A class for the private data, used to declare filter private AVOptions.
This field is NULL for filters that do not declare any options.
If this field is non-NULL, the first member of the filter private data
must be a pointer to AVClass, which will be set by libavfilter generic
code to this class.
A class for the private data, used to declare filter private AVOptions. This field is NULL for filters that do not declare any options.
If this field is non-NULL, the first member of the filter private data must be a pointer to AVClass, which will be set by libavfilter generic code to this class.