+filter_chain_AppendFilter
+filter_chain_AppendFromString
+filter_chain_AudioFilter
+filter_chain_Delete
+filter_chain_DeleteFilter
+filter_chain_GetFilter
+filter_chain_GetFmtOut
+filter_chain_GetLength
+__filter_chain_New
+filter_chain_Reset
+filter_chain_SubFilter
+filter_chain_VideoFilter