

Bitrate Peeling with Ogg Vorbis 404
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."
Handy for porting your music to a portable player (Score:4, Insightful)
And one more small improvement on that... (Score:4, Insightful)
Re:And one more small improvement on that... (Score:2)
Until, that is, you take a look at du -h
Let's hear it for Pixie Dust! Come on Toshiba, I want a 40G 1.8" drive from you guys by year's end.
MISQUOTE! (Score:2)
How does my quip "iPod'ers with 20 gig drives wouldn't lose sleep over it" become quoted as "20G should be enough for anyone!" in your post?
You must work for CNN.
Handy? Nah, Perfect! (Score:5, Insightful)
I can't wait til this one hits.
Re:Handy? Nah, Perfect! (Score:2, Interesting)
Re:Killer App? (Score:2)
Re:Killer App? (Score:2, Interesting)
Re:Handy? Nah, Perfect! (Score:4, Informative)
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:Handy for porting your music to a portable play (Score:2)
Speaking of such, are there any Ogg-supporting portable players, or players in development?
(Granted the Hardware Support page [xiph.org] at Xiph has some info, but I'm curious if there's anything else known)
audiophile /.er's? (Score:2, Insightful)
Re:audiophile /.er's? (Score:5, Insightful)
audio enthusiasts listen to music.
audiophiles listen to equipment.
Me, I'll take the music.
Interesting (Score:2)
It would be even cooler if they could disperse the signal in time (i.e. across several packets) and just drop every n'th packet in order to create a lower bitrate stream without making it sound choppy.
Re:Interesting (Score:2)
First off, remember that Vorbis is a perceptual encoding scheme like MP3. What it does is breaks the sound at a given time into a number of components. The 'less important' components are filtered out, and the remaning ones are written to your file.
For bitrate peeling to work, the sound data, when it's written, needs to be organized in such a way that it's trivial to look at the sound components and again figure out which ones can be thrown away to achieve the desired bitrate.
Idealy, throwing away the least significant n frequency bands would give better results than just dropping every n'th packet.
good idea, but... (Score:4, Informative)
Let me know when they've got something working THEN I'll be impressed
Re:good idea, but... (Score:2)
They (as in the ogg vorbis dev community) are saying it would be pretty cool for sampler tracks if you could save the 'peeled' bits. You could offer the low bitrate version for free. If people like it, they can pay extra for the peeled bits and then use some tool to re-integrate the free and peeled bits to get the full quality file.
Re:good idea, but... (Score:2)
But for streaming and portable players, it's sure great.
Re:good idea, but... (Score:2)
Because whoever owns the server doesn't have to create and maintain multiple copies of the original file encoded at different bitrates. That would save them on hard drive space and file management too.
Re:good idea, but... (Score:2)
http://www.xiph.org/archives/vorbis/200005/0023
portables (Score:2, Interesting)
personally, i'm converting over from 256kbps mp3 to 128kbps vbr ogg and i'm saving TONS of space and not really sacrificing any quality... does anyone know of a petition or something similar to get mainstream hardware manufacturers to include ogg support in their hardware?
Re:portables (Score:2)
That's great (Score:2)
It's commonly observed that oggs of lower bitrate compare to mp3 at higher bitrates.
i understand that... (Score:2)
Re:portables (Score:2, Informative)
Re:portables (Score:2)
It's not a petition, per se, but the Hardware Support page [xiph.org] at Xiph.org lists the contact info (including e-mail addresses) for companies considering Ogg support for their portable players.
It couldn't hurt to write to them; I did.
Might be cool as an audio effect (Score:2)
Audiophile? (Score:2, Interesting)
Cool idea though.
Audiophiles? (Score:4, Informative)
Lately I've been finding all I can download off P2P programs like Direct Connect [neo-modus.com] and Furthurnet [furthurnet.com]. 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? (Score:2)
Re:Audiophiles? (Score:5, Interesting)
No one has been able to until then, and I'm not only talking (only) about average people. I have some friends which (unlike me) have a decent equipment.
Usually these guys were able to clearly distinguish 160kbps from the set. With 2-3 pass they detected the 192kbps track and they couldn't tell the difference between the 256kbps and the original.
Maybe I could send you guys some samples...
Just keep in mind also that MP3 is the same type of compression than DTS & AC3 (Dolby Digital) and I've never heard someone complain about those (especially DTS). If you're unhappy with quality, just increase bitrate. And if those guys in the MPEG consortium felt that 320kbps should be the maximum, It should mean something.
Lossless compressors have such a poor ratio!
Re:Audiophiles? (Score:2, Interesting)
You can argue that 256 is the same.. and for your purposes, it probalby is. For most common equipment, it surely is.
Someone with a really well educated ear and really good equipment can probably hear the difference though. Because there IS a difference.
Another thing... with high bitrate mp3.. when comparing between an original and the compressed version in a blind test, someone will be able to tell you they are different, but not which one is the original... becasue both sound good.
Re:Audiophiles? (Score:3, Insightful)
Well duh, then what's the problem? If they both sound good then you'll enjoy either one, so listen to the one that uses less bandwidth.
*sigh*
Re:Audiophiles? (Score:2, Insightful)
Many "Audiophiles" enjoy listening to how accurately they percieve their setup to be reproducing the original sounds... that's why they don't like lossy compression. It's not because it doesn't sound good.. it's because they are chasing accuracy. This accuracy becomes as important to them as whether or not they like the tune in the first place.
Re:Audiophiles? (Score:3, Insightful)
Actually, they are chasing precision.
None of them have a FUCKING CLUE as to how accurate their system is, or isn't.
Re:Audiophiles? (Score:3, Informative)
Secondly, I understand that it is hard (and sometimes impossible) to hear the differences between a properly-encoded MP3 and the original, but that does not mean it will be true for all cases. Music varies greatly, and while you may not be able to hear a difference on certain songs, there may be others where it is quite apparent. I don't think anyone can debate (anymore) that a properly-encoded MP3 using --alt-preset standard with LAME is easy to pick out. Most of the time, to most people, it will be transparent. However, arguing that people should use MP3 over lossless is a whole different ballgame.
One nice thing about lossless is that you always have the choice of converting it back to the original WAV and using that as source data for further processing. Once you've converted something to MP3 (or any lossy format) you can't go back. There are applications for lossy and applications for lossless, but I think comparing the filesizes and claiming MP3 is the way to go isn't really appropriate. Just IMHO, of course. I am speaking from the point of view that your intent is to archive your audio or something similar.
Re:Audiophiles? (Score:2, Insightful)
I'm using MP3 to backup my CDs. I've broken a couple of CDs recently (partly because of my 1 year old son
To try and answer everybody, you actually made a point I failed to address. MP3 should be used for LISTENING. The whole point of this compression is to remove frequencies that the global level of music is masking. Therefore, if you take an MP3 and apply a filter out of it (any kind), you will loose A LOT OF QUALITY, because the point of any filter is to modify the original and so some frequencies that were masked could have become audible.
Besides that, the main problem with MP3 is not a masking of frequencies but artifacts (I said the MAIN problem, of course frequency loss counts). The psy model used in an mp3 encoder will allow strong artifacts that could (and will) show up if you apply basic filters.
Re:Audiophiles? (Score:3, Informative)
Yes I've heard Dolby Digital compression is similar to MP3 compression. However, DTS uses very little compression, which is why it sounds better and takes up more space on your DVD disc. Check out the DTS FAQ [dtsonline.com].
Re:Audiophiles? (Score:3, Informative)
I use FLAC to compress my music, which is free and lossless. It outperforms shorten on average (smaller compressed files), and is also supported by some hardware playback devices (Rio, Phatbox, some Kenwood stuff) unlike Shorten.
I play back through a Hoontech card with digital output and use an offboard MSB Link DAC III (the computer is acoustically isolated from the listening room) which feeds into a Creek 5350 integrated amp driving Vandersteen 2ce Signature loudspeakers.
I also use lossy compression for my car mp3 player--the stereo there isn't audiophile quality anyway.
Sumner
Re:Audiophiles? (Score:3, Informative)
And we should care about this, why?
Re:Audiophiles? (Score:2)
I'm not an audiophile myself but find their utterances interesting.
Yes, yes, yes... (Score:2)
The true measure of an audiophile.
Re:Audiophiles? (Score:2)
Audiophile = someone who loves audio. The guys who sell $14,000 record players have extended the meaning of audiophile to "someone who loves audio and is willing to spend five or six figures on the fanciest looking equipment."
So by the dictionary definition, yes, there are many thousands of "audiophiles" who enjoy MP3. Get over it, for chrissake.
Its mostly live shows, and they are all in
Having said that, there is actually a good reason why lossy codecs are especially bad at encoding live shows. Lossy codecs do their magic by removing info that is "masked". Eg if two sounds are close in frequency but one is significantly louder, the human ear/brain will only hear the louder one. MP3 does best with sounds that a) can be broken down into a smallish number of frequency components and b) contains a lot of elements that the human ear can't perceive.
The problem with live music is that is is exactly the opposite of a studio recording in those respects. It cotains a lot of "noise" (eg applause), which has a broad spectrum, plus a lot of quiet stuff like background murmurs, which we *can* hear. It's just much more complex.
You just need to use a higher bitrate for live than you do for studio recordings, and everything will be fine. Unless you've done a double-blind A/B test and can tell the difference between a good CD and a good MP3, I'm really not interested in your opinion on what "audipohiles" should be listening to.
Many "audiophiles" are idiots (Score:2)
He was bragging about his expensive (and therefore wonderful) setup, when he mentioned having "super-high quality" digital cables, which cost him $2,000. I asked him how much "low quality" digital cables cost, the answer? About $15!
I asked him what the difference between the two was, he claimed that the high-quality digital cables gave the music more "body"!
It may have been cruel of me, but I just couldn't help but explain what digital actually meant.
The moral of the story? That much of the audiophile community are simply the blind leading the blind, pseudo-techie alchemists, who assume that expensive means better.
Re:Many "audiophiles" are idiots (Score:2)
me, I bought the $15 cable.
(Somebody somewhere is going to have to spend a week with me and explain why you have to worry about jitter in any piece of equipment *EXCEPT* the last one.
And even then I have my doubts, but atleast it is possible to measure jitter.
Re:Audiophiles? (Score:5, Informative)
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 [sourceforge.net] 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:Audiophiles? (Score:3, Interesting)
By the way, you might want to check out the MAD Winamp plugin at http://www.mars.org/home/rob/proj/mpeg/mad-plugin
Re:Audiophiles? (Score:3, Funny)
Er, why do I need to do that, when you say things like this:
Of course a sound card is useless for listening to music.
This may come as a shock to you, but the vast majority of people who listen to music on their computers would consider that a ridiculous statement. No extrapolation is necessary on my part - that's a direct quote.
Note the word listening.
Wow, I'm so confused as to why I've been playing mp3s on my PC up to now...I thought I was listening to music. Guess not.
Nice troll yourself :)
Tim
Re:Audiophiles? (Score:2)
I can understand ones love for quality music reproduction. Some people take it to the extreme but to each his own. I define an audiophile as someone that lost entertainment value of the music and became overly concerned or even obsessive with nothing but the quality. An example is your statement above. Basically an audiophile is not happy with anything but the perfect listening environment using his own home made speaker interconnects, directional wires, and triple filtered power supplies. How can you enjoy music the other 98% of your day, like when on the subway, in your car, at a night club etc.. I truely enjoy a good relaxing listening environment (at least on a moderate budget) but I also can hear any track from Dark Side of the Moon on AM radio and still get enjoyment from it.
Re:Audiophiles? (Score:3)
That's all well and good that you know what you want. Me, I want a format that can be downloaded in at least realtime (1 second of music in 1 second of download time) on a normal, lightly used network connection, and which takes up only reasonable amounts of space on disk.
But hey, what do I know, I just do professional network consulting and system administration to pay my way through school. =D
Easy workaround. (Score:2)
Re:Easy workaround. (Score:2)
An audio wanker who thinks anything by Bose is high-end and circles his CDs with green magic marker to make the laser track better might pay $100 a foot for such cable, but an audiophile is interested in things that sound better and not things that empty his pocket.
Uncompressed audio does sound better than 128 kbit mp3 on good gear. I use mp3 in my car, but uncompressed audio on my home system.
Sumner
Re:Easy workaround. (Score:2)
-nod- At some point, you have to yield to the law of diminishing returns, just like anything else. In all honesty, I can hear the difference between 160k mp3 and CD if I'm using my nice Grado headphones, but it doesn't bother me. Over that bitrate or using ogg I can't even hear it myself, but I've got untrained ears. (Thank goodness)
Then again, I won't use anything but a genuine Tulip 21143 network card, so I guess everybody has to have their one thing to be irrational about
Re:Easy workaround. (Score:2)
No you won't. Plenty of double-blind listening tests have shown that, and plenty of premier recording studios use cable that's an order of magnitude or two cheaper than that with excellent results. I'm talking Telarc-level recordings here, too.
Sumner
Re:Audiophiles? (Score:3, Funny)
True story:
Jerry Lewis sits at an editing console, editing his latest film. Unfortunately he is not happy with the way it is going. Stanley Kubrick stops in, asks is he can watch. Jerry says sure.
Jerry Lewis (coining the phrase): You can't polish a turd.
Stanley Kubrick (without missing a beat): You can if you freeze it.
-renard
Re:Audiophiles? (Score:2)
Stripping data, eh? (Score:5, Funny)
Alternative use.. (Score:5, Interesting)
Or, Slightly modified, You could share all your high quality oggs on a P2P network, and have your client peel it down to 'future-legal-to-share' low quality files.
Re:Alternative use.. (Score:2, Interesting)
Re:Alternative use.. (Score:5, Insightful)
Or, even more interesting: peel a Vorbis file all the way down to the minimum quality. Concatenate the bits together in order. Now you have a file that you can play back, in its entirety, when it's only 10% downloaded. All you have to do is wait for the minimum quality version to download; from then on, the entire file is playable. It's just that the longer you wait, the more peels get added, the higher the quality... holographic audio downloading.
Re:Alternative use.. (Score:5, Informative)
Holographic? No. Progressive (similar to progressive JPEG)? Yes.
Why stop there? (Score:3, Interesting)
The Second Time Around (Score:2, Interesting)
Is this really such a useful idea? (Score:3, Insightful)
Sounds more like it would be unique to OV, if they implemented it.
The point is, nobody does it now. Perhaps this is because there's really no need for it. Consider the list of "very sexy applications:"
Re:Is this really such a useful idea? (Score:2)
Remember back when you could choose to download large files in one chunk or in floppy-sized portions? Often even if you didn't intend to put them on a floppy you'd get the split version if you didn't trust your network connection -- or if you didn't have time to download the whole thing. Today we have rsync -- isn't it a Good Thing (TM)?
For audio being able to download partial files or skrink a file isn't a big deal because the files rarely get huge (if it's long, it's probably voice and therefore can be compressed to hell), but for video this is a big deal. I won't go into the applications, just read a bunch of the other posts and 1,$s/audio/video/g* but notice how much more sense they make when you're talking about things that barely fit onto a single DVD now. For example: imagine watching streaming video that, once it's downloaded at a minimum acceptable quality, starts to improve while you're still in the middle of watching it (or even while it's sitting on your HD and your computer doesn't have anything better to do).
Asides from any practical benefits, bitrate peeling introduces the concept of a file storing multiple, modular representations -- which is certainly as profound as moving metadata inside of files.
* That's replace all copies of "audio" with "video" for the vi-impared.
Re:Is this really such a useful idea? (Score:2)
You will get plenty of reartifacting during reencoding since you are going to such a low quality. It is MORE important to have as much information available as possible when encoding to a low bitrate, not less.
Your question "Wouldn't you just buy a higher-cap memory card?" is incredibly arrogant and dismisses inexpensive but nonexpandable devices of the future which will support ogg and cost nearly nothing. Before long we'll be getting shit like earrings with a bluetooth interface that play oggs for free in our cereal boxes, and they won't have upgradable memory. That's not the real issue though, which is that right now memory cards cost money and some people store up their money and buy a player and can't afford more than the 32mb the base model comes with. (That's not me, I'd rather use CDs at that point, but you catch my drift.)
Re:Is this really such a useful idea? - absolutely (Score:2, Insightful)
A spurious example (Score:3, Interesting)
Also, you assume the sweet spots are 2x the one before. In fact, jumps of more like 1.25 are likely to be optimal (albeit with a lot fewer jumps!).
Multicast (Score:2)
It would be great for multicast-type situations (including, but not limited to IP multicast.) You could send one high-quality signal out from a central point and then shave off bits to fit the stream down to the quality needed by the end-user.
For instance, users on a 56k modem could listen to the same multicast stream as a broadband user (ie, no need to send out multiple, separate versions from the source)-- this assumes the presence of routers (or conversion boxes) capable of doing the peeling as needed.
All in all, very useful.
Some basic Math... (Score:2, Informative)
Original High Quality file: 10mb
3/4 Quality file: 7.5mb
Half quality file: 5mb
Quarter quality file: 2.5mb
Total for all variations without peeling: 25mb
Or, store the High Quality 10mb original only and dynamically peel. Savings, 15mb (1.5 times more files)
No need te reencode a new file for each device (and some of us have many!)
Just FYI
Yes, it is a very good idea. (Score:5, Insightful)
1. Keeping hundreds, or even ten separate files as described, each half the size of the previous, is not plausible. I'd assume the author was a troll, but since no one else has mentioned it, perhaps the obvious fallacy with that idea is slipping past even the sharper readers. A 10MB file can be split in half at most 23 times before it is only 1 byte long, far fewer before the quality level is unacceptable. Secondly, the idea described in the article, provides for dynamic bitrates, not simply half the original bitrate. To provide even similar functionality, one would need files in ranges from 1MB to 10MB in relatively small increments, totaling well in excess the "twice the size of the largest file" as suggested. Even so, this would be deficient in that the bandwidth could not be throttled mid-stream.
2. Second, decoding and re-encoding the same file with a different bit rate will almost certainly result in poorer quality than the technique described. The safer, more straightforward solution, is to perform reduction operations on the transformed data, rather than the decompressed waveform. Otherwise, amplified artifacts from the original compression will be present in the new file.
3. Third, the strength of the poster's argument lies entirely in the choice of ratios. Downloading a 5MB file rather than a 10MB file leaves only 5MB remaining. To paraphrase, are you really going to opt to download the 10MB complete version when your software can download the remaining 5MB in half the time?
There are a number of problems which bitrate peeling address, not the least of which are 1) reduction of storage space as described previously, 2) dynamic bandwidth regulation of audio streams for streaming radio, future cellular phones, VOIP, and network appliances running on congested networks, 3) file size reduction without transcoding, 4) user-specified bandwidth on demand, 5) automatic preview generation from source without any extra administrative overhead.
I'll even add my own... the ability to download a very high quality file and start listening to it immediately at lower quality without interruption. By the time the file has played through, the download may be only 50% complete. If I decide not to continue with the download, I have wasted no more time than that necessary to listen to the file. If I want the file, I have only 50% remaining.
In some ways, this is similar to the rationale behind interleaved images, except that it is unlikely that you will need to listen to the same file repeatedly at progressively higher bitrates. Nothing prevents this of course.
-Hope
Re:Is this really such a useful idea? (Score:2)
This appears to be a fairly natural thing for compression based on wavelet transforms, which were used by both SPIHT and VDO.
Re:Is this really such a useful idea? (Score:2)
No, you're right, the overhead would instead be up-front, having to encode at multiple bitrates, and more overhead in storage costs. It's a tradeoff.
Suppose the full file is 10 meg, and you download a 1 meg sample. Are you really going to opt to download the 9 meg "patch" file, rather than the 10 meg complete version?
Why are you assuming the worst-case scenario? What if I downloaded a 5MB version, and now I only need the other 5MB? Multiple that times 10 tracks, and that's only 50 more MB I need to download, instead of another 100MB. Now assume the client you're using to handle these purchases is smart and does this all in the background. Yes, it's a great benefit!
You're Right (Score:2, Interesting)
Why would you need a 21k CD player, you ask? If a CD player is playing back an exact digital file, than shouldn't all CD player's sound the same? The answer is simple: let your ears be the judge.
I was initially skeptical when I was first shopping for stereo equipment, but there is a world of difference between a consumer CD player obtained at the chains like Best Buy, Fry's, etc. and an audiophile CD player. The difference is primarily in the level of clarity or resolution that you can hear from a quality CD player. The difference is subtle yet dramatic, you can hear instruments and detail that you simply could not make out before.
To make a long story short, the quality of mp3s is typically even below that of a CD played on a cheap consumer CD player. No "audiophile" will listen to them as a primary audio source. That said, I have an mp3 player that I use when running and I have mp3's on my computer. Everything has its place, but the place of mp3's or ogg is not in audiophile stereo systems but in the world of music sharing where file size is a critical issue.
Re:You're Right (Score:2, Interesting)
Many non-audiphiles like to listen to music because they like the tunes and lyrics, not because they want to super-analyze every insturment. In this respect, mp3 & ogg & whatnot are fantastic. If they suck, why are they so popular?
So.. you tried this CD player in the same audio setup you were used to using, to compare it side by side with another player you were used to with no other factors that change?
yes.. there are differences in CD players... mostly due to oversampling & better filters, and good quality output components. That, and good power supply circuits.
The difference between a cheap cd player and a $1000 cd player will be noticeable; the difference between a $1000 player and a Linn Sondek is more debatable.
Audiophiles? (Score:5, Funny)
Re:Audiophiles? (Score:2)
An yo pint is wha?
Re:Audiophiles? (Score:3, Funny)
Re:Audiophiles? (Score:2, Funny)
Musi withou hig frequenc is lik wods mising leters.
Muslims without thigh frequency fish link wonders skirmishing accelerometers?
I don't get it. How did this get modded up?
This reminds me... (Score:5, Funny)
"Those who sacrafice sound quality for hard disk space deserve neither."
Cool idea to throw around though.
Peeling! (Score:5, Interesting)
One thing that hasn't been discussed here is that a lot of people feel that Vorbis is transparent at something like quality setting 4. Other people think it's transparent at quality setting 3. Others think it's great at 1. I release my stuff at 4, but bitrate peeling will let people peel those down to what sounds good to them. Maybe they want to monkey with it, and maybe they don't, but the option to do this without re-encoding is sexy.
It's not just a 'chop it down for modem folks' thing, it's also a letting people choose for themselves situation that I think is more important.
Features are cool, but features that give people options apart from 'use it or not' are even cooler.
That's it for me. Please donate [vorbis.com] to Xiph.org, and then go listen [diff-eng.net] to some tunes. Enjoy!
Re:Peeling! (Score:5, Informative)
I really would like to donate, but not through PayPal [paypalwarning.com]. Could you please offer some other method of payment like the Amazon Honour System [amazon.com] or Element5 [element5.com]?
Re:Peeling! (Score:2)
Who says I'm in the USA or can write $US cheques without serious banking fees?
Re:Peeling! (Score:2)
I'm not all that familiar with Ogg so I'll give you the benefit of the doubt here that this is cool. However Ogg has enough working against it in the form of MP3 that adding complexity to it is going hinder it's acceptance, not increase it.
Re:Peeling! (Score:2)
Cool, but not unique (Score:5, Interesting)
MPEG-4's scalable profiles provide a similar effect (albeit in the other direction, with enhancement layers). Some of the higher end audio codecs (beyond CELP and AAC), like ER BSAC (Error Resistant Bit Sliced Arithmetic Coding) do exactly this. The idea in this case is that the server will in real-time only provide as many bits as the connection can currently provide. Very nice for wireless.
QDesign's QDX format does almost exactly what is described for Ogg, with arbitrary bitrate peeling down to the 1 Kbps level. The idea is that you could copy as much data as you want to your mobile player, and it'd dynamically thin to the data rate that would fill up your device.
And still image codecs like JPEG have used progressive modes for years, where additional data adds more detail to the image.
Progressive Ogg? (Score:3, Interesting)
All these anti-peeling posters are retarded! (Score:5, Interesting)
The only option is transcoding, which compounds compression errors (decode, reencode). I often wished the MPEG group would have been more intelligent in the design of their bit-allocater so that you could "thin out" the quantization of the power bands by looking at the "right parts" of the MP3 frame. Alas, this is not possible.
But the Vorbis designers have made this possible, thus making it possible to have high-quality and low-quality versions derived from the same source file without additional processing. I imagine you have certain restricted choices, due to how quantization information is bundled up/packeted. But it isn't just sexy, it would be stupid to NOT DO IT. It takes just a little forethought on how to lay out the information in a hierarchial fashion. What makes anyone think that this is any harder then decoding/reencoding. I guarantee it has a time complexity on the order of a straight copy.
Hell, formats like SHN and FLAC can do it, just substitute short codes for long codes at a certain rate; it'll add a bit of wide-band energy on decode, raising the noise floor in proportion to the space savings you gain.
So anyway, "poop on you" to all these wanna-be audiophiles/slashdot-know-it-alls who don't no a good thing when they see it.
Don't like it, keep sucking on that Layer III.
DTS has similar system (Score:4, Informative)
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.
iPod seems to do this anyway (Score:3, Interesting)
What Is The Technical Problem with MP3 Peeling? (Score:2)
Why can't we peel away detail from an MP3? It's pretty clear we can't, but why?
The *massively* simplified description of how MP3 works is as follows: Grab a chunk of sound, call it a frame. Split the frame into 576 frequency bands, figure out which ones the psychoacoustic system cares about for a given period of time, and reduce detail against whatever's left. This process, quantization, is roughly equivalent to rounding 1.1241 into 1.1. Move ahead half a frame, and do it again.
There's a bunch of other funkiness -- looking at previous frames to figure out what's important in this one, losslessly encoding frame data whenever possible, and of course, the actual algorithm used to allow frequency quantization (the Discrete Cosine Transform) -- but at it's core, MP3's just "chop, split, pick, and trash".
Now, at the end of the day, an encoded MP3 contains unquantized material -- larger MP3's trash less. Why can't I go into the larger MP3, throw out more data, fix up the headers, and shrink the size of the file?
Yours Truly,
Dan Kaminsky
DoxPara Research
http://www.doxpara.com
Been There, Done That (Score:2, Interesting)
adaptive peeling (Score:3, Interesting)
adjust the peel factor on the fly.
Re:Wow (Score:5, Funny)
Though it does sound like a pretty cool way to downsample a stream.
-hero.
Re:Wow (Score:2, Funny)
I call BS. The parent poster is making all that stuff up.
Or am I the one that's bluffing?
Re:not impressed (Score:2, Interesting)
I'm not sure if it's frequencies that are being separated here - the idea seems similar to wavelet image compression, where refinements to the original data arrive over time.
Note I know nothing about Ogg, so it probably isn't based on a wavelet approach, but the idea sounds more like you get low resolution data (covering the full frequency range) followed by higher resolution data. I.e., you're increasing the sampling rate over time - but the range of frequencies you sample is the same regardless.
Re:not impressed (Score:3, Insightful)
I = one bit
----A 128k stream----
IIIIIIIIIIIIIIIIIIIIIII
----A 96k stream-----
IIII IIII IIII IIII IIII
It simply removes some of the bits, not any specific freqency of the high/low/mid.
and it looks to be an impressive streaming method
Re:not impressed (Score:2, Funny)
Bitrate peeling is not a good idea because I say so and need to look important. Transcoding is such a better idea because it introduces no artifacts and takes a much shorter time to do. Not that you should do that because nobody uses a narrowband internet connection anymore, at least nobody that I care about. Comparitively RealAudio is great! No, really! I enjoy giving my personal information to someone just so I can listen to commercials and kill pop-up advertising before it asks me if I want to upgrade, then crashes my computer!
While I conceed it's possible.. nobody else knows what they're talking about! Um... look over there! (exits stage right...)"
Yes. Thanks. Really persuasive argument.
Re:not impressed (Score:2)
But even *I* think 128k MP3s really aren't that great when compared to the original music.
No comment on ogg at 128, never use it.
Re:progressive jpeg, mp3pro (Score:2)
Most lossy compression schemes like JPEG (regular) work off the concept of using a domain transform, only saving what are considered to be the most significant coefficients after said transform. This makes almost every lossy compression scheme out there is a canidate for bitrate peeling of some sort of another. I'm just surprised that on one does it; having not read the JPEG standard though, I agree that it might be technically challenging (or simply not much in demand).
Having studied wavelets, I can state that they definitely could support a technique similar than this. Given a properly ordered stream of discrete-time wavelets, one could chop off the last few cycles and similarly lose just a bit of quality.
Re:STOP USING KEWL (Score:2)
As in the song, "Frigging in the rigging". Somewhat rude.