/* * Filter layer * copyright (c) 2007 Bobby Bingham * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef FFMPEG_AVFILTER_H #define FFMPEG_AVFILTER_H #include #include "avcodec.h" typedef struct AVFilterContext AVFilterContext; typedef struct AVFilterLink AVFilterLink; typedef struct AVFilterPad AVFilterPad; /* TODO: look for other flags which may be useful in this structure (interlace * flags, etc) */ /** * A reference-counted picture data type used by the filter system. Filters * should not store pointers to this structure directly, but instead use the * AVFilterPicRef structure below */ typedef struct AVFilterPic { uint8_t *data[4]; ///< picture data for each plane int linesize[4]; ///< number of bytes per line enum PixelFormat format; ///< colorspace unsigned refcount; ///< number of references to this image /** private data to be used by a custom free function */ void *priv; /** * A pointer to the function to deallocate this image if the default * function is not sufficient. This could, for example, add the memory * back into a memory pool to be reused later without the overhead of * reallocating it from scratch. */ void (*free)(struct AVFilterPic *pic); } AVFilterPic; /** * A reference to an AVFilterPic. Since filters can manipulate the origin of * a picture to, for example, crop image without any memcpy, the picture origin * and dimensions are per-reference properties. Linesize is also useful for * image flipping, frame to field filters, etc, and so is also per-reference. * * TODO: add anything necessary for frame reordering */ typedef struct AVFilterPicRef { AVFilterPic *pic; ///< the picture that this is a reference to uint8_t *data[4]; ///< picture data for each plane int linesize[4]; ///< number of bytes per line int w; ///< image width int h; ///< image height int64_t pts; ///< presentation timestamp in units of 1/AV_TIME_BASE AVRational pixel_aspect; ///< pixel aspect ratio int perms; ///< permissions #define AV_PERM_READ 0x01 ///< can read from the buffer #define AV_PERM_WRITE 0x02 ///< can write to the buffer #define AV_PERM_PRESERVE 0x04 ///< nobody else can overwrite the buffer #define AV_PERM_REUSE 0x08 ///< can output the buffer multiple times, with the same contents each time #define AV_PERM_REUSE2 0x10 ///< can output the buffer multiple times, modified each time } AVFilterPicRef; /** * Add a new reference to a picture. * @param ref An existing reference to the picture * @param pmask A bitmask containing the allowable permissions in the new * reference * @return A new reference to the picture with the same properties as the * old, excluding any permissions denied by pmask */ AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask); /** * Remove a reference to a picture. If this is the last reference to the * picture, the picture itself is also automatically freed. * @param ref Reference to the picture. */ void avfilter_unref_pic(AVFilterPicRef *ref); /** * A list of supported formats for one end of a filter link. This is used * during the format negotiation process to try to pick the best format to * use to minimize the number of necessary conversions. Each filter gives a * list of the formats supported by each input and output pad. The list * given for each pad need not be distinct - they may be references to the * same list of formats, as is often the case when a filter supports multiple * formats, but will always outut the same format as it is given in input. * * In this way, a list of possible input formats and a list of possible * output formats are associated with each link. When a set of formats is * negotiated over a link, the input and output lists are merged to form a * new list containing only the common elements of each list. In the case * that there were no common elements, a format conversion is necessary. * Otherwise, the lists are merged, and all other links which reference * either of the format lists involved in the merge are also affected. * * For example, consider the filter chain: * filter (a) --> (b) filter (b) --> (c) filter * * where the letters in parenthesis indicate a list of formats supported on * the input or output of the link. Suppose the lists are as follows: * (a) = {A, B} * (b) = {A, B, C} * (c) = {B, C} * * First, the first link's lists are merged, yielding: * filter (a) --> (a) filter (a) --> (c) filter * * Notice that format list (b) now refers to the same list as filter list (a). * Next, the lists for the second link are merged, yielding: * filter (a) --> (a) filter (a) --> (a) filter * * where (a) = {B}. * * Unfortunately, when the format lists at the two ends of a link are merged, * we must ensure that all links which reference either pre-merge format list * get updated as well. Therefore, we have the format list structure store a * pointer to each of the pointers to itself. */ typedef struct AVFilterFormats AVFilterFormats; struct AVFilterFormats { unsigned format_count; ///< number of formats int *formats; ///< list of formats unsigned refcount; ///< number of references to this list AVFilterFormats ***refs; ///< references to this list }; /** * Helper function to create a list of supported formats. This is intended * for use in AVFilter->query_formats(). * @param len The number of formats supported * @param ... A list of the supported formats * @return The format list, with no existing references */ AVFilterFormats *avfilter_make_format_list(int len, ...); /** * Returns a fairly comprehensive list of colorspaces which are supported by * many of the included filters. This is not truly "all" the colorspaces, but * it is most of them, and it is the most commonly supported large subset. */ AVFilterFormats *avfilter_all_colorspaces(void); /** * If a and b share at least one common format, they are merged into a new * format list which is returned. All the references to a and b are updated * to point to this new list, and a and b are deallocated. * * If a and b do not share any common formats, neither is modified, and NULL * is returned. */ AVFilterFormats *avfilter_merge_formats(AVFilterFormats *a, AVFilterFormats *b); /** Adds *ref as a new reference to f */ void avfilter_formats_ref(AVFilterFormats *f, AVFilterFormats **ref); /** * Remove *ref as a reference to the format list it currently points to, * deallocate that list if this was the last reference, and set *ref to NULL */ void avfilter_formats_unref(AVFilterFormats **ref); int avfilter_poll_frame(AVFilterLink *link); /** * A filter pad used for either input or output */ struct AVFilterPad { /** * Pad name. The name is unique among inputs and among outputs, but an * input may have the same name as an output. This may be NULL if this * pad has no need to ever be referenced by name. */ const char *name; /** * AVFilterPad type. Only video supported now, hopefully someone will * add audio in the future. */ int type; #define AV_PAD_VIDEO 0 ///< video pad /** * Minimum required permissions on incoming buffers. Any buffers with * insufficient permissions will be automatically copied by the filter * system to a new buffer which provides the needed access permissions. * * Input pads only. */ int min_perms; /** * Permissions which are not accepted on incoming buffers. Any buffer * which has any of these permissions set be automatically copied by the * filter system to a new buffer which does not have those permissions. * This can be used to easily disallow buffers with AV_PERM_REUSE. * * Input pads only. */ int rej_perms; /** * Callback called before passing the first slice of a new frame. If * NULL, the filter layer will default to storing a reference to the * picture inside the link structure. * * Input video pads only. */ void (*start_frame)(AVFilterLink *link, AVFilterPicRef *picref); /** * Callback function to get a buffer. If NULL, the filter system will * handle buffer requests. * * Input video pads only. */ AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms); /** * Callback called after the slices of a frame are completely sent. If * NULL, the filter layer will default to releasing the reference stored * in the link structure during start_frame(). * * Input video pads only. */ void (*end_frame)(AVFilterLink *link); /** * Slice drawing callback. This is where a filter receives video data * and should do its processing. * * Input video pads only. */ void (*draw_slice)(AVFilterLink *link, int y, int height); /** * Frame poll callback. This returns the number of immediately available * frames. It should return a positive value if the next request_frame() * is guaranteed to return one frame (with no delay). * * Defaults to just calling the source poll_frame() method. * * Output video pads only. */ int (*poll_frame)(AVFilterLink *link); /** * Frame request callback. A call to this should result in at least one * frame being output over the given link. This should return zero on * success, and another value on error. * * Output video pads only. */ int (*request_frame)(AVFilterLink *link); /** * Link configuration callback. * * For output pads, this should set the link properties such as * width/height. This should NOT set the format property - that is * negotiated between filters by the filter system using the * query_formats() callback before this function is called. * * For input pads, this should check the properties of the link, and update * the filter's internal state as necessary. * * For both input and output filters, this should return zero on success, * and another value on error. */ int (*config_props)(AVFilterLink *link); }; /** Default handler for start_frame() for video inputs */ void avfilter_default_start_frame(AVFilterLink *link, AVFilterPicRef *picref); /** Default handler for end_frame() for video inputs */ void avfilter_default_end_frame(AVFilterLink *link); /** Default handler for config_props() for video outputs */ int avfilter_default_config_output_link(AVFilterLink *link); /** Default handler for config_props() for video inputs */ int avfilter_default_config_input_link (AVFilterLink *link); /** Default handler for get_video_buffer() for video inputs */ AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link, int perms); /** * A helper for query_formats() which sets all links to the same list of * formats. If there are no links hooked to this filter, the list of formats is * freed. */ void avfilter_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats); /** Default handler for query_formats() */ int avfilter_default_query_formats(AVFilterContext *ctx); void avfilter_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref); /** * Filter definition. This defines the pads a filter contains, and all the * callback functions used to interact with the filter. */ typedef struct { const char *name; ///< filter name const char *author; ///< filter author int priv_size; ///< size of private data to allocate for the filter /** * Filter initialization function. Args contains the user-supplied * parameters. FIXME: maybe an AVOption-based system would be better? * opaque is data provided by the code requesting creation of the filter, * and is used to pass data to the filter. */ int (*init)(AVFilterContext *ctx, const char *args, void *opaque); /** * Filter uninitialization function. Should deallocate any memory held * by the filter, release any picture references, etc. This does not need * to deallocate the AVFilterContext->priv memory itself. */ void (*uninit)(AVFilterContext *ctx); /** * Query formats supported by the filter and its pads. Should set the * in_formats for links connected to its output pads, and out_formats * for links connected to its input pads. * * Should return zero on success. */ int (*query_formats)(AVFilterContext *); const AVFilterPad *inputs; ///< NULL terminated list of inputs. NULL if none const AVFilterPad *outputs; ///< NULL terminated list of outputs. NULL if none } AVFilter; /** An instance of a filter */ struct AVFilterContext { AVClass *av_class; ///< Needed for av_log() AVFilter *filter; ///< The AVFilter of which this is an instance char *name; ///< name of this filter instance unsigned input_count; ///< number of input pads AVFilterPad *input_pads; ///< array of input pads AVFilterLink **inputs; ///< array of pointers to input links unsigned output_count; ///< number of output pads AVFilterPad *output_pads; ///< array of output pads AVFilterLink **outputs; ///< array of pointers to output links void *priv; ///< private data for use by the filter }; /** * A links between two filters. This contains pointers to the source and * destination filters between which this link exists, and the indices of * the pads involved. In addition, this link also contains the parameters * which have been negotiated and agreed upon between the filter, such as * image dimensions, format, etc */ struct AVFilterLink { AVFilterContext *src; ///< source filter unsigned int srcpad; ///< index of the output pad on the source filter AVFilterContext *dst; ///< dest filter unsigned int dstpad; ///< index of the input pad on the dest filter /** stage of the initialization of the link properties (dimensions, etc) */ enum { AVLINK_UNINIT = 0, ///< not started AVLINK_STARTINIT, ///< started, but incomplete AVLINK_INIT ///< complete } init_state; int w; ///< agreed upon image width int h; ///< agreed upon image height enum PixelFormat format; ///< agreed upon image colorspace /** * Lists of formats supported by the input and output filters respectively. * These lists are used for negotiating the format to actually be used, * which will be loaded into the format member, above, when chosen. */ AVFilterFormats *in_formats; AVFilterFormats *out_formats; /** * The picture reference currently being sent across the link by the source * filter. This is used internally by the filter system to allow * automatic copying of pictures which d not have sufficient permissions * for the destination. This should not be accessed directly by the * filters. */ AVFilterPicRef *srcpic; AVFilterPicRef *cur_pic; AVFilterPicRef *outpic; }; /** * Link two filters together * @param src The source filter * @param srcpad Index of the output pad on the source filter * @param dst The destination filter * @param dstpad Index of the input pad on the destination filter * @return Zero on success */ int avfilter_link(AVFilterContext *src, unsigned srcpad, AVFilterContext *dst, unsigned dstpad); /** * Negotiate the colorspace, dimensions, etc of all inputs to a filter. * @param filter The filter to negotiate the properties for its inputs * @return Zero on successful negotiation */ int avfilter_config_links(AVFilterContext *filter); /** * Request a picture buffer with a specific set of permissions * @param link The output link to the filter from which the picture will * be requested * @param perms The required access permissions * @return A reference to the picture. This must be unreferenced with * avfilter_unref_pic when you are finished with it. */ AVFilterPicRef *avfilter_get_video_buffer(AVFilterLink *link, int perms); /** * Request an input frame from the filter at the other end of the link. * @param link The input link * @return Zero on success */ int avfilter_request_frame(AVFilterLink *link); /** * Notify the next filter of the start of a frame. * @param link The output link the frame will be sent over * @param picref A reference to the frame about to be sent. The data for this * frame need only be valid once draw_slice() is called for that * portion. The receiving filter will free this reference when * it no longer needs it. */ void avfilter_start_frame(AVFilterLink *link, AVFilterPicRef *picref); /** * Notify the next filter that the current frame has finished * @param link The output link the frame was sent over */ void avfilter_end_frame(AVFilterLink *link); /** * Send a slice to the next filter * @param link The output link over which the frame is being sent * @param y Offset in pixels from the top of the image for this slice * @param h Height of this slice in pixels */ void avfilter_draw_slice(AVFilterLink *link, int y, int h); /** Initialize the filter system. Registers all builtin filters */ void avfilter_init(void); /** Uninitialize the filter system. Unregisters all filters */ void avfilter_uninit(void); /** * Register a filter. This is only needed if you plan to use * avfilter_get_by_name later to lookup the AVFilter structure by name. A * filter can still by instantiated with avfilter_open even if it is not * registered. * @param filter The filter to register */ void avfilter_register(AVFilter *filter); /** * Gets a filter definition matching the given name * @param name The filter name to find * @return The filter definition, if any matching one is registered. * NULL if none found. */ AVFilter *avfilter_get_by_name(const char *name); /** * Create a filter instance * @param filter The filter to create an instance of * @param inst_name Name to give to the new instance. Can be NULL for none. * @return Pointer to the new instance on success. NULL on failure. */ AVFilterContext *avfilter_open(AVFilter *filter, const char *inst_name); /** * Initialize a filter * @param filter The filter to initialize * @param args A string of parameters to use when initializing the filter. * The format and meaning of this string varies by filter. * @param opaque Any extra non-string data needed by the filter. The meaning * of this parameter varies by filter. * @return Zero on success */ int avfilter_init_filter(AVFilterContext *filter, const char *args, void *opaque); /** * Destroy a filter * @param filter The filter to destroy */ void avfilter_destroy(AVFilterContext *filter); /** * Insert a filter in the middle of an existing link. * @param link The link into which the filter should be inserted * @param filt The filter to be inserted * @param in The input pad on the filter to connect * @param out The output pad on the filter to connect * @return Zero on success */ int avfilter_insert_filter(AVFilterLink *link, AVFilterContext *filt, unsigned in, unsigned out); /** * Insert a new pad * @param idx Insertion point. Pad is inserted at the end if this point * is beyond the end of the list of pads. * @param count Pointer to the number of pads in the list * @param padidx_off Offset within an AVFilterLink structure to the element * to increment when inserting a new pad causes link * numbering to change * @param pads Pointer to the pointer to the beginning of the list of pads * @param links Pointer to the pointer to the beginning of the list of links * @param newpad The new pad to add. A copy is made when adding. */ void avfilter_insert_pad(unsigned idx, unsigned *count, size_t padidx_off, AVFilterPad **pads, AVFilterLink ***links, AVFilterPad *newpad); /** insert a new input pad for the filter */ static inline void avfilter_insert_inpad(AVFilterContext *f, unsigned index, AVFilterPad *p) { avfilter_insert_pad(index, &f->input_count, offsetof(AVFilterLink, dstpad), &f->input_pads, &f->inputs, p); } /** insert a new output pad for the filter */ static inline void avfilter_insert_outpad(AVFilterContext *f, unsigned index, AVFilterPad *p) { avfilter_insert_pad(index, &f->output_count, offsetof(AVFilterLink, srcpad), &f->output_pads, &f->outputs, p); } #endif /* FFMPEG_AVFILTER_H */