Bitrate Peeling with Ogg Vorbis

Yort writes "Thought this might be interesting to some audiophile /.ers - there's been some discussion on the Ogg Vorbis lists, summarized in the most recent Ogg Traffic, about "bitrate peeling". In short, it's where you can simply "peel off" the high resolution data from the ends of an audio stream packet to come up with a smaller, lower quality stream. Brings up a number of geek-cool opportunities."

Comments

good idea, but...

[ameoba]

Bitrate peeling is a briliant idea, and would be a major win for Vorbis if they ever actually provide an implementation of it. It's something that the format supposedly supports, but right now it's still just a hypothetical application.

Let me know when they've got something working THEN I'll be impressed

Audiophiles?

[Pinball Wizard]

So who out there is an audiophile and listens to compressed streams of music?

Lately I've been finding all I can download off P2P programs like Direct Connect and Furthurnet. Its mostly live shows, and they are all in .shn format, which is a lossless compression format that restores to the original .wav file.

These communities shun both compressed files like .mp3 and trading anything that has been released commercially. What you do get is great recordings of live music from bands like U2, DMB, Grateful Dead, etc., all ethically traded and in their full audio glory.

The audiophiles I know pretty much don't listen to mp3, ever.

Re:Audiophiles?

[Monkelectric]

I am a certified audiophile... High bit rate mp3 are very difficult to tell from the original... however most mp3s are made by amateurs with bad encoders that are *crap*.

Before encoding my cd collection I spent a month playing with different encoders and settings to find what might satisfy my ears. I eventually settled on lame with the "new vbr method" and the highest quality settings and I've been very happy with the results. If something better comes along, I'll get my CDs out from under my bed and re-encode :) The only time I've been able to tell one of my mp3s from the CD is on albums I am intimately familiar with, i.e. the Steely Dan Box set. I have easily heard it 500 times, and every once in awhile you notice the timbre of a cymbal is just a little bit different then you remembered it.

However, something no one ever thinks about is your mp3 *player* and sound card. An internal sound card is worthless for listening to music (I use a M-Audio Delta1010 which is part of my studio setup). Also the mp3 player makes a *huge* difference. It will probably come as no surprise that Winamp is shit. I like CoolPlayer which is based on libmad -- a 24 bit integer only mp3 decoder. The extra bits are important because they reduce quantization errors during decoding, there is a noticeable difference in clarity between coolplayer and winamp. Also, standalone MP3 players tend to have better mp3 decoding because they (usually) use a DSP to decode the and DSP programmers are well aware of accuracy issues.

My point is, mp3 is tolerable for casual listening even to an audiophile *IF* it's done correctly. The problem of course is that the computer is about the *worst* place to be listening to music because its at such a disadvantage (poor quality signals, noisy electronics, bad DACs, shitty speakers).

However, your need for a higher quality signal is directly proportional to the cost of your stereo. If you have a small portable stereo, the radio is about the best quality you can reproduce anyways. The quality of mp3's is superior to what the average computer can reproduce. But If you have a 30,000$ stereo as some obsessive audiophiles do, its pretty silly to listen to mp3s on it (but you're gobbling up dvd-audio discs as fast as they are made anyways).

Re:Peeling!

[Jucius Maximus]

"Please donate [vorbis.com] to Xiph.org, and then go listen [diff-eng.net] to some tunes. Enjoy!"

I really would like to donate, but not through PayPal. Could you please offer some other method of payment like the Amazon Honour System or Element5?

Re:Handy? Nah, Perfect!

[rseuhs]

this is not an ogg specific killer app... substitue ogg_to_bitrate(); with mp3_to_bitrate(); and your killer app will work for the 'competition'

No, mp3 would have to be reencoded, which would make the quality much worse and would take a lot of time.

When I want to put music into my player, I want it now, I don't want to wait 1-2 hours.

Re:Alternative use..

[Jahf]

Holographic? No. Progressive (similar to progressive JPEG)? Yes.

DTS has similar system

[nedron]

The home theatre version of DTS uses a similar mechanism, allowing DTS to continue to add discreet channels and additional features while remaining compatible with older DTS decoders. Basically, the decoder ignores any information in the stream header that it doesn't understand.

That's how DTS was able to add a discrete surround channel (DTS ES) without causing problems with older receivers. Dolby can't change their header without breaking backward compatibility, which is why their extra surround channel (DD EX) is matrix encoded.