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Topic: Could lossless codecs use VBR? (Read 8338 times) previous topic - next topic
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Could lossless codecs use VBR?

I guess this doesnt really fall into a catagory or purpose except it just came to me while i was going through my flac collection.

Is it possible for a lossless codec to encode in VBR? I know that the bitrate used by the lossless codec is what it needs to create a mathmatically recreation of the original file, but wouldnt the filesize be optimized if the bitrate could be varried to fit the music. Like how an mp3 if there is silence the bitrate would go to 4 or 12 then on complex portions rise to 200+. Couldnt the same philosphy work with lossless?

Could lossless codecs use VBR?

Reply #1 –
Lossless is always VBR so yes .

Could lossless codecs use VBR?

Reply #2 –
Quote from: Jan S. on
Lossless is always VBR so yes .


Its VBR? oh i was under the assumption that it wasnt seeing that in fb2k the bitrate didnt fluncuate while the song was playing.

thanks my mistakes.

Could lossless codecs use VBR?

Reply #3 –
foobar2000 shows the average bitrate (though you can make it show the realtime bitrate for MP3/AAC/MPC/Vorbis)

Could lossless codecs use VBR?

Reply #4 –
In fact lossless compression with CBR isn't possible at all because compression cannot be guaranteed for every source material.

Could lossless codecs use VBR?

Reply #5 –
Quote from: breez on
In fact lossless compression with CBR isn't possible at all because compression cannot be guaranteed for every source material.

or, the other way round, when lossless compressors used CBR, it would have to be the same bitrate as the source material to ensure lossless audio, denying the compression (and probably even generating some overhead?).
It's only audiophile if it's inconvenient.

Could lossless codecs use VBR?

Reply #6 –
Quote
or, the other way round, when lossless compressors used CBR, it would have to be the same bitrate as the source material to ensure lossless audio, denying the compression (and probably even generating some overhead?).


Well, according to this page, MLP (Meridian Lossless Packing) claims to have a peak bitrate lower than 9.8 mbps for DVD audio (see pages 1-2 of the document), while uncompressed source material is approx. 13.8 mbps.

Regards,
Irakli

Could lossless codecs use VBR?

Reply #7 –
Quote from: Irakli on
Well, according to this page, MLP (Meridian Lossless Packing) claims to have a peak bitrate lower than 9.8 mbps for DVD audio (see pages 1-2 of the document), while uncompressed source material is approx. 13.8 mbps.


It won't be able to guarantee that for every source file. In page 1-2 they are talking about VBR, not CBR, anyway. So that paper just reinforces what has already been said in this thread.

Could lossless codecs use VBR?

Reply #8 –
Quote
It won't be able to guarantee that for every source file. In page 1-2 they are talking about VBR, not CBR, anyway. So that paper just reinforces what has already been said in this thread.


Agree completely that it is not possible to guarantee compression for all kind of files. I suppose the observation that bitrate always stays below DVD's max bitrate (9.8mbps) was just based on empirical data over large number of samples.

Regards,
Irakli

Could lossless codecs use VBR?

Reply #9 –
Heh, so the MLP encoder would reject a noisy stream that gets past 9.8 MBit/s peak, saying it is too complex to be put on an Audio DVD? So you reduce the resolution of one channel (if the encoder has anything remotely like wasted_bits), and try compressing again, then you mute a channel and try again, etc.

Could lossless codecs use VBR?

Reply #10 –
Quote from: j7n on
Heh, so the MLP encoder would reject a noisy stream that gets past 9.8 MBit/s peak, saying it is too complex to be put on an Audio DVD? So you reduce the resolution of one channel (if the encoder has anything remotely like wasted_bits), and try compressing again, then you mute a channel and try again, etc.


I just hope MLP manages to do all its 'tricks' losslessly... 

Could lossless codecs use VBR?

Reply #11 –
Maybe it just has a really really big bit reservoir?
 

Could lossless codecs use VBR?

Reply #12 –
The SurCode MLP manual has a good description of the process. Basically, if a passage exceeds the maximum acceptable bitrate then the track must be re-encoded with either some lowpass filtering done to reduce the bitrate, or one or more channels must be encoded with some number of LSBs cleared (like what lossyWAV does).

BTW, I don't know if I've seen this news on HA yet, but MLP was reverse engineered and a decoder is being put into FFmpeg (not sure if it's in SVN yet).