With 3.07 .dash.m4v left behind

[Ralph Corderoy]

Hi Richard,

> { unlink( $audio_file, $video_file ); }
> acts on two files together.

That's fine.  If removing either of those fails then unlink returns
false, setting `$!' to an error.  You only need to do them separately if
you want to determine which had the error, and collect possibly
different reasons for the errors.

This problem and the other rename one look to be race conditions inside
ffmpeg;  I'm suggesting it exits allowing get_iplayer to continue before
all of ffmpeg's threads have finished so some of the files it had open
are still open.  As a race condition, it isn't likely to be trivially
repeatable, e.g. same PID.

Examination of ffmpeg might show this is possible.  There may be ffmpeg
bugs already reported on it.  And I suspect Process Monitor or something
similar could track the file and thread activity across all the
processes so post-inspection can confirm;  but that's Windows and I
don't know it.

-- 
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy