Transcode result not properly seekable
I've used the "Convert & Stream" GUI on macOS (with the Video - VP80 + Vorbis (WebM)) preset. It worked fine, showed progress as expected using the playback position indicator.
But the resulting file does not seek properly in VLC and it shows a duration of 54:31:12, which is wrong.
Original file: http://streams.videolan.org/issues/17855/multi-opengl-demo.mov
Transcoding result: http://streams.videolan.org/issues/17988/Fooo.webm