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