A few ffmpeg queries

[RS]

From: Vangelis forthnet
Sent: Friday, September 8, 2017 01:36

> 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,

I understand that.  If the old syntax works across the board and there is no 
threat to remove the old syntax there is no advantage in changing.  I 
actually prefer the old syntax because it is easier to type in that it does 
not require the use of the shift key for the :.

It is of course a different matter if the new syntax introduces new 
functionality.

I realise you did not write the code but are only defending it, but as a 
matter of style, readability and efficiency where a number of options are 
dependent on the same flag it is better to test the flag once and use a 
single if ... else statement with a block or compound statement or whatever 
Perl calls it to deal with all the options together rather than test the 
flag over and over again for each option.

>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...

As far as I am aware -loglevel is not a new ffmpeg option.  In any event in 
the interests of backward compatibility where possible the old should 
continue to work alongside the new.   Another difficulty is that as far as 
get_iplayer is concerned there is more than one level of ffmpeg 
obsolescence.  If I have remembered correctly v2.5 or above is needed for 
HLS and v3.0 or above is needed for DASH.  (Does that leave any modes 
obsolete versions will work with?)

Anyway it is a very minor point.

Best wishes
Richard