fixup for #3081

* dont write the "sbpg" box in video tracks

app/src/main/java/org/schabi/newpipe/streams/Mp4FromDashWriter.java

@@ -291,8 +291,10 @@ public class Mp4FromDashWriter {
                 sampleCount[i] = 1;// the index is not base zero
                 sampleExtra[i] = -1;
             }
+            if (tablesInfo[i].sbgp > 0) {
                 writeEntryArray(tablesInfo[i].sbgp, 1, sampleCount[i]);
             }
+        }
 
         if (auxBuffer == null) {
             outRestore();