for either input or output.
297 * Pad name. The name is unique among inputs and among outputs, but an
298 * input may have the same name as an output. This may be NULL if this
299 * pad has no need to ever be referenced by name.
304 * AVFilterPad type. Only video supported now, hopefully someone will
305 * add audio in the future.
307 enum AVMediaType type;
310 * Minimum required permissions on incoming buffers. Any buffer with
311 * insufficient permissions will be automatically copied by the filter
312 * system to a new buffer which provides the needed access permissions.
319 * Permissions which are not accepted on incoming buffers. Any buffer
320 * which has any of these permissions set will be automatically copied
321 * by the filter system to a new buffer which does not have those
322 * permissions. This can be used to easily disallow buffers with
330 * Callback called before passing the first slice of a new frame. If
331 * NULL, the filter layer will default to storing a reference to the
332 * picture inside the link structure.
334 * Input video pads only.
336 void (*start_frame)(AVFilterLink *link, AVFilterBufferRef *picref);
339 * Callback function to get a buffer. If NULL, the filter system will
340 * use avfilter_default_get_video_buffer().
342 * Input video pads only.
344 AVFilterBufferRef *(*get_video_buffer)(AVFilterLink *link, int perms, int w, int h);
347 * Callback called after the slices of a frame are completely sent. If
348 * NULL, the filter layer will default to releasing the reference stored
349 * in the link structure during start_frame().
351 * Input video pads only.
353 void (*end_frame)(AVFilterLink *link);
356 * Slice drawing callback. This is where a filter receives video data
357 * and should do its processing.
359 * Input video pads only.
361 void (*draw_slice)(AVFilterLink *link, int y, int height, int slice_dir);
364 * Frame poll callback. This returns the number of immediately available
365 * frames. It should return a positive value if the next request_frame()
366 * is guaranteed to return one frame (with no delay).
368 * Defaults to just calling the source poll_frame() method.
370 * Output video pads only.
372 int (*poll_frame)(AVFilterLink *link);
375 * Frame request callback. A call to this should result in at least one
376 * frame being output over the given link. This should return zero on
377 * success, and another value on error.
379 * Output video pads only.
381 int (*request_frame)(AVFilterLink *link);
384 * Link configuration callback.
386 * For output pads, this should set the link properties such as
387 * width/height. This should NOT set the format property - that is
388 * negotiated between filters by the filter system using the
389 * query_formats() callback before this function is called.
391 * For input pads, this should check the properties of the link, and update
392 * the filter's internal state as necessary.
394 * For both input and output filters, this should return zero on success,
395 * and another value on error.
397 int (*config_props)(AVFilterLink *link);
400 /** default handler for start_frame() for video inputs */
401 void avfilter_default_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
402 /** default handler for draw_slice() for video inputs */
403 void avfilter_default_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
404 /** default handler for end_frame() for video inputs */
405 void avfilter_default_end_frame(AVFilterLink *link);
406 /** default handler for config_props() for video outputs */
407 int avfilter_default_config_output_link(AVFilterLink *link);
408 /** default handler for config_props() for video inputs */
409 int avfilter_default_config_input_link (AVFilterLink *link);
410 /** default handler for get_video_buffer() for video inputs */
411 AVFilterBufferRef *avfilter_default_get_video_buffer(AVFilterLink *link,
412 int perms, int w, int h);
414 * A helper for query_formats() which sets all links to the same list of
415 * formats. If there are no links hooked to this filter, the list of formats is
418 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
419 /** Default handler for query_formats() */
420 int avfilter_default_query_formats(AVFilterContext *ctx);
422 /** start_frame() handler for filters which simply pass video along */
423 void avfilter_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
425 /** draw_slice() handler for filters which simply pass video along */
426 void avfilter_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
428 /** end_frame() handler for filters which simply pass video along */
429 void avfilter_null_end_frame(AVFilterLink *link);
431 /** get_video_buffer() handler for filters which simply pass video along */
432 AVFilterBufferRef *avfilter_null_get_video_buffer(AVFilterLink *link,
433 int perms, int w, int h);
436 * Filter definition. This defines the pads a filter contains, and all the
437 * callback functions used to interact with the filter.
439 typedef struct AVFilter
441 const char *name; ///< filter name
443 int priv_size; ///< size of private data to allocate for the filter
446 * Filter initialization function. Args contains the user-supplied
447 * parameters. FIXME: maybe an AVOption-based system would be better?
448 * opaque is data provided by the code requesting creation of the filter,
449 * and is used to pass data to the filter.
451 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
454 * Filter uninitialization function. Should deallocate any memory held
455 * by the filter, release any buffer references, etc. This does not need
456 * to deallocate the AVFilterContext->priv memory itself.
458 void (*uninit)(AVFilterContext *ctx);
461 * Queries formats supported by the filter and its pads, and sets the
462 * in_formats for links connected to its output pads, and out_formats
463 * for links connected to its input pads.
465 * @return zero on success, a negative value corresponding to an
466 * AVERROR code otherwise
468 int (*query_formats)(AVFilterContext *);
470 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
471 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
474 * A description for the filter. You should use the
475 * NULL_IF_CONFIG_SMALL() macro to define it.
477 const char *description;
480 /** An instance of a filter */
481 struct AVFilterContext
483 const AVClass *av_class; ///< needed for av_log()
485 AVFilter *filter; ///< the AVFilter of which this is an instance
487 char *name; ///< name of this filter instance
489 unsigned input_count; ///< number of input pads
490 AVFilterPad *input_pads; ///< array of input pads
491 AVFilterLink **inputs; ///< array of pointers to input links
493 unsigned output_count; ///< number of output pads
494 AVFilterPad *output_pads; ///< array of output pads
495 AVFilterLink **outputs; ///< array of pointers to output links
497 void *priv; ///< private data for use by the filter
501 * A link between two filters. This contains pointers to the source and
502 * destination filters between which this link exists, and the indexes of
503 * the pads involved. In addition, this link also contains the parameters
504 * which have been negotiated and agreed upon between the filter, such as
505 * image dimensions, format, etc.
509 AVFilterContext *src; ///< source filter
510 unsigned int srcpad; ///< index of the output pad on the source filter
512 AVFilterContext *dst; ///< dest filter
513 unsigned int dstpad; ///< index of the input pad on the dest filter
515 /** stage of the initialization of the link properties (dimensions, etc) */
517 AVLINK_UNINIT = 0, ///< not started
518 AVLINK_STARTINIT, ///< started, but incomplete
519 AVLINK_INIT ///< complete
522 enum AVMediaType type; ///< filter media type
524 int w; ///< agreed upon image width
525 int h; ///< agreed upon image height
526 int format; ///< agreed upon media format
529 * Lists of formats supported by the input and output filters respectively.
530 * These lists are used for negotiating the format to actually be used,
531 * which will be loaded into the format member, above, when chosen.
533 AVFilterFormats *in_formats;
534 AVFilterFormats *out_formats;
537 * The buffer reference currently being sent across the link by the source
538 * filter. This is used internally by the filter system to allow
539 * automatic copying of buffers which do not have sufficient permissions
540 * for the destination. This should not be accessed directly by the
543 AVFilterBufferRef *src_buf;
545 AVFilterBufferRef *cur_buf;
546 AVFilterBufferRef *out_buf;
550 * Link two filters together.
551 * @param src the source filter
552 * @param srcpad index of the output pad on the source filter
553 * @param dst the destination filter
554 * @param dstpad index of the input pad on the destination filter
555 * @return zero on success
557 int avfilter_link(AVFilterContext *src, unsigned srcpad,
558 AVFilterContext *dst, unsigned dstpad);
561 * Negotiate the media format, dimensions, etc of all inputs to a filter.
562 * @param filter the filter to negotiate the properties for its inputs
563 * @return zero on successful negotiation
565 int avfilter_config_links(AVFilterContext *filter);
568 * Request a picture buffer with a specific set of permissions.
569 * @param link the output link to the filter from which the buffer will
571 * @param perms the required access permissions
572 * @param w the minimum width of the buffer to allocate
573 * @param h the minimum height of the buffer to allocate
574 * @return A reference to the buffer. This must be unreferenced with
575 * avfilter_unref_buffer when you are finished with it.
577 AVFilterBufferRef *avfilter_get_video_buffer(AVFilterLink *link, int perms,
581 * Request an input frame from the filter at the other end of the link.
582 * @param link the input link
583 * @return zero on success
585 int avfilter_request_frame(AVFilterLink *link);
588 * Poll a frame from the filter chain.
589 * @param link the input link
590 * @return the number of immediately available frames, a negative
591 * number in case of error
593 int avfilter_poll_frame(AVFilterLink *link);
596 * Notifie the next filter of the start of a frame.
597 * @param link the output link the frame will be sent over
598 * @param picref A reference to the frame about to be sent. The data for this
599 * frame need only be valid once draw_slice() is called for that
600 * portion. The receiving filter will free this reference when
601 * it no longer needs it.
603 void avfilter_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
606 * Notifie the next filter that the current frame has finished.
607 * @param link the output link the frame was sent over
609 void avfilter_end_frame(AVFilterLink *link);
612 * Send a slice to the next filter.
614 * Slices have to be provided in sequential order, either in
615 * top-bottom or bottom-top order. If slices are provided in
616 * non-sequential order the behavior of the function is undefined.
618 * @param link the output link over which the frame is being sent
619 * @param y offset in pixels from the top of the image for this slice
620 * @param h height of this slice in pixels
621 * @param slice_dir the assumed direction for sending slices,
622 * from the top slice to the bottom slice if the value is 1,
623 * from the bottom slice to the top slice if the value is -1,
624 * for other values the behavior of the function is undefined.
626 void avfilter_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
628 /** Initialize the filter system. Register all builtin filters. */
629 void avfilter_register_all(void);
631 /** Uninitialize the filter system. Unregister all filters. */
632 void avfilter_uninit(void);
635 * Register a filter. This is only needed if you plan to use
636 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
637 * filter can still by instantiated with avfilter_open even if it is not
639 * @param filter the filter to register
640 * @return 0 if the registration was succesfull, a negative value
643 int avfilter_register(AVFilter *filter);
646 * Get a filter definition matching the given name.
647 * @param name the filter name to find
648 * @return the filter definition, if any matching one is registered.
649 * NULL if none found.
651 AVFilter *avfilter_get_by_name(const char *name);
654 * If filter is NULL, returns a pointer to the first registered filter pointer,
655 * if filter is non-NULL, returns the next pointer after filter.
656 * If the returned pointer points to NULL, the last registered filter
657 * was already reached.
659 AVFilter **av_filter_next(AVFilter **filter);
662 * Create a filter instance.
664 * @param filter_ctx put here a pointer to the created filter context
665 * on success, NULL on failure
666 * @param filter the filter to create an instance of
667 * @param inst_name Name to give to the new instance. Can be NULL for none.
668 * @return >= 0 in case of success, a negative error code otherwise
670 int avfilter_open(AVFilterContext **filter_ctx, AVFilter *filter, const char *inst_name);
673 * Initialize a filter.
674 * @param filter the filter to initialize
675 * @param args A string of parameters to use when initializing the filter.
676 * The format and meaning of this string varies by filter.
677 * @param opaque Any extra non-string data needed by the filter. The meaning
678 * of this parameter varies by filter.
679 * @return zero on success
681 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
685 * @param filter the filter to destroy
687 void avfilter_destroy(AVFilterContext *filter);
690 * Insert a filter in the middle of an existing link.
691 * @param link the link into which the filter should be inserted
692 * @param filt the filter to be inserted
693 * @param in the input pad on the filter to connect
694 * @param out the output pad on the filter to connect
695 * @return zero on success
697 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
698 unsigned in, unsigned out);
702 * @param idx Insertion point. Pad is inserted at the end if this point
703 * is beyond the end of the list of pads.
704 * @param count Pointer to the number of pads in the list
705 * @param padidx_off Offset within an AVFilterLink structure to the element
706 * to increment when inserting a new pad causes link
707 * numbering to change
708 * @param pads Pointer to the pointer to the beginning of the list of pads
709 * @param links Pointer to the pointer to the beginning of the list of links
710 * @param newpad The new pad to add. A copy is made when adding.
712 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
713 AVFilterPad **pads, AVFilterLink ***links,
714 AVFilterPad *newpad);
716 /** Insert a new input pad for the filter. */
717 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
720 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
721 &f->input_pads, &f->inputs, p);
724 /** Insert a new output pad for the filter. */
725 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
728 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
729 &f->output_pads, &f->outputs, p);
732 #endif /* AVFILTER_AVFILTER_H */