Duration not works

If i set duration same as original video that happened
`E/TranscodeEngine(12943): Unexpected error while transcoding.
E/TranscodeEngine(12943): java.lang.NullPointerException: Attempt to invoke virtual method 'java.nio.ByteBuffer java.nio.ByteBuffer.asReadOnlyBuffer()' on a null object reference`

if i set duration less than original video but close to original it returns total bullshit for example i set 10 seconds for 12 secs video and than it returns 2 seconds video.