[Vorbis-dev] padding in comment header

[Ian Malone]

Kyungjoon Lee wrote:
> On 2/5/06, John Edwards <john.edwards33 at ntlworld.com> wrote:
> 
>>My 'oggenc2.8' has provided the option of adding padding to the header
>>for quite some considerable time, now. The source is at Rarewares, if
>>anyone is interested.
> 

I'd noticed it in passing, do you have a strategy for choosing padding
or is it user specified?  Is there a matching comment editor?

> 
> But your version of oggenc is the only program that I know which
> honours padding. Peter Pawlowski's in_vorbis used to support padding
> at some point, but only very briefly, and rather unsuccessfully, at
> that.
> 
> If you want this feature to catch on, the best way to see it happen
> would be to make sure the feature is available in the reference
> implementation; any/all of Xiph libvorbis, libvorbisfile,
> vorbiscomment, and oggenc.
> 

Support only really needs to be added in the encoder and the tag
editor.  The way decoding the header is specified a sane decoder
(including libvorbis+libvorbisfile) will just read the strings then
carry on to the next packet.  For it to be useful you need:
* encoders to be able to include padding
* taggers able to understand when to write in place and when to
   re-write
That maps to oggenc and the vorbiscomment tool/vcedit.c in the
reference library.

By sheer coincidence[1] the Speex comment header is identical to
the Vorbis one and the Theora comment header is very similar (as
in: the documentation suggests there is a difference but I haven't
checked exactly what it is yet).

[1] No, I suppose not.
-- 
imalone