A few ffmpeg queries

[Vangelis forthnet]

 On Thu Sep 7 22:19:48 BST 2017, RS wrote: 

> As far as I am aware 
> all the variants Vangelis suggested work.

 Yes they do, with fairly recent FFmpeg versions  
that are also backward compatible...  

 However, the GiP perl script must cater for a variety 
of OSes and in the case of Linux distros some (still) 
come by default with older FFmpeg packages; 
the more recent 

-c:v copy -c:a copy 

syntax/iteration isn't recognised by those older FFmpeg versions, 
so issuing "--ffmpeg-obsolete" in your terminal ("ffmpegobsolete 1" 
inside options) will revert to the legacy syntax; from help: 

> --ffmpeg-obsolete  
> 
> Indicates you are using an obsolete version of ffmpeg (<1.0) 
> that may not support certain options. 
> Without this option, MP4 conversion may fail 
> with obsolete versions of ffmpeg.

 As hinted, "--ffmpeg-obsolete" also takes care of some 
other ffmpeg switches (e.g. verbosity level), browse the 
actual code and ye shall find... 

Many greetings, 
Vangelis.