Vorbis - Mar 2007 - Splitting a WAV file to aid gapless playback

Assuming I have a WAV file that represents a continous performance, e.g. a
recording of a live concert, which I want to play continously on a CD but
nevertheless have track marks so that individual items can be selected some
WAV splitting programs offer the ability to split the file into pieces which
are an exact multiple of the CD sector size so that when recording all these
files to CD with no sector gap there is no extra silence introduced.

Is it possible to do the same with Ogg/Vorbis files, i.e. is there a
block/window size where I can make each WAV file to be encoded consist of
a whole number of these blocks?  So what is it please?

TiA,
Steve.

On 3/19/07, Steve Fosdick <xiph@pelvoux.nildram.co.uk>
wrote:
> Assuming I have a WAV file that represents a continous performance, e.g. a
> recording of a live concert, which I want to play continously on a CD but
> nevertheless have track marks so that individual items can be selected some
> WAV splitting programs offer the ability to split the file into pieces
which
> are an exact multiple of the CD sector size so that when recording all
these
> files to CD with no sector gap there is no extra silence introduced.
>
> Is it possible to do the same with Ogg/Vorbis files, i.e. is there a
> block/window size where I can make each WAV file to be encoded consist of
> a whole number of these blocks?  So what is it please?
Fortunately, with vorbis you don't need to do that.

The format handles the start and end of the stream slightly specially,
and will ensure that only precisely the correct number of samples are
output.

Mike

Directly appending one Vorbis stream to another creates a single gapless 
stream.

If you use a Unix-like operating system (like Linux) you can type
cat vorbis1.ogg vorbis2.ogg > vorbis1and2.ogg

Going in the other direction, however, is not really as practical. 
Vorbis is broken into chunks to fit into the Ogg encapsulation. These 
chunks (called Pages, I believe) are fairly arbitrary and not based on a 
number of seconds, for example.

If you need completely gapless playback, you should be able to use an 
application like Nero to create completely seamless audio on a CD. I 
haven't had trouble that way. (Then again, it's been a couple years 
since I last burned an audio CD...)

-Chris

Steve Fosdick wrote:
> Assuming I have a WAV file that represents a continous performance, e.g. a
> recording of a live concert, which I want to play continously on a CD but
> nevertheless have track marks so that individual items can be selected some
> WAV splitting programs offer the ability to split the file into pieces
which
> are an exact multiple of the CD sector size so that when recording all
these
> files to CD with no sector gap there is no extra silence introduced.
> 
> Is it possible to do the same with Ogg/Vorbis files, i.e. is there a
> block/window size where I can make each WAV file to be encoded consist of
> a whole number of these blocks?  So what is it please?
> 
> TiA,
> Steve.
> _______________________________________________
> Vorbis mailing list
> Vorbis@xiph.org
> http://lists.xiph.org/mailman/listinfo/vorbis
>

Steve Fosdick wrote:
> Is it possible to do the same with Ogg/Vorbis files, i.e. is there a
> block/window size where I can make each WAV file to be encoded consist of
> a whole number of these blocks?  So what is it please?
You could concatenate the Ogg Vorbis files (using the method described 
elsewhere in this thread), decode the big Ogg Vorbis file to a WAV file, 
then use wavbreaker (http://huli.org/wavbreaker/) to break apart the WAV 
file on boundaries that will replay seamlessly when burned to audio CDs.

Since you're not re-encoding this WAV file you shouldn't lose any
quality.

Audacity (http://audacity.sourceforge.net/) is worth experimenting with 
if you set its selection size to be CDDA frames.  I'm using v1.3.2beta 
on my GNU/Linux system and it works quite well.  I haven't tried working 
with it in CDDA selection mode (for lack of a better term), so I can't 
say for certain that you'll get what you want out of it.  Audacity will 
read Ogg Vorbis files but I'm not sure if it will read your concatenated 
Ogg Vorbis file in its entirety.