@param ctx uninitialized filter context to initialize
@param args Options to initialize the filter with. This must be a
':'-separated list of options in the 'key=value' form.
May be NULL if the options have been set directly using the
AVOptions API or there are no options that need to be set.
@return 0 on success, a negative AVERROR on failure
Initialize a filter with the supplied parameters.
@param ctx uninitialized filter context to initialize @param args Options to initialize the filter with. This must be a ':'-separated list of options in the 'key=value' form. May be NULL if the options have been set directly using the AVOptions API or there are no options that need to be set. @return 0 on success, a negative AVERROR on failure