[Vorbis] splitting vorbis files

[Aaron Colwell]

I have no idea what stations you are trying to record, but if they are like
the Virgin Radio streams you can just look for chain boundries in the stream.
They change the Title,Author, Copyright info for each song, which forces them
to emit the header,comment, and codebook packets before each song change. I'm
pretty sure these headers are emitted for commercials as well. It should be
relatively trivial to split these sorts of streams apart. If the station you
are interested in does commercial and music switching before the encoder and
doesn't update the TAC info then you'll probably have to resort to some sort
of DSP solution.

Aaron

On Mon, Mar 27, 2006 at 11:42:04AM -0600, James M. Rotenberry wrote:
> 
> Luis Cordova
> 
> Thank you for your message.
> 
> > Please let me know more specifics on your application.
> 
> There are radio stations that stream audio over the Internet 24 hours
> a day in Ogg Vorbis at a constant bit rate, and it is possible to
> capture these files. I would like to remove the commercials.
> 
> It would be possible to edit the files using audacity or some other
> interactive application, but this would be very time consuming.
> 
> My idea is to find the correct 'silent gap' parameters to split
> the file into music and talk pieces. I am guessing that even a
> crude (automated) spectral analysis should be able to separate the
> music files from the talking files, and the talking files can be
> discarded. If a few music files are discarded as well, there is
> plenty more music where they came from!
> 
> To keep the audio as clean as possible, the file should be sliced
> as ogg vorbis and not converted to a new format and then converted
> back to ogg vorbis (like audacity).
> 
> If the process can be completely automated, you can capture at
> night and listen during the day.
> 
> Regards,
>  JM Rotenberry
>  rotenber at io.com
> 
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