[vorbis] Bit Rate Peeling Quality

[Colin D Bennett]

Daniel Schregenberger wrote:

>Colin D Bennett wrote:
>
>  
>
>>Graham Mitchell wrote:
>>
>>    
>>
>>>>So, for:
>>>>
>>>>	a.wav --> b.ogg (at q6) --> c.ogg (at q2)
>>>>	a.wav --------------------> d.ogg (at q2)
>>>>
>>>>how are c.ogg and d.ogg likely to compare in terms of audio quality?
>>>>	
>>>>
>>>>        
>>>>
>>>Assuming the files were encoded with current encoders, c.ogg would probably
>>>      
>>>
>be 
>  
>
>>>noticeably less good than d.ogg, but I think better than if you'd done:
>>>
>>>	a.wav --> b.ogg (at q6) --> b.wav --> c'.ogg (at q2)
>>> 
>>>
>>>      
>>>
>>Huh? This is the same thing. You must decode b.ogg to encode c.ogg. 
>>There is no way, as far as I know, to go from ogg->ogg without 
>>converting to uncompressed PCM audio in between.
>>    
>>
>
>There is a way. It's called peeling. The only issue is: there are currently
>only a few "design studies" and no "real" programs to implement this. Just read
>the rest of this thread.
>
>-- Daniel
>  
>

Oh, sorry! I didn't realize that he meant _peeling_ from b.ogg -> c.ogg. 
Jumping back and forth between threads, I forgot where I was. ;-)

Interesting though, I had always assumed that in peeling the peeled 
(lower bitrate) file would be identical in quality to a file encoded 
directly from the source at that bitrate. (This being the primary reason 
I would be interested in peeling.) Is this technically possible?

-cdb

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