diff --git a/internal/media/muxer.go b/internal/media/muxer.go
index c5d20ff..9d5e667 100644
--- a/internal/media/muxer.go
+++ b/internal/media/muxer.go
@@ -75,6 +75,10 @@ func Mux(muxer string, readers ...io.ReadCloser) (retval io.Reader) {
 			}
 
 			inputs[i] = input
+			if input.Ctx.StreamsCnt() > 1 {
+				err = errors.New("Too many streams found in input")
+				return
+			}
 
 			var stream *gmf.Stream
 			if stream, err = input.Ctx.GetStream(0); err != nil {