From 13ff8fd01c4d2c1bada5c2e62881aed7c73c7b4d Mon Sep 17 00:00:00 2001 From: Vitor Sessak Date: Fri, 15 Feb 2008 22:13:40 +0000 Subject: [PATCH] Add many new and improve existing doxy comments. Commited in SoC by Bobby Bingham on 2007-08-14 16:39:26 Originally committed as revision 12095 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavfilter/avfilter.h | 254 +++++++++++++++++++++++++++++++++-------- 1 file changed, 207 insertions(+), 47 deletions(-) diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h index b0f41a9449..7c6b3616b7 100644 --- a/libavfilter/avfilter.h +++ b/libavfilter/avfilter.h @@ -39,12 +39,20 @@ typedef struct AVFilterPad AVFilterPad; */ typedef struct AVFilterPic { - uint8_t *data[4]; - int linesize[4]; ///< number of bytes per line - enum PixelFormat format; + uint8_t *data[4]; ///< picture data for each plane + int linesize[4]; ///< number of bytes per line + enum PixelFormat format; ///< colorspace - unsigned refcount; + 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; @@ -58,10 +66,11 @@ typedef struct AVFilterPic */ typedef struct AVFilterPicRef { - AVFilterPic *pic; - uint8_t *data[4]; - int linesize[4]; - int w, h; + 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 milliseconds @@ -74,9 +83,11 @@ typedef struct 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 + * @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); @@ -87,11 +98,15 @@ AVFilterPicRef *avfilter_ref_pic(AVFilterPicRef *ref, int pmask); */ void avfilter_unref_pic(AVFilterPicRef *ref); +/** + * A filter pad used for either input or output + */ struct AVFilterPad { /** - * Pad name. The name is unique among inputs and among oututs, but an - * input may have the same name as an output. + * 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. */ char *name; @@ -100,12 +115,17 @@ struct AVFilterPad * add audio in the future. */ int type; -#define AV_PAD_VIDEO 0 +#define AV_PAD_VIDEO 0 ///< video pad /** * Callback to get a list of supported formats. The returned list should - * be terminated by -1. This is used for both input and output pads and - * is required for both. + * be terminated by -1 (see avfilter_make_format_list for an easy way to + * create such a list). + * + * This is used for both input and output pads. If ommitted from an output + * pad, it is assumed that the only format supported is the same format + * that is being used for the filter's first input. If the filter has no + * inputs, then this may not be ommitted for its output pads. */ int *(*query_formats)(AVFilterLink *link); @@ -113,12 +133,16 @@ struct AVFilterPad * 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. Only required for input video pads. + * handle buffer requests. + * + * Input video pads only. */ AVFilterPicRef *(*get_video_buffer)(AVFilterLink *link, int perms); @@ -126,48 +150,69 @@ struct AVFilterPad * 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. Only required for input video pads. + * and should do its processing. + * + * Input video pads only. */ void (*draw_slice)(AVFilterLink *link, uint8_t *data[4], int y, int height); /** * Frame request callback. A call to this should result in at least one - * frame being output over the given link. Video output pads only. + * 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. NOTE: this should not set the format - * property - that is negotiated between filters by the filter system using - * the query_formats() callback. + * 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); }; -/* the default implementations of filter entry points */ +/** 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 query_formats() for video outputs */ int *avfilter_default_query_output_formats(AVFilterLink *link); +/** Default handler for get_video_buffer() for video inputs */ AVFilterPicRef *avfilter_default_get_video_buffer(AVFilterLink *link, int perms); +/** + * Filter definition. This defines the pads a filter contains, and all the + * callback functions used to interact with the filter. + */ typedef struct { - char *name; - char *author; + char *name; ///< filter name + char *author; ///< filter author - int priv_size; + int priv_size; ///< size of private data to allocate for the filter /** * Filter initialization function. Args contains the user-supplied @@ -176,69 +221,184 @@ typedef struct * 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); - const AVFilterPad *inputs; /// NULL terminated list of inputs. NULL if none - const AVFilterPad *outputs; /// NULL terminated list of outputs. NULL if none + 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; + AVClass *av_class; ///< Needed for av_log() - AVFilter *filter; + AVFilter *filter; ///< The AVFilter of which this is an instance - char *name; + char *name; ///< name of this filter instance - unsigned input_count; - AVFilterPad *input_pads; - AVFilterLink **inputs; + 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; - AVFilterPad *output_pads; - AVFilterLink **outputs; + unsigned output_count; ///< number of output pads + AVFilterPad *output_pads; ///< array of output pads + AVFilterLink **outputs; ///< array of pointers to output links - void *priv; + 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; - unsigned int srcpad; + AVFilterContext *src; ///< source filter + unsigned int srcpad; ///< index of the output pad on the source filter - AVFilterContext *dst; - unsigned int dstpad; + AVFilterContext *dst; ///< dest filter + unsigned int dstpad; ///< index of the input pad on the dest filter - int w, h; - enum PixelFormat format; + int w; ///< agreed upon image width + int h; ///< agreed upon image height + enum PixelFormat format; ///< agreed upon image colorspace AVFilterPicRef *cur_pic; AVFilterPicRef *outpic; }; -/** Link two filters together */ +/** + * 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); -/** Configure the colorspace, dimensions, etc of a link */ +/** + * Negotiate the colorspace, dimensions, etc of a link + * @param link The link to negotiate the properties of + * @return Zero on successful negotiation + */ int avfilter_config_link(AVFilterLink *link); +/** + * 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); + +/** + * Notofy 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 data Start of the picture data for this slice + * @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, uint8_t *data[4], 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 create an instance of + * this filter by name later with avfilter_create_by_name. A filter can still + * by created with acfilter_create 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(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_create(AVFilter *filter, char *inst_name); + +/** + * Creates a filter instace + * @param name The name of the filter type which is to be instantiated + * @param inst_name Name to give to the new instance. Can be NULL for none. + * @return Pointer to the new instance on success. NULL in failure. + */ AVFilterContext *avfilter_create_by_name(char *name, 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); +/** + * Helper function to create a list of supported formats. This is intended + * for use in AVFilterPad->query_formats(). + * @param len The number of formats supported + * @param ... A list of the supported formats + * @return The format list in a form suitable for returning from + * AVFilterPad->query_formats() + */ int *avfilter_make_format_list(int len, ...); /**