Re: Video narration

[Paul Garlick]

Hi Laura,

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

> Ok I will go on with the followings then!

Working on the timings for 02-daily-use1 I have found that I have
needed to make a couple of changes to the 'hesitate' procedure in the
screen script.  I have been finding that the pause introduced by the
sleep command is not accurate, making it difficult to set the right
values in the sessions files.

I wonder whether you have noticed the same effect?

To improve the accuracy I have changed the procedure definition to use
a scaling factor of one thousand, to go from milliseconds to
microseconds, and have increased the chunk size to 2 ms.  The Guile
documentation for usleep notes that many systems round the interval
specified up or down and are unable to achieve accuracy to the
microsecond level.  

After some testing on the system I am using to build the videos I found
that 2 ms was the optimum value.  With this value '#:sleep 30000', for
example, produces a pause of 30 s.

I will commit the change so that you can test it too.  If we keep the
change it will mean re-checking the timings in the session files. 
However, I think that this will be necessary to make the adjustments in
the total durations for Firefox.

Best regards,

Paul.