[FFmpeg-cvslog] r12095 - trunk/libavfilter/avfilter.h
vitor
subversion
Fri Feb 15 23:13:40 CET 2008
Author: vitor
Date: Fri Feb 15 23:13:40 2008
New Revision: 12095
Log:
Add many new and improve existing doxy comments.
Commited in SoC by Bobby Bingham on 2007-08-14 16:39:26
Modified:
trunk/libavfilter/avfilter.h
Modified: trunk/libavfilter/avfilter.h
==============================================================================
--- trunk/libavfilter/avfilter.h (original)
+++ trunk/libavfilter/avfilter.h Fri Feb 15 23:13:40 2008
@@ -39,12 +39,20 @@ typedef struct AVFilterPad AVFilterP
*/
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(AVFilte
*/
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, ...);
/**
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