[linux-audio-dev] Additional chunks in WAV files with libsndfile ?

Paul Davis paul at linuxaudiosystems.com
Mon Jan 23 18:20:51 EST 2006


On Tue, 2006-01-24 at 00:08 +0100, fons adriaensen wrote:
> On Tue, Jan 24, 2006 at 09:02:23AM +1100, Erik de Castro Lopo wrote:
> > fons adriaensen wrote:
> > 
> > > What I need in particular is some way to calibrate the time 
> > > axis - i.e. to say frame #N corresponds to t = 0, and some
> > > other similar info, mostly sample indices.
> > 
> > There is no existing chunk type which does what you require. In
> > addition, it would be a bad idea to define your own custom
> > chunk type to do this.
> 
> Would it ? It solves the problem, and all other apps will - or
> at least _should_ according to the WAV spec - just ignore it.
> What problems would be created by adding a new chunk ?
> The alternative would be a format that isn't standard at all.

BWF supports such a timestamp (the origination time).

> > However, it would be possible to add a comment string containing
> > the data you require as a text string. See:
> > 
> >     http://www.mega-nerd.com/libsndfile/api.html#string
> 
> Yes, been there before I posted. It's probably a matter of taste,
> but I don't find this much cleaner than adding a new chunk.
> 
> Thanks for the suggestions !
> 



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