libavformat/movenc.c:2722: error: Uninitialized Value
  The value read from duration was never initialized.

libavformat/movenc.c:2722:9: 
2720.         }
2721.         avio_wb32(pb, (0 << 31) | (ref_size & 0x7fffffff)); /* reference_type (0 = media) | referenced_size */
2722.         avio_wb32(pb, duration); /* subsegment_duration */
              ^
2723.         avio_wb32(pb, (starts_with_SAP << 31) | (0 << 28) | 0); /* starts_with_SAP | SAP_type | SAP_delta_time */
2724.     }
