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[libav.git] / libavfilter / avfilter.h
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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
a9c81431 25#include <stddef.h>
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26#include "avcodec.h"
27
28typedef struct AVFilterContext AVFilterContext;
29typedef struct AVFilterLink AVFilterLink;
30typedef 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 */
40typedef struct AVFilterPic
41{
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42 uint8_t *data[4]; ///< picture data for each plane
43 int linesize[4]; ///< number of bytes per line
44 enum PixelFormat format; ///< colorspace
a5cbb2f4 45
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46 unsigned refcount; ///< number of references to this image
47
48 /** private data to be used by a custom free function */
a5cbb2f4 49 void *priv;
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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 */
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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
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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.
a5cbb2f4 64 *
1a18860a 65 * TODO: add anything necessary for frame reordering
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66 */
67typedef struct AVFilterPicRef
68{
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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
a5cbb2f4 74
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75 int64_t pts; ///< presentation timestamp in milliseconds
76
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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
82} AVFilterPicRef;
83
84/**
85 * Add a new reference to a picture.
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86 * @param ref An existing reference to the picture
87 * @param pmask A bitmask containing the allowable permissions in the new
88 * reference
89 * @return A new reference to the picture with the same properties as the
90 * old, excluding any permissions denied by pmask
a5cbb2f4 91 */
8fb48e7c 92AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
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93
94/**
95 * Remove a reference to a picture. If this is the last reference to the
96 * picture, the picture itself is also automatically freed.
97 * @param ref Reference to the picture.
98 */
99void avfilter_unref_pic(AVFilterPicRef *ref);
100
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101/**
102 * A filter pad used for either input or output
103 */
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104struct AVFilterPad
105{
106 /**
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107 * Pad name. The name is unique among inputs and among outputs, but an
108 * input may have the same name as an output. This may be NULL if this
109 * pad has no need to ever be referenced by name.
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110 */
111 char *name;
112
113 /**
114 * AVFilterPad type. Only video supported now, hopefully someone will
115 * add audio in the future.
116 */
117 int type;
13ff8fd0 118#define AV_PAD_VIDEO 0 ///< video pad
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119
120 /**
d3e57c15 121 * Callback to get a list of supported formats. The returned list should
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122 * be terminated by -1 (see avfilter_make_format_list for an easy way to
123 * create such a list).
124 *
125 * This is used for both input and output pads. If ommitted from an output
126 * pad, it is assumed that the only format supported is the same format
127 * that is being used for the filter's first input. If the filter has no
128 * inputs, then this may not be ommitted for its output pads.
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129 */
130 int *(*query_formats)(AVFilterLink *link);
131
132 /**
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133 * Callback called before passing the first slice of a new frame. If
134 * NULL, the filter layer will default to storing a reference to the
135 * picture inside the link structure.
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136 *
137 * Input video pads only.
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138 */
139 void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
140
141 /**
142 * Callback function to get a buffer. If NULL, the filter system will
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143 * handle buffer requests.
144 *
145 * Input video pads only.
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146 */
147 AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
148
149 /**
150 * Callback called after the slices of a frame are completely sent. If
151 * NULL, the filter layer will default to releasing the reference stored
152 * in the link structure during start_frame().
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153 *
154 * Input video pads only.
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155 */
156 void (*end_frame)(AVFilterLink *link);
157
158 /**
159 * Slice drawing callback. This is where a filter receives video data
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160 * and should do its processing.
161 *
162 * Input video pads only.
a5cbb2f4 163 */
72f6d631 164 void (*draw_slice)(AVFilterLink *link, int y, int height);
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165
166 /**
167 * Frame request callback. A call to this should result in at least one
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168 * frame being output over the given link. This should return zero on
169 * success, and another value on error.
170 *
171 * Output video pads only.
a5cbb2f4 172 */
63f64e6f 173 int (*request_frame)(AVFilterLink *link);
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174
175 /**
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176 * Link configuration callback.
177 *
178 * For output pads, this should set the link properties such as
179 * width/height. This should NOT set the format property - that is
180 * negotiated between filters by the filter system using the
181 * query_formats() callback before this function is called.
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182 *
183 * For input pads, this should check the properties of the link, and update
184 * the filter's internal state as necessary.
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185 *
186 * For both input and output filters, this should return zero on success,
187 * and another value on error.
a5cbb2f4 188 */
d3e57c15 189 int (*config_props)(AVFilterLink *link);
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190};
191
13ff8fd0 192/** Default handler for start_frame() for video inputs */
a5cbb2f4 193void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
13ff8fd0 194/** Default handler for end_frame() for video inputs */
a5cbb2f4 195void avfilter_default_end_frame(AVFilterLink *link);
13ff8fd0 196/** Default handler for config_props() for video outputs */
901e6b39 197int avfilter_default_config_output_link(AVFilterLink *link);
13ff8fd0 198/** Default handler for config_props() for video inputs */
85322466 199int avfilter_default_config_input_link (AVFilterLink *link);
13ff8fd0 200/** Default handler for query_formats() for video outputs */
901e6b39 201int *avfilter_default_query_output_formats(AVFilterLink *link);
13ff8fd0 202/** Default handler for get_video_buffer() for video inputs */
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203AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
204 int perms);
a5cbb2f4 205
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206/**
207 * Filter definition. This defines the pads a filter contains, and all the
208 * callback functions used to interact with the filter.
209 */
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210typedef struct
211{
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212 char *name; ///< filter name
213 char *author; ///< filter author
a5cbb2f4 214
13ff8fd0 215 int priv_size; ///< size of private data to allocate for the filter
a5cbb2f4 216
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217 /**
218 * Filter initialization function. Args contains the user-supplied
219 * parameters. FIXME: maybe an AVOption-based system would be better?
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220 * opaque is data provided by the code requesting creation of the filter,
221 * and is used to pass data to the filter.
4d96a914 222 */
95bcf498 223 int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
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224
225 /**
226 * Filter uninitialization function. Should deallocate any memory held
227 * by the filter, release any picture references, etc. This does not need
228 * to deallocate the AVFilterContext->priv memory itself.
229 */
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230 void (*uninit)(AVFilterContext *ctx);
231
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232 const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none
233 const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
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234} AVFilter;
235
13ff8fd0 236/** An instance of a filter */
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237struct AVFilterContext
238{
13ff8fd0 239 AVClass *av_class; ///< Needed for av_log()
a5cbb2f4 240
13ff8fd0 241 AVFilter *filter; ///< The AVFilter of which this is an instance
a5cbb2f4 242
13ff8fd0 243 char *name; ///< name of this filter instance
dcea2482 244
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245 unsigned input_count; ///< number of input pads
246 AVFilterPad *input_pads; ///< array of input pads
247 AVFilterLink **inputs; ///< array of pointers to input links
25f8e601 248
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249 unsigned output_count; ///< number of output pads
250 AVFilterPad *output_pads; ///< array of output pads
251 AVFilterLink **outputs; ///< array of pointers to output links
a5cbb2f4 252
13ff8fd0 253 void *priv; ///< private data for use by the filter
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254};
255
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256/**
257 * A links between two filters. This contains pointers to the source and
258 * destination filters between which this link exists, and the indices of
259 * the pads involved. In addition, this link also contains the parameters
260 * which have been negotiated and agreed upon between the filter, such as
261 * image dimensions, format, etc
262 */
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263struct AVFilterLink
264{
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265 AVFilterContext *src; ///< source filter
266 unsigned int srcpad; ///< index of the output pad on the source filter
a5cbb2f4 267
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268 AVFilterContext *dst; ///< dest filter
269 unsigned int dstpad; ///< index of the input pad on the dest filter
a5cbb2f4 270
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271 int w; ///< agreed upon image width
272 int h; ///< agreed upon image height
273 enum PixelFormat format; ///< agreed upon image colorspace
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274
275 AVFilterPicRef *cur_pic;
462f57db 276 AVFilterPicRef *outpic;
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277};
278
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279/**
280 * Link two filters together
281 * @param src The source filter
282 * @param srcpad Index of the output pad on the source filter
283 * @param dst The destination filter
284 * @param dstpad Index of the input pad on the destination filter
285 * @return Zero on success
286 */
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287int avfilter_link(AVFilterContext *src, unsigned srcpad,
288 AVFilterContext *dst, unsigned dstpad);
289
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290/**
291 * Negotiate the colorspace, dimensions, etc of a link
292 * @param link The link to negotiate the properties of
293 * @return Zero on successful negotiation
294 */
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295int avfilter_config_link(AVFilterLink *link);
296
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297/**
298 * Request a picture buffer with a specific set of permissions
299 * @param link The output link to the filter from which the picture will
300 * be requested
301 * @param perms The required access permissions
302 * @return A reference to the picture. This must be unreferenced with
303 * avfilter_unref_pic when you are finished with it.
304 */
a5cbb2f4 305AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
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306
307/**
308 * Request an input frame from the filter at the other end of the link.
309 * @param link The input link
310 * @return Zero on success
311 */
63f64e6f 312int avfilter_request_frame(AVFilterLink *link);
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313
314/**
b42a6a92 315 * Notify the next filter of the start of a frame.
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316 * @param link The output link the frame will be sent over
317 * @param picref A reference to the frame about to be sent. The data for this
318 * frame need only be valid once draw_slice() is called for that
319 * portion. The receiving filter will free this reference when
320 * it no longer needs it.
321 */
a5cbb2f4 322void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
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323
324/**
325 * Notify the next filter that the current frame has finished
326 * @param link The output link the frame was sent over
327 */
a5cbb2f4 328void avfilter_end_frame(AVFilterLink *link);
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329
330/**
331 * Send a slice to the next filter
332 * @param link The output link over which the frame is being sent
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333 * @param y Offset in pixels from the top of the image for this slice
334 * @param h Height of this slice in pixels
335 */
72f6d631 336void avfilter_draw_slice(AVFilterLink *link, int y, int h);
a5cbb2f4 337
13ff8fd0 338/** Initialize the filter system. Registers all builtin filters */
a5cbb2f4 339void avfilter_init(void);
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340
341/** Uninitialize the filter system. Unregisters all filters */
a5cbb2f4 342void avfilter_uninit(void);
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343
344/**
345 * Register a filter. This is only needed if you plan to create an instance of
346 * this filter by name later with avfilter_create_by_name. A filter can still
347 * by created with acfilter_create even if it is not registered.
348 * @param filter The filter to register
349 */
a5cbb2f4 350void avfilter_register(AVFilter *filter);
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351
352/**
353 * Gets a filter definition matching the given name
354 * @param name The filter name to find
355 * @return The filter definition, if any matching one is registered.
356 * NULL if none found.
357 */
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358AVFilter *avfilter_get_by_name(char *name);
359
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360/**
361 * Create a filter instance
362 * @param filter The filter to create an instance of
363 * @param inst_name Name to give to the new instance. Can be NULL for none.
364 * @return Pointer to the new instance on success. NULL on failure.
365 */
dcea2482 366AVFilterContext *avfilter_create(AVFilter *filter, char *inst_name);
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367
368/**
369 * Creates a filter instace
370 * @param name The name of the filter type which is to be instantiated
371 * @param inst_name Name to give to the new instance. Can be NULL for none.
372 * @return Pointer to the new instance on success. NULL in failure.
373 */
dcea2482 374AVFilterContext *avfilter_create_by_name(char *name, char *inst_name);
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375
376/**
377 * Initialize a filter
378 * @param filter The filter to initialize
379 * @param args A string of parameters to use when initializing the filter.
380 * The format and meaning of this string varies by filter.
381 * @param opaque Any extra non-string data needed by the filter. The meaning
382 * of this parameter varies by filter.
383 * @return Zero on success
384 */
6e365c57 385int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
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386
387/**
388 * Destroy a filter
389 * @param filter The filter to destroy
390 */
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391void avfilter_destroy(AVFilterContext *filter);
392
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393/**
394 * Helper function to create a list of supported formats. This is intended
395 * for use in AVFilterPad->query_formats().
396 * @param len The number of formats supported
397 * @param ... A list of the supported formats
398 * @return The format list in a form suitable for returning from
399 * AVFilterPad->query_formats()
400 */
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401int *avfilter_make_format_list(int len, ...);
402
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403/**
404 * Insert a new pad
405 * @param idx Insertion point. Pad is inserted at the end if this point
406 * is beyond the end of the list of pads.
407 * @param count Pointer to the number of pads in the list
408 * @param padidx_off Offset within an AVFilterLink structure to the element
409 * to increment when inserting a new pad causes link
410 * numbering to change
411 * @param pads Pointer to the pointer to the beginning of the list of pads
412 * @param links Pointer to the pointer to the beginning of the list of links
413 * @param newpad The new pad to add. A copy is made when adding.
414 */
415void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
416 AVFilterPad **pads, AVFilterLink ***links,
417 AVFilterPad *newpad);
418
419/** insert a new input pad for the filter */
420static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
421 AVFilterPad *p)
422{
423 avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
424 &f->input_pads, &f->inputs, p);
425}
426
427/** insert a new output pad for the filter */
428static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
429 AVFilterPad *p)
430{
431 avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
432 &f->output_pads, &f->outputs, p);
433}
434
a5cbb2f4 435#endif /* FFMPEG_AVFILTER_H */