Re: Video narration

[Paul Garlick]

Hi Laura and All,

I have determined the cause of the playback problems with Firefox and
pushed a fix to the  videos.git repository.

Essentially, a limitation of the treatment of opus audio streams in
Firefox means that videos with gaps in the audio stream are not played
properly.

There were two parts to the fix.  First, the audio streams need to be
padded with silence to match the duration of the video streams.  Then,
the concatenation of the audio streams needs to be done separately from
the video streams.  The two streams are the same duration and may be
joined without re-encoding.

A consequence of the new approach is that the cli sessions need to be
checked to ensure that the duration of the video streams are (slightly)
longer than the audio streams.  Otherwise, the audio streams will be
truncated.  

I have made a start with the 01-installation-from-script video.  I am
using Firefox version 66.0.3 to test.

Can others confirm that the new method works with their browsers and
players? 

Best regards,

Paul.