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 #define LIBAVFILTER_VERSION_MAJOR  0
  26 #define LIBAVFILTER_VERSION_MINOR  0
  27 #define LIBAVFILTER_VERSION_MICRO  0
  28
  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
  36
  37 #include <stddef.h>
  38 #include "avcodec.h"
  39
  40 typedef struct AVFilterContext AVFilterContext;
  41 typedef struct AVFilterLink    AVFilterLink;
  42 typedef struct AVFilterPad     AVFilterPad;
  43
  44 /* TODO: look for other flags which may be useful in this structure (interlace
  45  * flags, etc)
  46  */
  47 /**
  48  * A reference-counted picture data type used by the filter system.  Filters
  49  * should not store pointers to this structure directly, but instead use the
  50  * AVFilterPicRef structure below.
  51  */
  52 typedef struct AVFilterPic
  53 {
  54     uint8_t *data[4];           ///< picture data for each plane
  55     int linesize[4];            ///< number of bytes per line
  56     enum PixelFormat format;    ///< colorspace
  57
  58     unsigned refcount;          ///< number of references to this image
  59
  60     /** private data to be used by a custom free function */
  61     void *priv;
  62     /**
  63      * A pointer to the function to deallocate this image if the default
  64      * function is not sufficient.  This could, for example, add the memory
  65      * back into a memory pool to be reused later without the overhead of
  66      * reallocating it from scratch.
  67      */
  68     void (*free)(struct AVFilterPic *pic);
  69 } AVFilterPic;
  70
  71 /**
  72  * A reference to an AVFilterPic.  Since filters can manipulate the origin of
  73  * a picture to, for example, crop image without any memcpy, the picture origin
  74  * and dimensions are per-reference properties.  Linesize is also useful for
  75  * image flipping, frame to field filters, etc, and so is also per-reference.
  76  *
  77  * TODO: add anything necessary for frame reordering
  78  */
  79 typedef struct AVFilterPicRef
  80 {
  81     AVFilterPic *pic;           ///< the picture that this is a reference to
  82     uint8_t *data[4];           ///< picture data for each plane
  83     int linesize[4];            ///< number of bytes per line
  84     int w;                      ///< image width
  85     int h;                      ///< image height
  86
  87     int64_t pts;                ///< presentation timestamp in units of 1/AV_TIME_BASE
  88
  89     AVRational pixel_aspect;    ///< pixel aspect ratio
  90
  91     int perms;                  ///< permissions
  92 #define AV_PERM_READ     0x01   ///< can read from the buffer
  93 #define AV_PERM_WRITE    0x02   ///< can write to the buffer
  94 #define AV_PERM_PRESERVE 0x04   ///< nobody else can overwrite the buffer
  95 #define AV_PERM_REUSE    0x08   ///< can output the buffer multiple times, with the same contents each time
  96 #define AV_PERM_REUSE2   0x10   ///< can output the buffer multiple times, modified each time
  97 } AVFilterPicRef;
  98
  99 /**
 100  * Add a new reference to a picture.
 101  * @param ref   an existing reference to the picture
 102  * @param pmask a bitmask containing the allowable permissions in the new
 103  *              reference
 104  * @return      a new reference to the picture with the same properties as the
 105  *              old, excluding any permissions denied by pmask
 106  */
 107 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
 108
 109 /**
 110  * Remove a reference to a picture.  If this is the last reference to the
 111  * picture, the picture itself is also automatically freed.
 112  * @param ref reference to the picture
 113  */
 114 void avfilter_unref_pic(AVFilterPicRef *ref);
 115
 116 /**
 117  * A list of supported formats for one end of a filter link. This is used
 118  * during the format negotiation process to try to pick the best format to
 119  * use to minimize the number of necessary conversions. Each filter gives a
 120  * list of the formats supported by each input and output pad. The list
 121  * given for each pad need not be distinct - they may be references to the
 122  * same list of formats, as is often the case when a filter supports multiple
 123  * formats, but will always outut the same format as it is given in input.
 124  *
 125  * In this way, a list of possible input formats and a list of possible
 126  * output formats are associated with each link. When a set of formats is
 127  * negotiated over a link, the input and output lists are merged to form a
 128  * new list containing only the common elements of each list. In the case
 129  * that there were no common elements, a format conversion is necessary.
 130  * Otherwise, the lists are merged, and all other links which reference
 131  * either of the format lists involved in the merge are also affected.
 132  *
 133  * For example, consider the filter chain:
 134  * filter (a) --> (b) filter (b) --> (c) filter
 135  *
 136  * where the letters in parenthesis indicate a list of formats supported on
 137  * the input or output of the link. Suppose the lists are as follows:
 138  * (a) = {A, B}
 139  * (b) = {A, B, C}
 140  * (c) = {B, C}
 141  *
 142  * First, the first link's lists are merged, yielding:
 143  * filter (a) --> (a) filter (a) --> (c) filter
 144  *
 145  * Notice that format list (b) now refers to the same list as filter list (a).
 146  * Next, the lists for the second link are merged, yielding:
 147  * filter (a) --> (a) filter (a) --> (a) filter
 148  *
 149  * where (a) = {B}.
 150  *
 151  * Unfortunately, when the format lists at the two ends of a link are merged,
 152  * we must ensure that all links which reference either pre-merge format list
 153  * get updated as well. Therefore, we have the format list structure store a
 154  * pointer to each of the pointers to itself.
 155  */
 156 typedef struct AVFilterFormats AVFilterFormats;
 157 struct AVFilterFormats
 158 {
 159     unsigned format_count;      ///< number of formats
 160     int *formats;               ///< list of formats
 161
 162     unsigned refcount;          ///< number of references to this list
 163     AVFilterFormats ***refs;    ///< references to this list
 164 };
 165
 166 /**
 167  * Helper function to create a list of supported formats.  This is intended
 168  * for use in AVFilter->query_formats().
 169  * @param len the number of formats supported
 170  * @param ... a list of the supported formats
 171  * @return    the format list, with no existing references
 172  */
 173 AVFilterFormats *avfilter_make_format_list(int len, ...);
 174
 175 /**
 176  * Returns a list of all colorspaces supported by FFmpeg.
 177  */
 178 AVFilterFormats *avfilter_all_colorspaces(void);
 179
 180 /**
 181  * Returns a format list which contains the intersection of the formats of
 182  * a and b. And all the references of a and b, and a and b will be
 183  * deallocated.
 184  *
 185  * If a and b do not share any common formats, neither is modified, and NULL
 186  * is returned.
 187  */
 188 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
 189
 190 /**
 191  * Adds *ref as a new reference to formats.
 192  * That is the pointers will point like in the ascii art below:
 193  *   ________
 194  *  |formats |<--------.
 195  *  |  ____  |     ____|___________________
 196  *  | |refs| |    |  __|_
 197  *  | |* * | |    | |  | |  AVFilterLink
 198  *  | |* *--------->|*ref|
 199  *  | |____| |    | |____|
 200  *  |________|    |________________________
 201  */
 202 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
 203
 204 /**
 205  * Remove *ref as a reference to the format list it currently points to,
 206  * deallocate that list if this was the last reference, and set *ref to NULL.
 207  *
 208  *         Before                                 After
 209  *   ________                               ________         NULL
 210  *  |formats |<--------.                   |formats |         ^
 211  *  |  ____  |     ____|________________   |  ____  |     ____|________________
 212  *  | |refs| |    |  __|_                  | |refs| |    |  __|_
 213  *  | |* * | |    | |  | |  AVFilterLink   | |* * | |    | |  | |  AVFilterLink
 214  *  | |* *--------->|*ref|                 | |*   | |    | |*ref|
 215  *  | |____| |    | |____|                 | |____| |    | |____|
 216  *  |________|    |_____________________   |________|    |_____________________
 217  */
 218 void avfilter_formats_unref(AVFilterFormats **ref);
 219
 220 /**
 221  *
 222  *         Before                                 After
 223  *   ________                         ________
 224  *  |formats |<---------.            |formats |<---------.
 225  *  |  ____  |       ___|___         |  ____  |       ___|___
 226  *  | |refs| |      |   |   |        | |refs| |      |   |   |   NULL
 227  *  | |* *--------->|*oldref|        | |* *--------->|*newref|     ^
 228  *  | |* * | |      |_______|        | |* * | |      |_______|  ___|___
 229  *  | |____| |                       | |____| |                |   |   |
 230  *  |________|                       |________|                |*oldref|
 231  *                                                             |_______|
 232  */
 233 void avfilter_formats_changeref(AVFilterFormats **oldref,
 234                                 AVFilterFormats **newref);
 235
 236 /**
 237  * A filter pad used for either input or output.
 238  */
 239 struct AVFilterPad
 240 {
 241     /**
 242      * Pad name.  The name is unique among inputs and among outputs, but an
 243      * input may have the same name as an output.  This may be NULL if this
 244      * pad has no need to ever be referenced by name.
 245      */
 246     const char *name;
 247
 248     /**
 249      * AVFilterPad type.  Only video supported now, hopefully someone will
 250      * add audio in the future.
 251      */
 252     enum CodecType type;
 253
 254     /**
 255      * Minimum required permissions on incoming buffers.  Any buffers with
 256      * insufficient permissions will be automatically copied by the filter
 257      * system to a new buffer which provides the needed access permissions.
 258      *
 259      * Input pads only.
 260      */
 261     int min_perms;
 262
 263     /**
 264      * Permissions which are not accepted on incoming buffers.  Any buffer
 265      * which has any of these permissions set be automatically copied by the
 266      * filter system to a new buffer which does not have those permissions.
 267      * This can be used to easily disallow buffers with AV_PERM_REUSE.
 268      *
 269      * Input pads only.
 270      */
 271     int rej_perms;
 272
 273     /**
 274      * Callback called before passing the first slice of a new frame.  If
 275      * NULL, the filter layer will default to storing a reference to the
 276      * picture inside the link structure.
 277      *
 278      * Input video pads only.
 279      */
 280     void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
 281
 282     /**
 283      * Callback function to get a buffer.  If NULL, the filter system will
 284      * handle buffer requests.
 285      *
 286      * Input video pads only.
 287      */
 288     AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
 289
 290     /**
 291      * Callback called after the slices of a frame are completely sent.  If
 292      * NULL, the filter layer will default to releasing the reference stored
 293      * in the link structure during start_frame().
 294      *
 295      * Input video pads only.
 296      */
 297     void (*end_frame)(AVFilterLink *link);
 298
 299     /**
 300      * Slice drawing callback.  This is where a filter receives video data
 301      * and should do its processing.
 302      *
 303      * Input video pads only.
 304      */
 305     void (*draw_slice)(AVFilterLink *link, int y, int height);
 306
 307     /**
 308      * Frame poll callback.  This returns the number of immediately available
 309      * frames. It should return a positive value if the next request_frame()
 310      * is guaranteed to return one frame (with no delay).
 311      *
 312      * Defaults to just calling the source poll_frame() method.
 313      *
 314      * Output video pads only.
 315      */
 316     int (*poll_frame)(AVFilterLink *link);
 317
 318     /**
 319      * Frame request callback.  A call to this should result in at least one
 320      * frame being output over the given link.  This should return zero on
 321      * success, and another value on error.
 322      *
 323      * Output video pads only.
 324      */
 325     int (*request_frame)(AVFilterLink *link);
 326
 327     /**
 328      * Link configuration callback.
 329      *
 330      * For output pads, this should set the link properties such as
 331      * width/height.  This should NOT set the format property - that is
 332      * negotiated between filters by the filter system using the
 333      * query_formats() callback before this function is called.
 334      *
 335      * For input pads, this should check the properties of the link, and update
 336      * the filter's internal state as necessary.
 337      *
 338      * For both input and output filters, this should return zero on success,
 339      * and another value on error.
 340      */
 341     int (*config_props)(AVFilterLink *link);
 342 };
 343
 344 /** Default handler for start_frame() for video inputs */
 345 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
 346 /** Default handler for end_frame() for video inputs */
 347 void avfilter_default_end_frame(AVFilterLink *link);
 348 /** Default handler for config_props() for video outputs */
 349 int avfilter_default_config_output_link(AVFilterLink *link);
 350 /** Default handler for config_props() for video inputs */
 351 int avfilter_default_config_input_link (AVFilterLink *link);
 352 /** Default handler for get_video_buffer() for video inputs */
 353 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
 354                                                   int perms);
 355 /**
 356  * A helper for query_formats() which sets all links to the same list of
 357  * formats. If there are no links hooked to this filter, the list of formats is
 358  * freed.
 359  */
 360 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
 361 /** Default handler for query_formats() */
 362 int avfilter_default_query_formats(AVFilterContext *ctx);
 363
 364 /**
 365  * Filter definition.  This defines the pads a filter contains, and all the
 366  * callback functions used to interact with the filter.
 367  */
 368 typedef struct
 369 {
 370     const char *name;         ///< filter name
 371
 372     int priv_size;      ///< size of private data to allocate for the filter
 373
 374     /**
 375      * Filter initialization function.  Args contains the user-supplied
 376      * parameters.  FIXME: maybe an AVOption-based system would be better?
 377      * opaque is data provided by the code requesting creation of the filter,
 378      * and is used to pass data to the filter.
 379      */
 380     int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
 381
 382     /**
 383      * Filter uninitialization function.  Should deallocate any memory held
 384      * by the filter, release any picture references, etc.  This does not need
 385      * to deallocate the AVFilterContext->priv memory itself.
 386      */
 387     void (*uninit)(AVFilterContext *ctx);
 388
 389     /**
 390      * Query formats supported by the filter and its pads. Should set the
 391      * in_formats for links connected to its output pads, and out_formats
 392      * for links connected to its input pads.
 393      *
 394      * Should return zero on success.
 395      */
 396     int (*query_formats)(AVFilterContext *);
 397
 398     const AVFilterPad *inputs;  ///< NULL terminated list of inputs. NULL if none
 399     const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
 400 } AVFilter;
 401
 402 /** An instance of a filter */
 403 struct AVFilterContext
 404 {
 405     const AVClass *av_class;              ///< needed for av_log()
 406
 407     AVFilter *filter;               ///< the AVFilter of which this is an instance
 408
 409     char *name;                     ///< name of this filter instance
 410
 411     unsigned input_count;           ///< number of input pads
 412     AVFilterPad   *input_pads;      ///< array of input pads
 413     AVFilterLink **inputs;          ///< array of pointers to input links
 414
 415     unsigned output_count;          ///< number of output pads
 416     AVFilterPad   *output_pads;     ///< array of output pads
 417     AVFilterLink **outputs;         ///< array of pointers to output links
 418
 419     void *priv;                     ///< private data for use by the filter
 420 };
 421
 422 /**
 423  * A link between two filters.  This contains pointers to the source and
 424  * destination filters between which this link exists, and the indices of
 425  * the pads involved.  In addition, this link also contains the parameters
 426  * which have been negotiated and agreed upon between the filter, such as
 427  * image dimensions, format, etc
 428  */
 429 struct AVFilterLink
 430 {
 431     AVFilterContext *src;       ///< source filter
 432     unsigned int srcpad;        ///< index of the output pad on the source filter
 433
 434     AVFilterContext *dst;       ///< dest filter
 435     unsigned int dstpad;        ///< index of the input pad on the dest filter
 436
 437     /** stage of the initialization of the link properties (dimensions, etc) */
 438     enum {
 439         AVLINK_UNINIT = 0,      ///< not started
 440         AVLINK_STARTINIT,       ///< started, but incomplete
 441         AVLINK_INIT             ///< complete
 442     } init_state;
 443
 444     int w;                      ///< agreed upon image width
 445     int h;                      ///< agreed upon image height
 446     enum PixelFormat format;    ///< agreed upon image colorspace
 447
 448     /**
 449      * Lists of formats supported by the input and output filters respectively.
 450      * These lists are used for negotiating the format to actually be used,
 451      * which will be loaded into the format member, above, when chosen.
 452      */
 453     AVFilterFormats *in_formats;
 454     AVFilterFormats *out_formats;
 455
 456     /**
 457      * The picture reference currently being sent across the link by the source
 458      * filter.  This is used internally by the filter system to allow
 459      * automatic copying of pictures which do not have sufficient permissions
 460      * for the destination.  This should not be accessed directly by the
 461      * filters.
 462      */
 463     AVFilterPicRef *srcpic;
 464
 465     AVFilterPicRef *cur_pic;
 466     AVFilterPicRef *outpic;
 467 };
 468
 469 /**
 470  * Link two filters together.
 471  * @param src    the source filter
 472  * @param srcpad index of the output pad on the source filter
 473  * @param dst    the destination filter
 474  * @param dstpad index of the input pad on the destination filter
 475  * @return       zero on success
 476  */
 477 int avfilter_link(AVFilterContext *src, unsigned srcpad,
 478                   AVFilterContext *dst, unsigned dstpad);
 479
 480 /**
 481  * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
 482  * @param filter the filter to negotiate the properties for its inputs
 483  * @return       zero on successful negotiation
 484  */
 485 int avfilter_config_links(AVFilterContext *filter);
 486
 487 /**
 488  * Request a picture buffer with a specific set of permissions
 489  * @param link  the output link to the filter from which the picture will
 490  *              be requested
 491  * @param perms the required access permissions
 492  * @return      A reference to the picture.  This must be unreferenced with
 493  *              avfilter_unref_pic when you are finished with it.
 494  */
 495 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
 496
 497 /**
 498  * Request an input frame from the filter at the other end of the link.
 499  * @param link the input link
 500  * @return     zero on success
 501  */
 502 int avfilter_request_frame(AVFilterLink *link);
 503
 504 /**
 505  * Poll a frame from the filter chain.
 506  * @param  link the input link
 507  * @return      the number of imediately available frames
 508  */
 509 int avfilter_poll_frame(AVFilterLink *link);
 510
 511 /**
 512  * Notify the next filter of the start of a frame.
 513  * @param link   the output link the frame will be sent over
 514  * @param picref A reference to the frame about to be sent.  The data for this
 515  *               frame need only be valid once draw_slice() is called for that
 516  *               portion.  The receiving filter will free this reference when
 517  *               it no longer needs it.
 518  */
 519 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
 520
 521 /**
 522  * Notify the next filter that the current frame has finished
 523  * @param link the output link the frame was sent over
 524  */
 525 void avfilter_end_frame(AVFilterLink *link);
 526
 527 /**
 528  * Send a slice to the next filter.
 529  * @param link the output link over which the frame is being sent
 530  * @param y    offset in pixels from the top of the image for this slice
 531  * @param h    height of this slice in pixels
 532  */
 533 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
 534
 535 /** Initialize the filter system.  Registers all builtin filters */
 536 void avfilter_register_all(void);
 537
 538 /** Uninitialize the filter system.  Unregisters all filters */
 539 void avfilter_uninit(void);
 540
 541 /**
 542  * Register a filter.  This is only needed if you plan to use
 543  * avfilter_get_by_name later to lookup the AVFilter structure by name. A
 544  * filter can still by instantiated with avfilter_open even if it is not
 545  * registered.
 546  * @param filter the filter to register
 547  */
 548 void avfilter_register(AVFilter *filter);
 549
 550 /**
 551  * Gets a filter definition matching the given name.
 552  * @param name the filter name to find
 553  * @return     the filter definition, if any matching one is registered.
 554  *             NULL if none found.
 555  */
 556 AVFilter *avfilter_get_by_name(const char *name);
 557
 558 /**
 559  * Create a filter instance.
 560  * @param filter    the filter to create an instance of
 561  * @param inst_name Name to give to the new instance.  Can be NULL for none.
 562  * @return          Pointer to the new instance on success.  NULL on failure.
 563  */
 564 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
 565
 566 /**
 567  * Initialize a filter.
 568  * @param filter the filter to initialize
 569  * @param args   A string of parameters to use when initializing the filter.
 570  *               The format and meaning of this string varies by filter.
 571  * @param opaque Any extra non-string data needed by the filter.  The meaning
 572  *               of this parameter varies by filter.
 573  * @return       zero on success
 574  */
 575 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
 576
 577 /**
 578  * Destroy a filter.
 579  * @param filter the filter to destroy
 580  */
 581 void avfilter_destroy(AVFilterContext *filter);
 582
 583 /**
 584  * Insert a filter in the middle of an existing link.
 585  * @param link the link into which the filter should be inserted
 586  * @param filt the filter to be inserted
 587  * @param in   the input pad on the filter to connect
 588  * @param out  the output pad on the filter to connect
 589  * @return     zero on success
 590  */
 591 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
 592                            unsigned in, unsigned out);
 593
 594 /**
 595  * Insert a new pad.
 596  * @param idx Insertion point.  Pad is inserted at the end if this point
 597  *            is beyond the end of the list of pads.
 598  * @param count Pointer to the number of pads in the list
 599  * @param padidx_off Offset within an AVFilterLink structure to the element
 600  *                   to increment when inserting a new pad causes link
 601  *                   numbering to change
 602  * @param pads Pointer to the pointer to the beginning of the list of pads
 603  * @param links Pointer to the pointer to the beginning of the list of links
 604  * @param newpad The new pad to add. A copy is made when adding.
 605  */
 606 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
 607                          AVFilterPad **pads, AVFilterLink ***links,
 608                          AVFilterPad *newpad);
 609
 610 /** insert a new input pad for the filter */
 611 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
 612                                          AVFilterPad *p)
 613 {
 614     avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
 615                         &f->input_pads, &f->inputs, p);
 616 }
 617
 618 /** insert a new output pad for the filter */
 619 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
 620                                           AVFilterPad *p)
 621 {
 622     avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
 623                         &f->output_pads, &f->outputs, p);
 624 }
 625
 626 #endif  /* FFMPEG_AVFILTER_H */