Document filter chain API.

include/vlc_filter.h

@@ -35,7 +35,7 @@
 typedef struct filter_owner_sys_t filter_owner_sys_t;
 
 /** Structure describing a filter
- * @warning BIG FAT WARNING : the code relies in the first 4 members of
+ * @warning BIG FAT WARNING : the code relies on the first 4 members of
  * filter_t and decoder_t to be the same, so if you have anything to add,
  * do it at the end of the structure.
  */
@@ -95,6 +95,9 @@ struct filter_t
  * buffer. You have to release it using filter_DeletePicture or by returning
  * it to the caller as a pf_video_filter return value.
  * Provided for convenience.
+ *
+ * \param p_filter filter_t object
+ * \return new picture on success or NULL on failure
  */
 static inline picture_t *filter_NewPicture( filter_t *p_filter )
 {
@@ -107,6 +110,9 @@ static inline picture_t *filter_NewPicture( filter_t *p_filter )
 /**
  * This function will release a picture create by filter_NewPicture.
  * Provided for convenience.
+ *
+ * \param p_filter filter_t object
+ * \param p_picture picture to be deleted
  */
 static inline void filter_DeletePicture( filter_t *p_filter, picture_t *p_picture )
 {
@@ -118,6 +124,9 @@ static inline void filter_DeletePicture( filter_t *p_filter, picture_t *p_pictur
  * buffer. You have to release it using filter_DeleteSubpicture or by returning
  * it to the caller as a pf_sub_filter return value.
  * Provided for convenience.
+ *
+ * \param p_filter filter_t object
+ * \return new subpicture
  */
 static inline subpicture_t *filter_NewSubpicture( filter_t *p_filter )
 {
@@ -130,6 +139,9 @@ static inline subpicture_t *filter_NewSubpicture( filter_t *p_filter )
 /**
  * This function will release a subpicture create by filter_NewSubicture.
  * Provided for convenience.
+ *
+ * \param p_filter filter_t object
+ * \param p_subpicture to be released
  */
 static inline void filter_DeleteSubpicture( filter_t *p_filter, subpicture_t *p_subpicture )
 {
@@ -141,6 +153,10 @@ static inline void filter_DeleteSubpicture( filter_t *p_filter, subpicture_t *p_
  * output buffer. You have to release it using block_Release or by returning
  * it to the caller as a pf_audio_filter return value.
  * Provided for convenience.
+ *
+ * \param p_filter filter_t object
+ * \param i_size size of audio buffer requested
+ * \return block to be used as audio output buffer
  */
 static inline block_t *filter_NewAudioBuffer( filter_t *p_filter, int i_size )
 {
@@ -150,7 +166,6 @@ static inline block_t *filter_NewAudioBuffer( filter_t *p_filter, int i_size )
     return p_block;
 }
 
-
 /**
  * Create a picture_t *(*)( filter_t *, picture_t * ) compatible wrapper
  * using a void (*)( filter_t *, picture_t *, picture_t * ) function
@@ -178,28 +193,127 @@ static inline block_t *filter_NewAudioBuffer( filter_t *p_filter, int i_size )
 
 /**
  * Filter chain management API
+ * The filter chain management API is used to dynamically construct filters
+ * and add them in a chain.
  */
 
 typedef struct filter_chain_t filter_chain_t;
 
+/**
+ * Create new filter chain
+ *
+ * \param p_object pointer to a vlc object
+ * \param psz_capability vlc capability of filters in filter chain
+ * \param b_allow_format_fmt_change allow changing of fmt
+ * \param pf_buffer_allocation_init callback function to initialize buffer allocations
+ * \param pf_buffer_allocation_clear callback function to clear buffer allocation initialization
+ * \param p_buffer_allocation_data pointer to private allocation data
+ * \return pointer to a filter chain
+ */
 VLC_EXPORT( filter_chain_t *, __filter_chain_New, ( vlc_object_t *, const char *, bool, int (*)( filter_t *, void * ), void (*)( filter_t * ), void *  ) );
 #define filter_chain_New( a, b, c, d, e, f ) __filter_chain_New( VLC_OBJECT( a ), b, c, d, e, f )
+
+/**
+ * Delete filter chain will delete all filters in the chain and free all
+ * allocated data. The pointer to the filter chain is then no longer valid.
+ *
+ * \param p_chain pointer to filter chain
+ */
 VLC_EXPORT( void, filter_chain_Delete, ( filter_chain_t * ) );
+
+/**
+ * Reset filter chain will delete all filters in the chain and
+ * reset p_fmt_in and p_fmt_out to the new values.
+ *
+ * \param p_chain pointer to filter chain
+ * \param p_fmt_in new fmt_in params
+ * \param p_fmt_out new fmt_out params
+ */
 VLC_EXPORT( void, filter_chain_Reset, ( filter_chain_t *, const es_format_t *, const es_format_t * ) );
 
+/**
+ * Append filter to the end of the chain.
+ *
+ * \param p_chain pointer to filter chain
+ * \param psz_name name of filter
+ * \param p_cfg
+ * \param p_fmt_in input es_format_t
+ * \param p_fmt_out output es_format_t
+ * \return pointer to filter chain
+ */
 VLC_EXPORT( filter_t *, filter_chain_AppendFilter, ( filter_chain_t *, const char *, config_chain_t *, const es_format_t *, const es_format_t * ) );
+
+/**
+ * Append new filter to filter chain from string.
+ *
+ * \param p_chain pointer to filter chain
+ * \param psz_string string of filters
+ * \return 0 for success
+ */
 VLC_EXPORT( int, filter_chain_AppendFromString, ( filter_chain_t *, const char * ) );
+
+/**
+ * Delete filter from filter chain. This function also releases the filter
+ * object and unloads the filter modules. The pointer to p_filter is no
+ * longer valid after this function successfully returns.
+ *
+ * \param p_chain pointer to filter chain
+ * \param p_filter pointer to filter object
+ * \return VLC_SUCCESS on succes, else VLC_EGENERIC
+ */
 VLC_EXPORT( int, filter_chain_DeleteFilter, ( filter_chain_t *, filter_t * ) );
 
+/**
+ * Get filter by name of position in the filter chain.
+ *
+ * \param p_chain pointer to filter chain
+ * \param i_position position of filter in filter chain
+ * \param psz_name name of filter to get
+ * \return filter object based on position or name provided
+ */
 VLC_EXPORT( filter_t *, filter_chain_GetFilter, ( filter_chain_t *, int, const char * ) );
+
+/**
+ * Get the number of filters in the filter chain.
+ *
+ * \param p_chain pointer to filter chain
+ * \return number of filters in this filter chain
+ */
 VLC_EXPORT( int, filter_chain_GetLength, ( filter_chain_t * ) );
+
+/**
+ * Get last p_fmt_out in the chain.
+ *
+ * \param p_chain pointer to filter chain
+ * \return last p_fmt (es_format_t) of this filter chain
+ */
 VLC_EXPORT( const es_format_t *, filter_chain_GetFmtOut, ( filter_chain_t * ) );
 
 /**
- * Apply the filter chain
+ * Apply the filter chain to a video picture.
+ *
+ * \param p_chain pointer to filter chain
+ * \param p_picture picture to apply filters on
+ * \return modified picture after applying all video filters
  */
 VLC_EXPORT( picture_t *, filter_chain_VideoFilter, ( filter_chain_t *, picture_t * ) );
+
+/**
+ * Apply the filter chain to a audio block.
+ *
+ * \param p_chain pointer to filter chain
+ * \param p_block audio frame to apply filters on
+ * \return modified audio frame after applying all audio filters
+ */
 VLC_EXPORT( block_t *, filter_chain_AudioFilter, ( filter_chain_t *, block_t * ) );
+
+/**
+ * Apply filter chain to subpictures.
+ *
+ * \param p_chain pointer to filter chain
+ * \param display_date of subpictures
+ */
 VLC_EXPORT( void, filter_chain_SubFilter, ( filter_chain_t *, mtime_t ) );
 
 #endif /* _VLC_FILTER_H */
+