I just read some of the discussion on the list about 'bitrate peeling' and remembered an interview of Monty that I have read recently. In it he says that Vorbis uses MCDTs <sp> and that these are theoretically reversable. And now, I learn that theoretically we can use bitrate peeling to make smaller files from larger ones, and that leads to my question. Could I theoretically compress my CDs to Vorbis at a rate that is lossless, and then be able to peel those files to 128k/s or lower for a portable device? This would alow me to have archive quality music at home, and lower quality on the go, without recompressing, or storing two versions of each song, one protable and one archive quality. Jason PS - Thanks for Vorbis, its great! --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Wed, Mar 21, 2001 at 11:53:49AM -0700, heard wrote:> Could I > theoretically compress my CDs to Vorbis at a rate that is lossless, and > then be able to peel those files to 128k/s or lower for a portable device? > This would alow me to have archive quality music at home, and lower > quality on the go, without recompressing, or storing two versions of each > song, one protable and one archive quality.Yes, that's a possible application of the idea... Monty --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
>-----Original Message----- >From: Larry Fenske [mailto:lfenske@yahoo.com] >Sent: Thursday, March 22, 2001 13:19 >To: vorbis@xiph.org >Subject: Re: [vorbis] bitrtate peeling and lossless compression ><lossless discussion .snipped> > >Now I've heard both that lossless is possible and that it's not. It wouldbe>wonderful if it were possible. I could peel back depending on the device I >want to play on, and still be able to re-create the original in a year orten>to re-encode with the (by then) new and improved vorbis. Now, I'm savingboth>the original wave file and the ogg or mp3 file. I've hesitated re-encodingall>my waves into ogg because it's still undergoing rapid improvement. If Icould>encode into ogg, throw away the wave (even if some oggs are slightlylarger),>then re-encode later I would be ecstatic (as far as digital audio goesanyway).> >Larry FenskeIf you want truly lossless compression then look at (in alphabetical order) LPAC - http://www-ft.ee.tu-berlin.de/~liebchen/lpac.html, Monkey Audio - http://www.monkeysaudio.com/index.html, RK Audio - http://rksoft.virtualave.net/rkau.html or Squish - we all know where to find this one. These will allow you to get the EXACT input file at a later time. AFAIK, there is no method of 'peeling' any of these. Myles Buckley --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
So, neither Vorbis nor Squish can encode losslessly and peel the bit-rate back to lossy encoding. Would it be practical to make an encoding scheme that would be capable of this? --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.