* Frame request callback. A call to this should result in at least one
* frame being output over the given link. This should return zero on
* success, and another value on error.
+ * See avfilter_request_frame() for the error codes with a specific
+ * meaning.
*
* Output video pads only.
*/
* Request an input frame from the filter at the other end of the link.
*
* @param link the input link
- * @return zero on success
+ * @return zero on success or a negative error code; in particular:
+ * AVERROR_EOF means that the end of frames have been reached;
+ * AVERROR(EAGAIN) means that no frame could be immediately
+ * produced.
*/
int avfilter_request_frame(AVFilterLink *link);