Re: [SoX-users] Are existing tags retained when adding silence (pad)?

[Ulrich K. <ul...@ch...>]

Ron Leach <ron...@te...>:

> We're thinking of trying to use Sox to add silence to the beginning
> and end of each track.  The 'pad' effect, described in the
> documentation here http://sox.sourceforge.net/sox.html, would seem to
> do the trick.  The tracks are already tagged with Title, artist,
> composer etc, what happens to these 'tags' that are already in the
> music files if we run Sox to add 'pad's?  Are they retained, or does
> adding silence effectively create a new file without tags?

Generally, tags/comments are passed through from the first input file  
unless a change is requested (by the --add-comment, --comment,  
--comment-file options). SoX will add "Processed by SoX" (only) if  
there were no comments in the input file.

How this works out in practice depends on the capabilities of the file  
format and its SoX driver. The easiest way to check is probably trying.

(NB. If you are using a lossy file format, such as MP3, the audio data  
will be decoded, then re-encoded in the process, possibly leading to a  
sound degradation.)

Ulrich