Vorbis dev - Apr 2002 - Re-encoding digital broadcast to Ogg?

I think everyone here will appreciated that re-encoding an already encoded/
decoded audio track is a bad idea and can create pretty bad artefacts in 
recording.
 
Whilst watching 'Later with Jools Holland' last Friday, India Arie gave
a
very good performance which I thought I would have been good to keep, I then 
realised that since I was watching via digital TV that this audio will have 
been encoded and decoded already.
 
As the decoder (set top box) is self contained I have no access to the encoded
data, best I could do is pick up the PCM to the DAC at which point it is
too late. I guess for un-encrypted channels you could also pick up the 
transport stream from the tuner, but that's getting far too involved.
 
As the world progresses into digital broadcast, does this mean that we'll 
be lumbered with whatever the original compression method is?
 
Does this mean that some form of rudimentary copy protection can be implemented
by encoding in a peculiar way so that if the audio is re-encoded it will
result in a bad quality recording?

Simon Wood 

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...
> As the world progresses into digital broadcast, does this mean that
we'll
> be lumbered with whatever the original compression method is?
>
most likely, yes.  However, note that _most_ digital transmission
standards (at least for audio) are higher datarate than Vorbis, and
presumably have near lossless quality.  I don't think re-encoding AC3 at
say 384 kbits/stereo, encoded professionally from a digital source, should
be as bad as say starting with a 128-kbit MP3 encoding done off the analog
output of someone's discman to their soundblaster.

In the worst case, I would think upping the datarate considerably would
resolve most problems.  If you're recording for your own use, local
storage allocated to audio is probably not your biggest budget item.
> Does this mean that some form of rudimentary copy protection can be
implemented
> by encoding in a peculiar way so that if the audio is re-encoded it will
> result in a bad quality recording?
Studios & various tech. companies are working on this.  see for instance:

http://www.newsfactor.com/perl/story/12166.html

Recently I saw an example of a similar technology built into a set-top
box.  Unfortunately, the artifact was already clearly visible on a
television monitor.  I assume the intent was for an artifact to appear on
copies only.

 >
> Simon Wood
>
 ___  Dan Miller
(++,) CTO and founder, On2 Technologies

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