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 AVFILTER_AVFILTER_H
  23 #define AVFILTER_AVFILTER_H
  24
  25 #define LIBAVFILTER_VERSION_MAJOR  0
  26 #define LIBAVFILTER_VERSION_MINOR  1
  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 "libavcodec/avcodec.h"
  39
  40 /**
  41  * Returns the LIBAVFILTER_VERSION_INT constant.
  42  */
  43 unsigned avfilter_version(void);
  44
  45 typedef struct AVFilterContext AVFilterContext;
  46 typedef struct AVFilterLink    AVFilterLink;
  47 typedef struct AVFilterPad     AVFilterPad;
  48
  49 /* TODO: look for other flags which may be useful in this structure (interlace
  50  * flags, etc)
  51  */
  52 /**
  53  * A reference-counted picture data type used by the filter system.  Filters
  54  * should not store pointers to this structure directly, but instead use the
  55  * AVFilterPicRef structure below.
  56  */
  57 typedef struct AVFilterPic
  58 {
  59     uint8_t *data[4];           ///< picture data for each plane
  60     int linesize[4];            ///< number of bytes per line
  61     enum PixelFormat format;    ///< colorspace
  62
  63     unsigned refcount;          ///< number of references to this image
  64
  65     /** private data to be used by a custom free function */
  66     void *priv;
  67     /**
  68      * A pointer to the function to deallocate this image if the default
  69      * function is not sufficient.  This could, for example, add the memory
  70      * back into a memory pool to be reused later without the overhead of
  71      * reallocating it from scratch.
  72      */
  73     void (*free)(struct AVFilterPic *pic);
  74 } AVFilterPic;
  75
  76 /**
  77  * A reference to an AVFilterPic.  Since filters can manipulate the origin of
  78  * a picture to, for example, crop image without any memcpy, the picture origin
  79  * and dimensions are per-reference properties.  Linesize is also useful for
  80  * image flipping, frame to field filters, etc, and so is also per-reference.
  81  *
  82  * TODO: add anything necessary for frame reordering
  83  */
  84 typedef struct AVFilterPicRef
  85 {
  86     AVFilterPic *pic;           ///< the picture that this is a reference to
  87     uint8_t *data[4];           ///< picture data for each plane
  88     int linesize[4];            ///< number of bytes per line
  89     int w;                      ///< image width
  90     int h;                      ///< image height
  91
  92     int64_t pts;                ///< presentation timestamp in units of 1/AV_TIME_BASE
  93
  94     AVRational pixel_aspect;    ///< pixel aspect ratio
  95
  96     int perms;                  ///< permissions
  97 #define AV_PERM_READ     0x01   ///< can read from the buffer
  98 #define AV_PERM_WRITE    0x02   ///< can write to the buffer
  99 #define AV_PERM_PRESERVE 0x04   ///< nobody else can overwrite the buffer
 100 #define AV_PERM_REUSE    0x08   ///< can output the buffer multiple times, with the same contents each time
 101 #define AV_PERM_REUSE2   0x10   ///< can output the buffer multiple times, modified each time
 102 } AVFilterPicRef;
 103
 104 /**
 105  * Add a new reference to a picture.
 106  * @param ref   an existing reference to the picture
 107  * @param pmask a bitmask containing the allowable permissions in the new
 108  *              reference
 109  * @return      a new reference to the picture with the same properties as the
 110  *              old, excluding any permissions denied by pmask
 111  */
 112 AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask);
 113
 114 /**
 115  * Remove a reference to a picture.  If this is the last reference to the
 116  * picture, the picture itself is also automatically freed.
 117  * @param ref reference to the picture
 118  */
 119 void avfilter_unref_pic(AVFilterPicRef *ref);
 120
 121 /**
 122  * A list of supported formats for one end of a filter link. This is used
 123  * during the format negotiation process to try to pick the best format to
 124  * use to minimize the number of necessary conversions. Each filter gives a
 125  * list of the formats supported by each input and output pad. The list
 126  * given for each pad need not be distinct - they may be references to the
 127  * same list of formats, as is often the case when a filter supports multiple
 128  * formats, but will always output the same format as it is given in input.
 129  *
 130  * In this way, a list of possible input formats and a list of possible
 131  * output formats are associated with each link. When a set of formats is
 132  * negotiated over a link, the input and output lists are merged to form a
 133  * new list containing only the common elements of each list. In the case
 134  * that there were no common elements, a format conversion is necessary.
 135  * Otherwise, the lists are merged, and all other links which reference
 136  * either of the format lists involved in the merge are also affected.
 137  *
 138  * For example, consider the filter chain:
 139  * filter (a) --> (b) filter (b) --> (c) filter
 140  *
 141  * where the letters in parenthesis indicate a list of formats supported on
 142  * the input or output of the link. Suppose the lists are as follows:
 143  * (a) = {A, B}
 144  * (b) = {A, B, C}
 145  * (c) = {B, C}
 146  *
 147  * First, the first link's lists are merged, yielding:
 148  * filter (a) --> (a) filter (a) --> (c) filter
 149  *
 150  * Notice that format list (b) now refers to the same list as filter list (a).
 151  * Next, the lists for the second link are merged, yielding:
 152  * filter (a) --> (a) filter (a) --> (a) filter
 153  *
 154  * where (a) = {B}.
 155  *
 156  * Unfortunately, when the format lists at the two ends of a link are merged,
 157  * we must ensure that all links which reference either pre-merge format list
 158  * get updated as well. Therefore, we have the format list structure store a
 159  * pointer to each of the pointers to itself.
 160  */
 161 typedef struct AVFilterFormats AVFilterFormats;
 162 struct AVFilterFormats
 163 {
 164     unsigned format_count;      ///< number of formats
 165     int *formats;               ///< list of formats
 166
 167     unsigned refcount;          ///< number of references to this list
 168     AVFilterFormats ***refs;    ///< references to this list
 169 };
 170
 171 /**
 172  * Helper function to create a list of supported formats.  This is intended
 173  * for use in AVFilter->query_formats().
 174  * @param len the number of formats supported
 175  * @param ... a list of the supported formats
 176  * @return    the format list, with no existing references
 177  */
 178 AVFilterFormats *avfilter_make_format_list(int len, ...);
 179
 180 /**
 181  * Returns a list of all colorspaces supported by FFmpeg.
 182  */
 183 AVFilterFormats *avfilter_all_colorspaces(void);
 184
 185 /**
 186  * Returns a format list which contains the intersection of the formats of
 187  * a and b. Also, all the references of a, all the references of b, and
 188  * a and b themselves will be deallocated.
 189  *
 190  * If a and b do not share any common formats, neither is modified, and NULL
 191  * is returned.
 192  */
 193 AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b);
 194
 195 /**
 196  * Adds *ref as a new reference to formats.
 197  * That is the pointers will point like in the ascii art below:
 198  *   ________
 199  *  |formats |<--------.
 200  *  |  ____  |     ____|___________________
 201  *  | |refs| |    |  __|_
 202  *  | |* * | |    | |  | |  AVFilterLink
 203  *  | |* *--------->|*ref|
 204  *  | |____| |    | |____|
 205  *  |________|    |________________________
 206  */
 207 void avfilter_formats_ref(AVFilterFormats *formats, AVFilterFormats **ref);
 208
 209 /**
 210  * Remove *ref as a reference to the format list it currently points to,
 211  * deallocate that list if this was the last reference, and set *ref to NULL.
 212  *
 213  *         Before                                 After
 214  *   ________                               ________         NULL
 215  *  |formats |<--------.                   |formats |         ^
 216  *  |  ____  |     ____|________________   |  ____  |     ____|________________
 217  *  | |refs| |    |  __|_                  | |refs| |    |  __|_
 218  *  | |* * | |    | |  | |  AVFilterLink   | |* * | |    | |  | |  AVFilterLink
 219  *  | |* *--------->|*ref|                 | |*   | |    | |*ref|
 220  *  | |____| |    | |____|                 | |____| |    | |____|
 221  *  |________|    |_____________________   |________|    |_____________________
 222  */
 223 void avfilter_formats_unref(AVFilterFormats **ref);
 224
 225 /**
 226  *
 227  *         Before                                 After
 228  *   ________                         ________
 229  *  |formats |<---------.            |formats |<---------.
 230  *  |  ____  |       ___|___         |  ____  |       ___|___
 231  *  | |refs| |      |   |   |        | |refs| |      |   |   |   NULL
 232  *  | |* *--------->|*oldref|        | |* *--------->|*newref|     ^
 233  *  | |* * | |      |_______|        | |* * | |      |_______|  ___|___
 234  *  | |____| |                       | |____| |                |   |   |
 235  *  |________|                       |________|                |*oldref|
 236  *                                                             |_______|
 237  */
 238 void avfilter_formats_changeref(AVFilterFormats **oldref,
 239                                 AVFilterFormats **newref);
 240
 241 /**
 242  * A filter pad used for either input or output.
 243  */
 244 struct AVFilterPad
 245 {
 246     /**
 247      * Pad name.  The name is unique among inputs and among outputs, but an
 248      * input may have the same name as an output.  This may be NULL if this
 249      * pad has no need to ever be referenced by name.
 250      */
 251     const char *name;
 252
 253     /**
 254      * AVFilterPad type.  Only video supported now, hopefully someone will
 255      * add audio in the future.
 256      */
 257     enum CodecType type;
 258
 259     /**
 260      * Minimum required permissions on incoming buffers.  Any buffers with
 261      * insufficient permissions will be automatically copied by the filter
 262      * system to a new buffer which provides the needed access permissions.
 263      *
 264      * Input pads only.
 265      */
 266     int min_perms;
 267
 268     /**
 269      * Permissions which are not accepted on incoming buffers.  Any buffer
 270      * which has any of these permissions set be automatically copied by the
 271      * filter system to a new buffer which does not have those permissions.
 272      * This can be used to easily disallow buffers with AV_PERM_REUSE.
 273      *
 274      * Input pads only.
 275      */
 276     int rej_perms;
 277
 278     /**
 279      * Callback called before passing the first slice of a new frame.  If
 280      * NULL, the filter layer will default to storing a reference to the
 281      * picture inside the link structure.
 282      *
 283      * Input video pads only.
 284      */
 285     void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref);
 286
 287     /**
 288      * Callback function to get a buffer.  If NULL, the filter system will
 289      * handle buffer requests.
 290      *
 291      * Input video pads only.
 292      */
 293     AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms);
 294
 295     /**
 296      * Callback called after the slices of a frame are completely sent.  If
 297      * NULL, the filter layer will default to releasing the reference stored
 298      * in the link structure during start_frame().
 299      *
 300      * Input video pads only.
 301      */
 302     void (*end_frame)(AVFilterLink *link);
 303
 304     /**
 305      * Slice drawing callback.  This is where a filter receives video data
 306      * and should do its processing.
 307      *
 308      * Input video pads only.
 309      */
 310     void (*draw_slice)(AVFilterLink *link, int y, int height);
 311
 312     /**
 313      * Frame poll callback.  This returns the number of immediately available
 314      * frames. It should return a positive value if the next request_frame()
 315      * is guaranteed to return one frame (with no delay).
 316      *
 317      * Defaults to just calling the source poll_frame() method.
 318      *
 319      * Output video pads only.
 320      */
 321     int (*poll_frame)(AVFilterLink *link);
 322
 323     /**
 324      * Frame request callback.  A call to this should result in at least one
 325      * frame being output over the given link.  This should return zero on
 326      * success, and another value on error.
 327      *
 328      * Output video pads only.
 329      */
 330     int (*request_frame)(AVFilterLink *link);
 331
 332     /**
 333      * Link configuration callback.
 334      *
 335      * For output pads, this should set the link properties such as
 336      * width/height.  This should NOT set the format property - that is
 337      * negotiated between filters by the filter system using the
 338      * query_formats() callback before this function is called.
 339      *
 340      * For input pads, this should check the properties of the link, and update
 341      * the filter's internal state as necessary.
 342      *
 343      * For both input and output filters, this should return zero on success,
 344      * and another value on error.
 345      */
 346     int (*config_props)(AVFilterLink *link);
 347 };
 348
 349 /** Default handler for start_frame() for video inputs */
 350 void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
 351 /** Default handler for end_frame() for video inputs */
 352 void avfilter_default_end_frame(AVFilterLink *link);
 353 /** Default handler for config_props() for video outputs */
 354 int avfilter_default_config_output_link(AVFilterLink *link);
 355 /** Default handler for config_props() for video inputs */
 356 int avfilter_default_config_input_link (AVFilterLink *link);
 357 /** Default handler for get_video_buffer() for video inputs */
 358 AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link,
 359                                                   int perms);
 360 /**
 361  * A helper for query_formats() which sets all links to the same list of
 362  * formats. If there are no links hooked to this filter, the list of formats is
 363  * freed.
 364  */
 365 void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats);
 366 /** Default handler for query_formats() */
 367 int avfilter_default_query_formats(AVFilterContext *ctx);
 368
 369 /**
 370  * Filter definition.  This defines the pads a filter contains, and all the
 371  * callback functions used to interact with the filter.
 372  */
 373 typedef struct
 374 {
 375     const char *name;         ///< filter name
 376
 377     int priv_size;      ///< size of private data to allocate for the filter
 378
 379     /**
 380      * Filter initialization function.  Args contains the user-supplied
 381      * parameters.  FIXME: maybe an AVOption-based system would be better?
 382      * opaque is data provided by the code requesting creation of the filter,
 383      * and is used to pass data to the filter.
 384      */
 385     int (*init)(AVFilterContext *ctx, const char *args, void *opaque);
 386
 387     /**
 388      * Filter uninitialization function.  Should deallocate any memory held
 389      * by the filter, release any picture references, etc.  This does not need
 390      * to deallocate the AVFilterContext->priv memory itself.
 391      */
 392     void (*uninit)(AVFilterContext *ctx);
 393
 394     /**
 395      * Query formats supported by the filter and its pads. Should set the
 396      * in_formats for links connected to its output pads, and out_formats
 397      * for links connected to its input pads.
 398      *
 399      * Should return zero on success.
 400      */
 401     int (*query_formats)(AVFilterContext *);
 402
 403     const AVFilterPad *inputs;  ///< NULL terminated list of inputs. NULL if none
 404     const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none
 405 } AVFilter;
 406
 407 /** An instance of a filter */
 408 struct AVFilterContext
 409 {
 410     const AVClass *av_class;              ///< needed for av_log()
 411
 412     AVFilter *filter;               ///< the AVFilter of which this is an instance
 413
 414     char *name;                     ///< name of this filter instance
 415
 416     unsigned input_count;           ///< number of input pads
 417     AVFilterPad   *input_pads;      ///< array of input pads
 418     AVFilterLink **inputs;          ///< array of pointers to input links
 419
 420     unsigned output_count;          ///< number of output pads
 421     AVFilterPad   *output_pads;     ///< array of output pads
 422     AVFilterLink **outputs;         ///< array of pointers to output links
 423
 424     void *priv;                     ///< private data for use by the filter
 425 };
 426
 427 /**
 428  * A link between two filters.  This contains pointers to the source and
 429  * destination filters between which this link exists, and the indexes of
 430  * the pads involved.  In addition, this link also contains the parameters
 431  * which have been negotiated and agreed upon between the filter, such as
 432  * image dimensions, format, etc
 433  */
 434 struct AVFilterLink
 435 {
 436     AVFilterContext *src;       ///< source filter
 437     unsigned int srcpad;        ///< index of the output pad on the source filter
 438
 439     AVFilterContext *dst;       ///< dest filter
 440     unsigned int dstpad;        ///< index of the input pad on the dest filter
 441
 442     /** stage of the initialization of the link properties (dimensions, etc) */
 443     enum {
 444         AVLINK_UNINIT = 0,      ///< not started
 445         AVLINK_STARTINIT,       ///< started, but incomplete
 446         AVLINK_INIT             ///< complete
 447     } init_state;
 448
 449     int w;                      ///< agreed upon image width
 450     int h;                      ///< agreed upon image height
 451     enum PixelFormat format;    ///< agreed upon image colorspace
 452
 453     /**
 454      * Lists of formats supported by the input and output filters respectively.
 455      * These lists are used for negotiating the format to actually be used,
 456      * which will be loaded into the format member, above, when chosen.
 457      */
 458     AVFilterFormats *in_formats;
 459     AVFilterFormats *out_formats;
 460
 461     /**
 462      * The picture reference currently being sent across the link by the source
 463      * filter.  This is used internally by the filter system to allow
 464      * automatic copying of pictures which do not have sufficient permissions
 465      * for the destination.  This should not be accessed directly by the
 466      * filters.
 467      */
 468     AVFilterPicRef *srcpic;
 469
 470     AVFilterPicRef *cur_pic;
 471     AVFilterPicRef *outpic;
 472 };
 473
 474 /**
 475  * Link two filters together.
 476  * @param src    the source filter
 477  * @param srcpad index of the output pad on the source filter
 478  * @param dst    the destination filter
 479  * @param dstpad index of the input pad on the destination filter
 480  * @return       zero on success
 481  */
 482 int avfilter_link(AVFilterContext *src, unsigned srcpad,
 483                   AVFilterContext *dst, unsigned dstpad);
 484
 485 /**
 486  * Negotiate the colorspace, dimensions, etc of all inputs to a filter.
 487  * @param filter the filter to negotiate the properties for its inputs
 488  * @return       zero on successful negotiation
 489  */
 490 int avfilter_config_links(AVFilterContext *filter);
 491
 492 /**
 493  * Request a picture buffer with a specific set of permissions
 494  * @param link  the output link to the filter from which the picture will
 495  *              be requested
 496  * @param perms the required access permissions
 497  * @return      A reference to the picture.  This must be unreferenced with
 498  *              avfilter_unref_pic when you are finished with it.
 499  */
 500 AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms);
 501
 502 /**
 503  * Request an input frame from the filter at the other end of the link.
 504  * @param link the input link
 505  * @return     zero on success
 506  */
 507 int avfilter_request_frame(AVFilterLink *link);
 508
 509 /**
 510  * Poll a frame from the filter chain.
 511  * @param  link the input link
 512  * @return      the number of imediately available frames
 513  */
 514 int avfilter_poll_frame(AVFilterLink *link);
 515
 516 /**
 517  * Notify the next filter of the start of a frame.
 518  * @param link   the output link the frame will be sent over
 519  * @param picref A reference to the frame about to be sent.  The data for this
 520  *               frame need only be valid once draw_slice() is called for that
 521  *               portion.  The receiving filter will free this reference when
 522  *               it no longer needs it.
 523  */
 524 void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref);
 525
 526 /**
 527  * Notify the next filter that the current frame has finished
 528  * @param link the output link the frame was sent over
 529  */
 530 void avfilter_end_frame(AVFilterLink *link);
 531
 532 /**
 533  * Send a slice to the next filter.
 534  * @param link the output link over which the frame is being sent
 535  * @param y    offset in pixels from the top of the image for this slice
 536  * @param h    height of this slice in pixels
 537  */
 538 void avfilter_draw_slice(AVFilterLink *link, int y, int h);
 539
 540 /** Initialize the filter system.  Registers all builtin filters */
 541 void avfilter_register_all(void);
 542
 543 /** Uninitialize the filter system.  Unregisters all filters */
 544 void avfilter_uninit(void);
 545
 546 /**
 547  * Register a filter.  This is only needed if you plan to use
 548  * avfilter_get_by_name later to lookup the AVFilter structure by name. A
 549  * filter can still by instantiated with avfilter_open even if it is not
 550  * registered.
 551  * @param filter the filter to register
 552  */
 553 void avfilter_register(AVFilter *filter);
 554
 555 /**
 556  * Gets a filter definition matching the given name.
 557  * @param name the filter name to find
 558  * @return     the filter definition, if any matching one is registered.
 559  *             NULL if none found.
 560  */
 561 AVFilter *avfilter_get_by_name(const char *name);
 562
 563 /**
 564  * Create a filter instance.
 565  * @param filter    the filter to create an instance of
 566  * @param inst_name Name to give to the new instance.  Can be NULL for none.
 567  * @return          Pointer to the new instance on success.  NULL on failure.
 568  */
 569 AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name);
 570
 571 /**
 572  * Initialize a filter.
 573  * @param filter the filter to initialize
 574  * @param args   A string of parameters to use when initializing the filter.
 575  *               The format and meaning of this string varies by filter.
 576  * @param opaque Any extra non-string data needed by the filter.  The meaning
 577  *               of this parameter varies by filter.
 578  * @return       zero on success
 579  */
 580 int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque);
 581
 582 /**
 583  * Destroy a filter.
 584  * @param filter the filter to destroy
 585  */
 586 void avfilter_destroy(AVFilterContext *filter);
 587
 588 /**
 589  * Insert a filter in the middle of an existing link.
 590  * @param link the link into which the filter should be inserted
 591  * @param filt the filter to be inserted
 592  * @param in   the input pad on the filter to connect
 593  * @param out  the output pad on the filter to connect
 594  * @return     zero on success
 595  */
 596 int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt,
 597                            unsigned in, unsigned out);
 598
 599 /**
 600  * Insert a new pad.
 601  * @param idx Insertion point.  Pad is inserted at the end if this point
 602  *            is beyond the end of the list of pads.
 603  * @param count Pointer to the number of pads in the list
 604  * @param padidx_off Offset within an AVFilterLink structure to the element
 605  *                   to increment when inserting a new pad causes link
 606  *                   numbering to change
 607  * @param pads Pointer to the pointer to the beginning of the list of pads
 608  * @param links Pointer to the pointer to the beginning of the list of links
 609  * @param newpad The new pad to add. A copy is made when adding.
 610  */
 611 void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off,
 612                          AVFilterPad **pads, AVFilterLink ***links,
 613                          AVFilterPad *newpad);
 614
 615 /** insert a new input pad for the filter */
 616 static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index,
 617                                          AVFilterPad *p)
 618 {
 619     avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad),
 620                         &f->input_pads, &f->inputs, p);
 621 }
 622
 623 /** insert a new output pad for the filter */
 624 static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index,
 625                                           AVFilterPad *p)
 626 {
 627     avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad),
 628                         &f->output_pads, &f->outputs, p);
 629 }
 630
 631 #endif  /* AVFILTER_AVFILTER_H */