Add another "reuse" permission, to distinguish between the case where a
[libav.git] / libavfilter / avfilter.h
1 /*
2 * Filter layer
3 * copyright (c) 2007 Bobby Bingham
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 #ifndef FFMPEG_AVFILTER_H
23 #define FFMPEG_AVFILTER_H
24
25 #include <stddef.h>
26 #include "avcodec.h"
27
28 typedef struct AVFilterContext AVFilterContext;
29 typedef struct AVFilterLink AVFilterLink;
30 typedef struct AVFilterPad AVFilterPad;
31
32 /* TODO: look for other flags which may be useful in this structure (interlace
33 * flags, etc)
34 */
35 /**
36 * A reference-counted picture data type used by the filter system. Filters
37 * should not store pointers to this structure directly, but instead use the
38 * AVFilterPicRef structure below
39 */
40 typedef struct AVFilterPic
41 {
42 uint8_t *data[4]; ///< picture data for each plane
43 int linesize[4]; ///< number of bytes per line
44 enum PixelFormat format; ///< colorspace
45
46 unsigned refcount; ///< number of references to this image
47
48 /** private data to be used by a custom free function */
49 void *priv;
50 /**
51 * A pointer to the function to deallocate this image if the default
52 * function is not sufficient. This could, for example, add the memory
53 * back into a memory pool to be reused later without the overhead of
54 * reallocating it from scratch.
55 */
56 void (*free)(struct AVFilterPic *pic);
57 } AVFilterPic;
58
59 /**
60 * A reference to an AVFilterPic. Since filters can manipulate the origin of
61 * a picture to, for example, crop image without any memcpy, the picture origin
62 * and dimensions are per-reference properties. Linesize is also useful for
63 * image flipping, frame to field filters, etc, and so is also per-reference.
64 *
65 * TODO: add anything necessary for frame reordering
66 */
67 typedef struct AVFilterPicRef
68 {
69 AVFilterPic *pic; ///< the picture that this is a reference to
70 uint8_t *data[4]; ///< picture data for each plane
71 int linesize[4]; ///< number of bytes per line
72 int w; ///< image width
73 int h; ///< image height
74
75 int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE
76
77 int perms; ///< permissions
78 #define AV_PERM_READ 0x01 ///< can read from the buffer
79 #define AV_PERM_WRITE 0x02 ///< can write to the buffer
80 #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer
81 #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time
82 #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time
83 } AVFilterPicRef;
84
85 /**
86 * Add a new reference to a picture.
87 * @param ref An existing reference to the picture
88 * @param pmask A bitmask containing the allowable permissions in the new
89 * reference
90 * @return A new reference to the picture with the same properties as the
91 * old, excluding any permissions denied by pmask
92 */
93 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
94
95 /**
96 * Remove a reference to a picture. If this is the last reference to the
97 * picture, the picture itself is also automatically freed.
98 * @param ref Reference to the picture.
99 */
100 void avfilter_unref_pic(AVFilterPicRef *ref);
101
102 /**
103 * A filter pad used for either input or output
104 */
105 struct AVFilterPad
106 {
107 /**
108 * Pad name. The name is unique among inputs and among outputs, but an
109 * input may have the same name as an output. This may be NULL if this
110 * pad has no need to ever be referenced by name.
111 */
112 char *name;
113
114 /**
115 * AVFilterPad type. Only video supported now, hopefully someone will
116 * add audio in the future.
117 */
118 int type;
119 #define AV_PAD_VIDEO 0 ///< video pad
120
121 /**
122 * Minimum required permissions on incoming buffers. Any buffers with
123 * insufficient permissions will be automatically copied by the filter
124 * system to a new buffer which provides the needed access permissions.
125 *
126 * Input pads only.
127 */
128 int min_perms;
129
130 /**
131 * Permissions which are not accepted on incoming buffers. Any buffer
132 * which has any of these permissions set be automatically copied by the
133 * filter system to a new buffer which does not have those permissions.
134 * This can be used to easily disallow buffers with AV_PERM_REUSE.
135 *
136 * Input pads only.
137 */
138 int rej_perms;
139
140 /**
141 * Callback to get a list of supported formats. The returned list should
142 * be terminated by -1 (see avfilter_make_format_list for an easy way to
143 * create such a list).
144 *
145 * This is used for both input and output pads. If ommitted from an output
146 * pad, it is assumed that the only format supported is the same format
147 * that is being used for the filter's first input. If the filter has no
148 * inputs, then this may not be ommitted for its output pads.
149 */
150 int *(*query_formats)(AVFilterLink *link);
151
152 /**
153 * Callback called before passing the first slice of a new frame. If
154 * NULL, the filter layer will default to storing a reference to the
155 * picture inside the link structure.
156 *
157 * Input video pads only.
158 */
159 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
160
161 /**
162 * Callback function to get a buffer. If NULL, the filter system will
163 * handle buffer requests.
164 *
165 * Input video pads only.
166 */
167 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
168
169 /**
170 * Callback called after the slices of a frame are completely sent. If
171 * NULL, the filter layer will default to releasing the reference stored
172 * in the link structure during start_frame().
173 *
174 * Input video pads only.
175 */
176 void (*end_frame)(AVFilterLink *link);
177
178 /**
179 * Slice drawing callback. This is where a filter receives video data
180 * and should do its processing.
181 *
182 * Input video pads only.
183 */
184 void (*draw_slice)(AVFilterLink *link, int y, int height);
185
186 /**
187 * Frame request callback. A call to this should result in at least one
188 * frame being output over the given link. This should return zero on
189 * success, and another value on error.
190 *
191 * Output video pads only.
192 */
193 int (*request_frame)(AVFilterLink *link);
194
195 /**
196 * Link configuration callback.
197 *
198 * For output pads, this should set the link properties such as
199 * width/height. This should NOT set the format property - that is
200 * negotiated between filters by the filter system using the
201 * query_formats() callback before this function is called.
202 *
203 * For input pads, this should check the properties of the link, and update
204 * the filter's internal state as necessary.
205 *
206 * For both input and output filters, this should return zero on success,
207 * and another value on error.
208 */
209 int (*config_props)(AVFilterLink *link);
210 };
211
212 /** Default handler for start_frame() for video inputs */
213 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
214 /** Default handler for end_frame() for video inputs */
215 void avfilter_default_end_frame(AVFilterLink *link);
216 /** Default handler for config_props() for video outputs */
217 int avfilter_default_config_output_link(AVFilterLink *link);
218 /** Default handler for config_props() for video inputs */
219 int avfilter_default_config_input_link (AVFilterLink *link);
220 /** Default handler for query_formats() for video outputs */
221 int *avfilter_default_query_output_formats(AVFilterLink *link);
222 /** Default handler for get_video_buffer() for video inputs */
223 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
224 int perms);
225
226 /**
227 * Filter definition. This defines the pads a filter contains, and all the
228 * callback functions used to interact with the filter.
229 */
230 typedef struct
231 {
232 char *name; ///< filter name
233 char *author; ///< filter author
234
235 int priv_size; ///< size of private data to allocate for the filter
236
237 /**
238 * Filter initialization function. Args contains the user-supplied
239 * parameters. FIXME: maybe an AVOption-based system would be better?
240 * opaque is data provided by the code requesting creation of the filter,
241 * and is used to pass data to the filter.
242 */
243 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
244
245 /**
246 * Filter uninitialization function. Should deallocate any memory held
247 * by the filter, release any picture references, etc. This does not need
248 * to deallocate the AVFilterContext->priv memory itself.
249 */
250 void (*uninit)(AVFilterContext *ctx);
251
252 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
253 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
254 } AVFilter;
255
256 /** An instance of a filter */
257 struct AVFilterContext
258 {
259 AVClass *av_class; ///< Needed for av_log()
260
261 AVFilter *filter; ///< The AVFilter of which this is an instance
262
263 char *name; ///< name of this filter instance
264
265 unsigned input_count; ///< number of input pads
266 AVFilterPad *input_pads; ///< array of input pads
267 AVFilterLink **inputs; ///< array of pointers to input links
268
269 unsigned output_count; ///< number of output pads
270 AVFilterPad *output_pads; ///< array of output pads
271 AVFilterLink **outputs; ///< array of pointers to output links
272
273 void *priv; ///< private data for use by the filter
274 };
275
276 /**
277 * A links between two filters. This contains pointers to the source and
278 * destination filters between which this link exists, and the indices of
279 * the pads involved. In addition, this link also contains the parameters
280 * which have been negotiated and agreed upon between the filter, such as
281 * image dimensions, format, etc
282 */
283 struct AVFilterLink
284 {
285 AVFilterContext *src; ///< source filter
286 unsigned int srcpad; ///< index of the output pad on the source filter
287
288 AVFilterContext *dst; ///< dest filter
289 unsigned int dstpad; ///< index of the input pad on the dest filter
290
291 int w; ///< agreed upon image width
292 int h; ///< agreed upon image height
293 enum PixelFormat format; ///< agreed upon image colorspace
294
295 /**
296 * The picture reference currently being sent across the link by the source
297 * filter. This is used internally by the filter system to allow
298 * automatic copying of pictures which d not have sufficient permissions
299 * for the destination. This should not be accessed directly by the
300 * filters.
301 */
302 AVFilterPicRef *srcpic;
303
304 AVFilterPicRef *cur_pic;
305 AVFilterPicRef *outpic;
306 };
307
308 /**
309 * Link two filters together
310 * @param src The source filter
311 * @param srcpad Index of the output pad on the source filter
312 * @param dst The destination filter
313 * @param dstpad Index of the input pad on the destination filter
314 * @return Zero on success
315 */
316 int avfilter_link(AVFilterContext *src, unsigned srcpad,
317 AVFilterContext *dst, unsigned dstpad);
318
319 /**
320 * Negotiate the colorspace, dimensions, etc of a link
321 * @param link The link to negotiate the properties of
322 * @return Zero on successful negotiation
323 */
324 int avfilter_config_link(AVFilterLink *link);
325
326 /**
327 * Request a picture buffer with a specific set of permissions
328 * @param link The output link to the filter from which the picture will
329 * be requested
330 * @param perms The required access permissions
331 * @return A reference to the picture. This must be unreferenced with
332 * avfilter_unref_pic when you are finished with it.
333 */
334 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
335
336 /**
337 * Request an input frame from the filter at the other end of the link.
338 * @param link The input link
339 * @return Zero on success
340 */
341 int avfilter_request_frame(AVFilterLink *link);
342
343 /**
344 * Notify the next filter of the start of a frame.
345 * @param link The output link the frame will be sent over
346 * @param picref A reference to the frame about to be sent. The data for this
347 * frame need only be valid once draw_slice() is called for that
348 * portion. The receiving filter will free this reference when
349 * it no longer needs it.
350 */
351 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
352
353 /**
354 * Notify the next filter that the current frame has finished
355 * @param link The output link the frame was sent over
356 */
357 void avfilter_end_frame(AVFilterLink *link);
358
359 /**
360 * Send a slice to the next filter
361 * @param link The output link over which the frame is being sent
362 * @param y Offset in pixels from the top of the image for this slice
363 * @param h Height of this slice in pixels
364 */
365 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
366
367 /** Initialize the filter system. Registers all builtin filters */
368 void avfilter_init(void);
369
370 /** Uninitialize the filter system. Unregisters all filters */
371 void avfilter_uninit(void);
372
373 /**
374 * Register a filter. This is only needed if you plan to use
375 * avfilter_get_by_name later to lookup the AVFilter structure by name. A
376 * filter can still by instantiated with avfilter_open even if it is not
377 * registered.
378 * @param filter The filter to register
379 */
380 void avfilter_register(AVFilter *filter);
381
382 /**
383 * Gets a filter definition matching the given name
384 * @param name The filter name to find
385 * @return The filter definition, if any matching one is registered.
386 * NULL if none found.
387 */
388 AVFilter *avfilter_get_by_name(char *name);
389
390 /**
391 * Create a filter instance
392 * @param filter The filter to create an instance of
393 * @param inst_name Name to give to the new instance. Can be NULL for none.
394 * @return Pointer to the new instance on success. NULL on failure.
395 */
396 AVFilterContext *avfilter_open(AVFilter *filter, char *inst_name);
397
398 /**
399 * Initialize a filter
400 * @param filter The filter to initialize
401 * @param args A string of parameters to use when initializing the filter.
402 * The format and meaning of this string varies by filter.
403 * @param opaque Any extra non-string data needed by the filter. The meaning
404 * of this parameter varies by filter.
405 * @return Zero on success
406 */
407 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
408
409 /**
410 * Destroy a filter
411 * @param filter The filter to destroy
412 */
413 void avfilter_destroy(AVFilterContext *filter);
414
415 /**
416 * Helper function to create a list of supported formats. This is intended
417 * for use in AVFilterPad->query_formats().
418 * @param len The number of formats supported
419 * @param ... A list of the supported formats
420 * @return The format list in a form suitable for returning from
421 * AVFilterPad->query_formats()
422 */
423 int *avfilter_make_format_list(int len, ...);
424
425 /**
426 * Insert a new pad
427 * @param idx Insertion point. Pad is inserted at the end if this point
428 * is beyond the end of the list of pads.
429 * @param count Pointer to the number of pads in the list
430 * @param padidx_off Offset within an AVFilterLink structure to the element
431 * to increment when inserting a new pad causes link
432 * numbering to change
433 * @param pads Pointer to the pointer to the beginning of the list of pads
434 * @param links Pointer to the pointer to the beginning of the list of links
435 * @param newpad The new pad to add. A copy is made when adding.
436 */
437 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
438 AVFilterPad **pads, AVFilterLink ***links,
439 AVFilterPad *newpad);
440
441 /** insert a new input pad for the filter */
442 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
443 AVFilterPad *p)
444 {
445 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
446 &f->input_pads, &f->inputs, p);
447 }
448
449 /** insert a new output pad for the filter */
450 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
451 AVFilterPad *p)
452 {
453 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
454 &f->output_pads, &f->outputs, p);
455 }
456
457 #endif /* FFMPEG_AVFILTER_H */