- */
-void avfilter_unref_buffer(AVFilterBufferRef *ref);
-
-/**
- * A list of supported formats for one end of a filter link. This is used
- * during the format negotiation process to try to pick the best format to
- * use to minimize the number of necessary conversions. Each filter gives a
- * list of the formats supported by each input and output pad. The list
- * given for each pad need not be distinct - they may be references to the
- * same list of formats, as is often the case when a filter supports multiple
- * formats, but will always output the same format as it is given in input.
- *
- * In this way, a list of possible input formats and a list of possible
- * output formats are associated with each link. When a set of formats is
- * negotiated over a link, the input and output lists are merged to form a
- * new list containing only the common elements of each list. In the case
- * that there were no common elements, a format conversion is necessary.
- * Otherwise, the lists are merged, and all other links which reference
- * either of the format lists involved in the merge are also affected.
- *
- * For example, consider the filter chain:
- * filter (a) --> (b) filter (b) --> (c) filter
- *
- * where the letters in parenthesis indicate a list of formats supported on
- * the input or output of the link. Suppose the lists are as follows:
- * (a) = {A, B}
- * (b) = {A, B, C}
- * (c) = {B, C}
- *
- * First, the first link's lists are merged, yielding:
- * filter (a) --> (a) filter (a) --> (c) filter
- *
- * Notice that format list (b) now refers to the same list as filter list (a).
- * Next, the lists for the second link are merged, yielding:
- * filter (a) --> (a) filter (a) --> (a) filter
- *
- * where (a) = {B}.
- *
- * Unfortunately, when the format lists at the two ends of a link are merged,
- * we must ensure that all links which reference either pre-merge format list
- * get updated as well. Therefore, we have the format list structure store a
- * pointer to each of the pointers to itself.
- */
-typedef struct AVFilterFormats {
- unsigned format_count; ///< number of formats
- int *formats; ///< list of media formats
-
- unsigned refcount; ///< number of references to this list
- struct AVFilterFormats ***refs; ///< references to this list
-} AVFilterFormats;
-
-/**
- * Create a list of supported formats. This is intended for use in
- * AVFilter->query_formats().
- *
- * @param fmts list of media formats, terminated by -1
- * @return the format list, with no existing references
- */
-AVFilterFormats *avfilter_make_format_list(const int *fmts);
-
-/**
- * Add fmt to the list of media formats contained in *avff.
- * If *avff is NULL the function allocates the filter formats struct
- * and puts its pointer in *avff.
- *
- * @return a non negative value in case of success, or a negative
- * value corresponding to an AVERROR code in case of error
- */
-int avfilter_add_format(AVFilterFormats **avff, int fmt);
-
-/**
- * Return a list of all formats supported by Libav for the given media type.
- */
-AVFilterFormats *avfilter_all_formats(enum AVMediaType type);
-
-/**
- * Return a format list which contains the intersection of the formats of
- * a and b. Also, all the references of a, all the references of b, and
- * a and b themselves will be deallocated.