3 * copyright (c) 2007 Bobby Bingham
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #ifndef FFMPEG_AVFILTER_H
23 #define FFMPEG_AVFILTER_H
25 #define LIBAVFILTER_VERSION 0.0.0
30 typedef struct AVFilterContext AVFilterContext
;
31 typedef struct AVFilterLink AVFilterLink
;
32 typedef struct AVFilterPad AVFilterPad
;
34 /* TODO: look for other flags which may be useful in this structure (interlace
38 * A reference-counted picture data type used by the filter system. Filters
39 * should not store pointers to this structure directly, but instead use the
40 * AVFilterPicRef structure below.
42 typedef struct AVFilterPic
44 uint8_t *data
[4]; ///< picture data for each plane
45 int linesize
[4]; ///< number of bytes per line
46 enum PixelFormat format
; ///< colorspace
48 unsigned refcount
; ///< number of references to this image
50 /** private data to be used by a custom free function */
53 * A pointer to the function to deallocate this image if the default
54 * function is not sufficient. This could, for example, add the memory
55 * back into a memory pool to be reused later without the overhead of
56 * reallocating it from scratch.
58 void (*free
)(struct AVFilterPic
*pic
);
62 * A reference to an AVFilterPic. Since filters can manipulate the origin of
63 * a picture to, for example, crop image without any memcpy, the picture origin
64 * and dimensions are per-reference properties. Linesize is also useful for
65 * image flipping, frame to field filters, etc, and so is also per-reference.
67 * TODO: add anything necessary for frame reordering
69 typedef struct AVFilterPicRef
71 AVFilterPic
*pic
; ///< the picture that this is a reference to
72 uint8_t *data
[4]; ///< picture data for each plane
73 int linesize
[4]; ///< number of bytes per line
74 int w
; ///< image width
75 int h
; ///< image height
77 int64_t pts
; ///< presentation timestamp in units of 1/AV_TIME_BASE
79 AVRational pixel_aspect
; ///< pixel aspect ratio
81 int perms
; ///< permissions
82 #define AV_PERM_READ 0x01 ///< can read from the buffer
83 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
84 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
85 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
86 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
90 * Add a new reference to a picture.
91 * @param ref an existing reference to the picture
92 * @param pmask a bitmask containing the allowable permissions in the new
94 * @return a new reference to the picture with the same properties as the
95 * old, excluding any permissions denied by pmask
97 AVFilterPicRef
*avfilter_ref_pic(AVFilterPicRef
*ref
, int pmask
);
100 * Remove a reference to a picture. If this is the last reference to the
101 * picture, the picture itself is also automatically freed.
102 * @param ref reference to the picture
104 void avfilter_unref_pic(AVFilterPicRef
*ref
);
107 * A list of supported formats for one end of a filter link. This is used
108 * during the format negotiation process to try to pick the best format to
109 * use to minimize the number of necessary conversions. Each filter gives a
110 * list of the formats supported by each input and output pad. The list
111 * given for each pad need not be distinct - they may be references to the
112 * same list of formats, as is often the case when a filter supports multiple
113 * formats, but will always outut the same format as it is given in input.
115 * In this way, a list of possible input formats and a list of possible
116 * output formats are associated with each link. When a set of formats is
117 * negotiated over a link, the input and output lists are merged to form a
118 * new list containing only the common elements of each list. In the case
119 * that there were no common elements, a format conversion is necessary.
120 * Otherwise, the lists are merged, and all other links which reference
121 * either of the format lists involved in the merge are also affected.
123 * For example, consider the filter chain:
124 * filter (a) --> (b) filter (b) --> (c) filter
126 * where the letters in parenthesis indicate a list of formats supported on
127 * the input or output of the link. Suppose the lists are as follows:
132 * First, the first link's lists are merged, yielding:
133 * filter (a) --> (a) filter (a) --> (c) filter
135 * Notice that format list (b) now refers to the same list as filter list (a).
136 * Next, the lists for the second link are merged, yielding:
137 * filter (a) --> (a) filter (a) --> (a) filter
141 * Unfortunately, when the format lists at the two ends of a link are merged,
142 * we must ensure that all links which reference either pre-merge format list
143 * get updated as well. Therefore, we have the format list structure store a
144 * pointer to each of the pointers to itself.
146 typedef struct AVFilterFormats AVFilterFormats
;
147 struct AVFilterFormats
149 unsigned format_count
; ///< number of formats
150 int *formats
; ///< list of formats
152 unsigned refcount
; ///< number of references to this list
153 AVFilterFormats
***refs
; ///< references to this list
157 * Helper function to create a list of supported formats. This is intended
158 * for use in AVFilter->query_formats().
159 * @param len the number of formats supported
160 * @param ... a list of the supported formats
161 * @return the format list, with no existing references
163 AVFilterFormats
*avfilter_make_format_list(int len
, ...);
166 * Returns a list of all colorspaces supported by FFmpeg.
168 AVFilterFormats
*avfilter_all_colorspaces(void);
171 * If a and b share at least one common format, they are merged into a new
172 * format list which is returned. All the references to a and b are updated
173 * to point to this new list, and a and b are deallocated.
175 * If a and b do not share any common formats, neither is modified, and NULL
178 AVFilterFormats
*avfilter_merge_formats(AVFilterFormats
*a
, AVFilterFormats
*b
);
180 /** Adds *ref as a new reference to f */
181 void avfilter_formats_ref(AVFilterFormats
*f
, AVFilterFormats
**ref
);
184 * Remove *ref as a reference to the format list it currently points to,
185 * deallocate that list if this was the last reference, and set *ref to NULL.
187 void avfilter_formats_unref(AVFilterFormats
**ref
);
190 * A filter pad used for either input or output.
195 * Pad name. The name is unique among inputs and among outputs, but an
196 * input may have the same name as an output. This may be NULL if this
197 * pad has no need to ever be referenced by name.
202 * AVFilterPad type. Only video supported now, hopefully someone will
203 * add audio in the future.
208 * Minimum required permissions on incoming buffers. Any buffers with
209 * insufficient permissions will be automatically copied by the filter
210 * system to a new buffer which provides the needed access permissions.
217 * Permissions which are not accepted on incoming buffers. Any buffer
218 * which has any of these permissions set be automatically copied by the
219 * filter system to a new buffer which does not have those permissions.
220 * This can be used to easily disallow buffers with AV_PERM_REUSE.
227 * Callback called before passing the first slice of a new frame. If
228 * NULL, the filter layer will default to storing a reference to the
229 * picture inside the link structure.
231 * Input video pads only.
233 void (*start_frame
)(AVFilterLink
*link
, AVFilterPicRef
*picref
);
236 * Callback function to get a buffer. If NULL, the filter system will
237 * handle buffer requests.
239 * Input video pads only.
241 AVFilterPicRef
*(*get_video_buffer
)(AVFilterLink
*link
, int perms
);
244 * Callback called after the slices of a frame are completely sent. If
245 * NULL, the filter layer will default to releasing the reference stored
246 * in the link structure during start_frame().
248 * Input video pads only.
250 void (*end_frame
)(AVFilterLink
*link
);
253 * Slice drawing callback. This is where a filter receives video data
254 * and should do its processing.
256 * Input video pads only.
258 void (*draw_slice
)(AVFilterLink
*link
, int y
, int height
);
261 * Frame poll callback. This returns the number of immediately available
262 * frames. It should return a positive value if the next request_frame()
263 * is guaranteed to return one frame (with no delay).
265 * Defaults to just calling the source poll_frame() method.
267 * Output video pads only.
269 int (*poll_frame
)(AVFilterLink
*link
);
272 * Frame request callback. A call to this should result in at least one
273 * frame being output over the given link. This should return zero on
274 * success, and another value on error.
276 * Output video pads only.
278 int (*request_frame
)(AVFilterLink
*link
);
281 * Link configuration callback.
283 * For output pads, this should set the link properties such as
284 * width/height. This should NOT set the format property - that is
285 * negotiated between filters by the filter system using the
286 * query_formats() callback before this function is called.
288 * For input pads, this should check the properties of the link, and update
289 * the filter's internal state as necessary.
291 * For both input and output filters, this should return zero on success,
292 * and another value on error.
294 int (*config_props
)(AVFilterLink
*link
);
297 /** Default handler for start_frame() for video inputs */
298 void avfilter_default_start_frame(AVFilterLink
*link
, AVFilterPicRef
*picref
);
299 /** Default handler for end_frame() for video inputs */
300 void avfilter_default_end_frame(AVFilterLink
*link
);
301 /** Default handler for config_props() for video outputs */
302 int avfilter_default_config_output_link(AVFilterLink
*link
);
303 /** Default handler for config_props() for video inputs */
304 int avfilter_default_config_input_link (AVFilterLink
*link
);
305 /** Default handler for get_video_buffer() for video inputs */
306 AVFilterPicRef
*avfilter_default_get_video_buffer(AVFilterLink
*link
,
309 * A helper for query_formats() which sets all links to the same list of
310 * formats. If there are no links hooked to this filter, the list of formats is
313 void avfilter_set_common_formats(AVFilterContext
*ctx
, AVFilterFormats
*formats
);
314 /** Default handler for query_formats() */
315 int avfilter_default_query_formats(AVFilterContext
*ctx
);
317 void avfilter_formats_changeref(AVFilterFormats
**oldref
,
318 AVFilterFormats
**newref
);
321 * Filter definition. This defines the pads a filter contains, and all the
322 * callback functions used to interact with the filter.
326 const char *name
; ///< filter name
328 int priv_size
; ///< size of private data to allocate for the filter
331 * Filter initialization function. Args contains the user-supplied
332 * parameters. FIXME: maybe an AVOption-based system would be better?
333 * opaque is data provided by the code requesting creation of the filter,
334 * and is used to pass data to the filter.
336 int (*init
)(AVFilterContext
*ctx
, const char *args
, void *opaque
);
339 * Filter uninitialization function. Should deallocate any memory held
340 * by the filter, release any picture references, etc. This does not need
341 * to deallocate the AVFilterContext->priv memory itself.
343 void (*uninit
)(AVFilterContext
*ctx
);
346 * Query formats supported by the filter and its pads. Should set the
347 * in_formats for links connected to its output pads, and out_formats
348 * for links connected to its input pads.
350 * Should return zero on success.
352 int (*query_formats
)(AVFilterContext
*);
354 const AVFilterPad
*inputs
; ///< NULL terminated list of inputs. NULL if none
355 const AVFilterPad
*outputs
; ///< NULL terminated list of outputs. NULL if none
358 /** An instance of a filter */
359 struct AVFilterContext
361 AVClass
*av_class
; ///< needed for av_log()
363 AVFilter
*filter
; ///< the AVFilter of which this is an instance
365 char *name
; ///< name of this filter instance
367 unsigned input_count
; ///< number of input pads
368 AVFilterPad
*input_pads
; ///< array of input pads
369 AVFilterLink
**inputs
; ///< array of pointers to input links
371 unsigned output_count
; ///< number of output pads
372 AVFilterPad
*output_pads
; ///< array of output pads
373 AVFilterLink
**outputs
; ///< array of pointers to output links
375 void *priv
; ///< private data for use by the filter
379 * A link between two filters. This contains pointers to the source and
380 * destination filters between which this link exists, and the indices of
381 * the pads involved. In addition, this link also contains the parameters
382 * which have been negotiated and agreed upon between the filter, such as
383 * image dimensions, format, etc
387 AVFilterContext
*src
; ///< source filter
388 unsigned int srcpad
; ///< index of the output pad on the source filter
390 AVFilterContext
*dst
; ///< dest filter
391 unsigned int dstpad
; ///< index of the input pad on the dest filter
393 /** stage of the initialization of the link properties (dimensions, etc) */
395 AVLINK_UNINIT
= 0, ///< not started
396 AVLINK_STARTINIT
, ///< started, but incomplete
397 AVLINK_INIT
///< complete
400 int w
; ///< agreed upon image width
401 int h
; ///< agreed upon image height
402 enum PixelFormat format
; ///< agreed upon image colorspace
405 * Lists of formats supported by the input and output filters respectively.
406 * These lists are used for negotiating the format to actually be used,
407 * which will be loaded into the format member, above, when chosen.
409 AVFilterFormats
*in_formats
;
410 AVFilterFormats
*out_formats
;
413 * The picture reference currently being sent across the link by the source
414 * filter. This is used internally by the filter system to allow
415 * automatic copying of pictures which do not have sufficient permissions
416 * for the destination. This should not be accessed directly by the
419 AVFilterPicRef
*srcpic
;
421 AVFilterPicRef
*cur_pic
;
422 AVFilterPicRef
*outpic
;
426 * Link two filters together.
427 * @param src the source filter
428 * @param srcpad index of the output pad on the source filter
429 * @param dst the destination filter
430 * @param dstpad index of the input pad on the destination filter
431 * @return zero on success
433 int avfilter_link(AVFilterContext
*src
, unsigned srcpad
,
434 AVFilterContext
*dst
, unsigned dstpad
);
437 * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
438 * @param filter the filter to negotiate the properties for its inputs
439 * @return zero on successful negotiation
441 int avfilter_config_links(AVFilterContext
*filter
);
444 * Request a picture buffer with a specific set of permissions
445 * @param link the output link to the filter from which the picture will
447 * @param perms the required access permissions
448 * @return A reference to the picture. This must be unreferenced with
449 * avfilter_unref_pic when you are finished with it.
451 AVFilterPicRef
*avfilter_get_video_buffer(AVFilterLink
*link
, int perms
);
454 * Request an input frame from the filter at the other end of the link.
455 * @param link the input link
456 * @return zero on success
458 int avfilter_request_frame(AVFilterLink
*link
);
461 * Poll a frame from the filter chain.
462 * @param link the input link
463 * @return the number of imediately available frames
465 int avfilter_poll_frame(AVFilterLink
*link
);
468 * Notify the next filter of the start of a frame.
469 * @param link the output link the frame will be sent over
470 * @param picref A reference to the frame about to be sent. The data for this
471 * frame need only be valid once draw_slice() is called for that
472 * portion. The receiving filter will free this reference when
473 * it no longer needs it.
475 void avfilter_start_frame(AVFilterLink
*link
, AVFilterPicRef
*picref
);
478 * Notify the next filter that the current frame has finished
479 * @param link the output link the frame was sent over
481 void avfilter_end_frame(AVFilterLink
*link
);
484 * Send a slice to the next filter.
485 * @param link the output link over which the frame is being sent
486 * @param y offset in pixels from the top of the image for this slice
487 * @param h height of this slice in pixels
489 void avfilter_draw_slice(AVFilterLink
*link
, int y
, int h
);
491 /** Initialize the filter system. Registers all builtin filters */
492 void avfilter_register_all(void);
494 /** Uninitialize the filter system. Unregisters all filters */
495 void avfilter_uninit(void);
498 * Register a filter. This is only needed if you plan to use
499 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
500 * filter can still by instantiated with avfilter_open even if it is not
502 * @param filter the filter to register
504 void avfilter_register(AVFilter
*filter
);
507 * Gets a filter definition matching the given name.
508 * @param name the filter name to find
509 * @return the filter definition, if any matching one is registered.
510 * NULL if none found.
512 AVFilter
*avfilter_get_by_name(const char *name
);
515 * Create a filter instance.
516 * @param filter the filter to create an instance of
517 * @param inst_name Name to give to the new instance. Can be NULL for none.
518 * @return Pointer to the new instance on success. NULL on failure.
520 AVFilterContext
*avfilter_open(AVFilter
*filter
, const char *inst_name
);
523 * Initialize a filter.
524 * @param filter the filter to initialize
525 * @param args A string of parameters to use when initializing the filter.
526 * The format and meaning of this string varies by filter.
527 * @param opaque Any extra non-string data needed by the filter. The meaning
528 * of this parameter varies by filter.
529 * @return zero on success
531 int avfilter_init_filter(AVFilterContext
*filter
, const char *args
, void *opaque
);
535 * @param filter the filter to destroy
537 void avfilter_destroy(AVFilterContext
*filter
);
540 * Insert a filter in the middle of an existing link.
541 * @param link the link into which the filter should be inserted
542 * @param filt the filter to be inserted
543 * @param in the input pad on the filter to connect
544 * @param out the output pad on the filter to connect
545 * @return zero on success
547 int avfilter_insert_filter(AVFilterLink
*link
, AVFilterContext
*filt
,
548 unsigned in
, unsigned out
);
552 * @param idx Insertion point. Pad is inserted at the end if this point
553 * is beyond the end of the list of pads.
554 * @param count Pointer to the number of pads in the list
555 * @param padidx_off Offset within an AVFilterLink structure to the element
556 * to increment when inserting a new pad causes link
557 * numbering to change
558 * @param pads Pointer to the pointer to the beginning of the list of pads
559 * @param links Pointer to the pointer to the beginning of the list of links
560 * @param newpad The new pad to add. A copy is made when adding.
562 void avfilter_insert_pad(unsigned idx
, unsigned *count
, size_t padidx_off
,
563 AVFilterPad
**pads
, AVFilterLink
***links
,
564 AVFilterPad
*newpad
);
566 /** insert a new input pad for the filter */
567 static inline void avfilter_insert_inpad(AVFilterContext
*f
, unsigned index
,
570 avfilter_insert_pad(index
, &f
->input_count
, offsetof(AVFilterLink
, dstpad
),
571 &f
->input_pads
, &f
->inputs
, p
);
574 /** insert a new output pad for the filter */
575 static inline void avfilter_insert_outpad(AVFilterContext
*f
, unsigned index
,
578 avfilter_insert_pad(index
, &f
->output_count
, offsetof(AVFilterLink
, srcpad
),
579 &f
->output_pads
, &f
->outputs
, p
);
582 #endif /* FFMPEG_AVFILTER_H */