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Your music collection of MP3/OGG/AAC may be re-sold to you in 32-bit (regular CDs use 16-bit, which was always just barely acceptable to critics of the format).

Nonsense. The average person can't resolve past 12 bits. Theoretically, 16 bit recordings can reproduce a 96db range of sound intensities. Do you think you could hear a person whispering across from you at a loud rock concert? Well that there represents about a 90db range of intensity -- well beyond the capabilities of most if not all human beings. Hardly anyone who claims to be able to hear the difference between a 20-bit recording and a 16-bit recording can do so under a properly designed and administered double blind ABX listening test (notice that I didn't say it isn't worth recording at higher bit rates prior to mixing down to 16 bits for the final recording.)

Incidentally, I suspect the reason why some folks *think* they can hear the difference between 16 and 20-bit recordings (or other high quality formats such as SACD/DVD-Audio, etc...) is that if a studio is going to spend the effort to make an "audiophile quality" recording, they're also likely to carefully control all the recording equipment, from studio and mics, to mixers and cables -- whereas your typical 16-bit CD may come from an analog source, and/or use less than ideal recording equipment.

Scan through some listening tests over here for a bit if you're not convinced.

On a more serious note, I can think of two "must have" (for me) applicatoins that Windows has but lack on OSX. Firstly uTorrent. There's no equivalent on OSX and every single other torrent client is miles behind uTorrent.
Secondly, Foobar2000 - an extremely customizable database-driven music player with an insanely small memory footprint. It puts iTunes to shame. Take a look at this thread at the hydrogen audio forums to get an idea of just how customizable this program is. And remember, that's just the UI you're seeing, there's tons more that can be tweaked behind the scenes. Whenever I need to use iTunes, I feel like I have my hands tied behind my back.
Did I mention Foobar has a terribly small memory footprint too?

The sound quality issue isn't FUD; ATRAC (in its latest incarnations) is simply a better compression algorithm for audio quality (at comparable file sizes); see here or here for example. Now, I'm not saying you couldn't produce an MP3 which sounds better than ATRAC, but in common usage, ATRAC generally has more fidelity. Saying that, I'm sure as MD drops off as a format and MP3 becomes even more mainstream, MP3 will improve to the point that it overtakes ATRAC - and it's not a huge difference at the moment. But it's big enough for me - I didn't spend money on a decent hifi to waste my time listening to poorly compressed music on it. They're both compromises, but at the moment, in practical usage, ATRAC is less of a compromise than MP3.

A DVD player which plays MP3s is not an "MP3 player" - you'd have to use a computer to burn a CD/DVD specifically for listening on it. This is not the same as having one MD which I can use in a portable player or a deck. How many people do you know who keep their MP3 player contents sync'd with CDs ? If I'm listening to music while walking home, then decide I want to carry on listening to the same music, but on my hifi, I can simply take the disc out of my MD player, put it in my deck, and i'm done. With a computer based format like MP3 I'd need to burn it to a new medium first. Again, a computer is required. I spend all day in front of a computer - when I'm relaxing, listening to music, I don't mind using a cd player, but having to use a computer is an intermediate step i don't want.

Of course, with some portables you get a line-out which means you can plug it into your amp and listen direct from there, but not many come with a line-in which you can record via without using a computer. that's fine for many people, who want to use it via a computer. I don't.

And my MD portable IS a sony - an MZ-E909, at 71.1 x 77.6 x 12.5 mm (2cm smaller in height but 3cm wider, and about 5mm deeper - not that much difference - they both slip into a pocket easily). For that I get around 40 hours battery life (and more like 100 hours if i don't mind one AA battery piggybacking) - a nano gives about 14 hours. The build quality is also much better, IMO (magnesium shell - dropped many times with no ill effects, and even sat on a couple of times). So i get a slightly squarer, slightly thicker body, but only have to charge it every few weeks rather than every few days. Again, not a big deal, but it suits me.

I'm not saying MD/ATRAC is better than MP3 in all it's forms, it isn't - I'm just saying that it isn't quite the dead duck some people would have you believe - at least not in technical terms. For me, it's a great format, let down only by Sony's refusal to make it more mainstream. MP3 on MD could have been huge, if Sony had not been so dense a few years ago. Now anyone who hasn't already invested in the format would be mad to buy into it.

Replaygain is the solution to this problem- it allows for a regulated volume among all your music, and preserves all the differences in volume throughout a song or album. http://replaygain.hydrogenaudio.org/index.html

Ogg Vorbis uses more power and shortens battery life on DAP's worse than both WMA, WMA-DRM, AAC and FairPlay AAC.

This isn't exactly true. You might want to dig up some of the listening tests on this site.

I'll spoil it for you here anyway: there really isn't a clear winner. Depending on when the test was done and what bitrates they were looking at, different codecs come out on top. LAME was the king for a long time, but I believe Vorbis has surpassed it in most circumstances (as has Apple's AAC in a few). Basically, different codecs/encoders leapfrog each other. Vorbis hackers come out of the woodwork and start distributing patches that eventually get included in the official Xiph tree. LAME seems to always be under development, and there are efforts beginning to write version 4 which will de-gunk and modularise the source. As for Apple/MS/Nero, I don't know how much they improve their codecs, although I know AAC has improved since release.

Around the point of flac discussion, I switched to talking about how I wouldn't use alac encoding, which has a closed source encoding process (http://wiki.hydrogenaudio.org/index.php?title=Los sless_comparison#ALAC_CONS), which was my point of protest since I found it difficult to support use of the format using a non-Apple/MS operating system.

But thanks for the info on MP4/AAC, and I appreciate that it was a pretty misinformed post.

Links:
Latest Hydrogen audio listening test
Old but respectable: German computer magazine c't listening test

OK, this is rubbish for several reasons.

MP3 does not sound "noticeably worse"; all codecs have their artifacts at low bitrates. A well-tuned MP3 encoder like LAME in ~128kbps VBR mode will give very comparable results to AAC, with no statistical difference in a double-blind listening test. Hell, in an earlier test LAME beat WMA Standard (the most common version of the codec). And LAME in "--preset standard" mode gives nearly transparent results at around 180-200kbps.

AAC, WMA and OGG all have their advantages, but MP3 is truly a "jack of all trades". You want your audio to play in any player or portable you choose, like iTunes/iPod, WMP, Winamp, foobar2000, AmaroK, etc. etc.? You encode to MP3. Heck, both iTunes and WMP both ship with MP3 encoders now. Like JPEG, MP3 simply isn't bad enough to forsake compatibility for a superior codec.

Secondly, the author clearly doesn't have a solid background in audio technology. I am mystified as to why s/he thought he'd need "full-sized headphones" compared to Shure canalphones to hear the "benefits" of surround sound, when the fact is that with any stereo headphones more than 2 source channels of audio is essentially pointless!

As for surround sound systems, AC3 in the 384kbps+ bitrate is already the standard there. I can't see why MP3 surround will displace it; MP3 surround isn't, as far as I know, mentioned in any of the current or next-gen DVD specs.

OK, this is rubbish for several reasons.

MP3 does not sound "noticeably worse"; all codecs have their artifacts at low bitrates. A well-tuned MP3 encoder like LAME in ~128kbps VBR mode will give very comparable results to AAC, with no statistical difference in a double-blind listening test. Hell, in an earlier test LAME beat WMA Standard (the most common version of the codec). And LAME in "--preset standard" mode gives nearly transparent results at around 180-200kbps.

AAC, WMA and OGG all have their advantages, but MP3 is truly a "jack of all trades". You want your audio to play in any player or portable you choose, like iTunes/iPod, WMP, Winamp, foobar2000, AmaroK, etc. etc.? You encode to MP3. Heck, both iTunes and WMP both ship with MP3 encoders now. Like JPEG, MP3 simply isn't bad enough to forsake compatibility for a superior codec.

Secondly, the author clearly doesn't have a solid background in audio technology. I am mystified as to why s/he thought he'd need "full-sized headphones" compared to Shure canalphones to hear the "benefits" of surround sound, when the fact is that with any stereo headphones more than 2 source channels of audio is essentially pointless!

As for surround sound systems, AC3 in the 384kbps+ bitrate is already the standard there. I can't see why MP3 surround will displace it; MP3 surround isn't, as far as I know, mentioned in any of the current or next-gen DVD specs.

I tried that once and couldn't find the volume control. Have they fixed that? Is it a plug?

This is what I use:
http://www.hydrogenaudio.org/forums/index.php?show topic=28665

You need to use columns UI, but that's not a problem because columns UI is nicer than the default UI. Very configurable.

The newer generation iPods (the "2nd generation" iPod mini, the iPod nano, and the color iPods) DO have a significant flaw in MP3 playback that the Slashdot crowd is likely to be concerned with. You will not find this info in the iPod specs nor will you discover it by trying out an iPod at your local store. You will quite possibly find out when you start playing your own MP3 library on the device.

If you use LAME "alt preset standard" to encode your MP3 library (this configuration is widely believed optimal in that it produces very good sound quality at a reasonable bitrate) the newer generation iPods often have difficulty playing these VBR MP3 files when running from battery power. The flaw is essentially a type of "stuttering" or dropout that occurs during playback. The newer iPods apparently throttle the CPU clock to conserve battery power and if the MP3 bitrate ramps up too quickly this stuttering results. There is a thread about this on the Hydrogen Audio forms. It seems this has been known for quite some time but Apple has yet to release firmware updates that resolve this issue.

I started out using the 192k VBR MP3 encoder built into iTunes but noticed coding artifacts on some material. As an experiment, I thought I would try the LAME encoder to see if I could achieve better sound quality using preset standard. I think there is an improvement using LAME (no coding artifacts that I could hear so far) however the stuttering that results on some material is really pretty nasty.

I have both a 2nd gen iPod mini and an iPod nano so I can confirm that this is real and does happen on these units. The thread on the Hydrogen Audio forms seems to indicate that other current generation iPods have this problem also. I can live with the "scratching" issue on the nano (trust me, it is real.) However, the fact that the iPod doesn't work fully as an *MP3 player* kind of bothers me. The Hydrogen Audio thread is here:

http://www.hydrogenaudio.org/forums/index.php?show topic=37025

http://www.hydrogenaudio.org/forums/lofiversion/in dex.php/t33495.html

The newer generation iPods (the "2nd generation" iPod mini, the iPod nano, and the color iPods) DO have a significant flaw in MP3 playback that the Slashdot crowd is likely to be concerned with. You will not find this info in the iPod specs nor will you discover it by trying out an iPod at your local store. You will quite possibly find out when you start playing your own MP3 library on the device.

If you use LAME "alt preset standard" to encode your MP3 library (this configuration is widely believed optimal in that it produces very good sound quality at a reasonable bitrate) the newer generation iPods often have difficulty playing these VBR MP3 files when running from battery power. The flaw is essentially a type of "stuttering" or dropout that occurs during playback. The newer iPods apparently throttle the CPU clock to conserve battery power and if the MP3 bitrate ramps up too quickly this stuttering results. There is a thread about this on the Hydrogen Audio forms. It seems this has been known for quite some time but Apple has yet to release firmware updates that resolve this issue.

I started out using the 192k VBR MP3 encoder built into iTunes but noticed coding artifacts on some material. As an experiment, I thought I would try the LAME encoder to see if I could achieve better sound quality using preset standard. I think there is an improvement using LAME (no coding artifacts that I could hear so far) however the stuttering that results on some material is really pretty nasty.

I have both a 2nd gen iPod mini and an iPod nano so I can confirm that this is real and does happen on these units. The thread on the Hydrogen Audio forms seems to indicate that other current generation iPods have this problem also. I can live with the "scratching" issue on the nano (trust me, it is real.) However, the fact that the iPod doesn't work fully as an *MP3 player* kind of bothers me. The Hydrogen Audio thread is here:

http://www.hydrogenaudio.org/forums/index.php?show topic=37025

http://www.hydrogenaudio.org/forums/lofiversion/in dex.php/t33495.html

If it takes forever, chances are you have not configured the program correctly. EAC is not exactly the easiest ripper to configure. For a disc in decent condition, with EAC configured properly, EAC will rip in the same amount of time as CDex or any other ripper. If you need help, go to Hydrogen Audio.

Actually, I'd say the best use of EAC is to make the most of badly scratched discs. In this case, EAC will indeed take forever, but the results will be far less likely to contain audible problems. That's the 'secure' rip technology working.

They are known to be very, very bad... Read:

http://www.hydrogenaudio.org/forums/index.php?show topic=19777&hl=koss+plug

(look post #14 and #15)

Good choices seems to be the Sennheiser MX-300, MX-400 or MX-500.

There is also a good Panasonic, Sharp, and Pioneer in-ear phone for good price. Take a look at this thread:

http://www.hydrogenaudio.org/forums/index.php?show topic=26254&hl=under+$50

(Damn... I can't find those phones where I live)

They are known to be very, very bad... Read:

http://www.hydrogenaudio.org/forums/index.php?show topic=19777&hl=koss+plug

(look post #14 and #15)

Good choices seems to be the Sennheiser MX-300, MX-400 or MX-500.

There is also a good Panasonic, Sharp, and Pioneer in-ear phone for good price. Take a look at this thread:

http://www.hydrogenaudio.org/forums/index.php?show topic=26254&hl=under+$50

(Damn... I can't find those phones where I live)

I did blind experiments with LAME abr with a high-end sound card and Sennheiser headphones and I could not hear the difference from 160 kbps ABR. I must be deaf from having had 12 years of classical music education. 192 kbps is roughly --alt-preset standard which is generally agreed by the lossy sound compression community to be indistinguishable from the original for most (i.e. more than 50%) people.

Sure, two mediocre amplifiers will sound... mediocre.

Why would two mediocre amplifiers sound mediocre in exactly the same way? There is only one way for an amplifier to perform perfectly (output voltage same as input voltage apart from a constant scaling factor). There are infinitely many possibilities to deviate from this.

Here you go.

http://wiki.hydrogenaudio.org/index.php?title=Loss less

Microsoft never has cared much about audio quality with WMA, but Apple did make a serious effort to improve its AAC encoder in iTunes 6. In fact, it has improved to the point that it now produces quality comparable to Ogg Vorbis at equivilent bitrates. See http://www.hydrogenaudio.org/forums/index.php?show topic=38792

The real question though is did they re-encode all those songs on the iTunes Music Store with the new encoder?

The spyware that Sony installs on the computers of music fans does not even seem to be correct in terms of copyright law.
It turns out that the rootkit contains pieces of code that are identical to LAME, an open source mp3-encoder, and thereby breach the license

http://dewinter.com/modules.php?name=News&file=art icle&sid=215.

Sony rootkit violating GPL?, Seems to include parts of LAME?
http://www.hydrogenaudio.org/forums/index.php?show topic=38700

Depends on who is doing the mastering. There is nothing stopping a CD from having a 1hz or even 1/10hz signal on it. But, yes, the loudness wars games cause mastering engineers to kill the bass and do other nasty things to the sound like clippression. Thankfully, it seems that enough people realize these games ruin the sound of a CD that we are backing off from the excesses of the late 1990s and the early 2000s.

The best place to discuss this kind of technology is over at rec.audio.pro or on hydrogenaudio.

I didn't believe it until I got one (as a gift) but the shuffle has the best audio quality I've heard short of an external DAC into an spdif stream. its noisy (biased transistors in output stage?) but it has actual bass and enough drive to power headphones without distorting.
Interesting thread on DAP sound quality : here

• The loss from the mp3 encoding
• The loss from the ogg encoding
• The loss from the interpolation of mp3 and ogg encoding

• The loss from the mp3 encoding
• The loss from the ogg encoding
• The loss from the interpolation of mp3 and ogg encoding

That's a very, very, very, very bad idea. Let me explain why.

First.
Let me get some definitions straight:
mp3: Lossy format. Converting to mp3 means encoding your music. The best encoder is LAME (As proof, I suggest you check out hydrogenaudio)

ogg Vorbis: Lossy format. Converting to ogg means encoding your music. The best encoder is (offcourse) the original ogg Vorbis encoder.

mpc/Musepack: Yet an other lossy format. Converting to mpc means encoding your music. The best encoder is (offcourse) the original Musepack encoder.

flac: Lossless format. Converting to flac means compressing your music, as in: "I just compressed a text file, and did not lose any bytes in the file during compression". The best compressor for FLAC is offcourse the original FLAC Compressor.

Compressing: Making filesize smaller, without loss of data.

Encoding with lossy format: Making filesize smaller, at the cost of audio information.

Second.
To transcode your .mp3 files into .ogg, you'd need to first convert all of your .mp3 files into ogg. This would require the use of the LAME encoder (To convert the mp3's to wav), and then the ogg Vorbis encoder would have to convert all those wavs into .ogg format. You will lose all your id3 tag information.
Anyone who comes up with a simpler/faster solution (ie. "You dont need to convert to wav first!"), has very little to no insight into how digital audio encoding works, and what happens in the process of a transcoding/encoding/decoding.

Third.
If you convert from a lossy format to a lossy format, you will lose significant amounts of quality. DO NOT CONVERT FROM LOSSY TO LOSSY!
It does not matter if you convert a 320kbps mp3 into super-high-quality ogg - You still get huge amounts of loss due to the fact that the original material is lossy.

Fourth.
If you want to test out ogg Vorbis, then encode any of your legally bought hi-quality cd's to ogg, and listen to wether you like the result.

Fifth.
This should be obvious, but I'll tell you anyway: If you convert from lossy to lossless (ie wav or flac), quality will NOT increase.

Hope I could be of some informative value to you.

Not a system for everyone, since many students will be more interested in the big names which tend to get pirated in the first place, but a nice enough system, and the artists certainly aren't hard done by. They even provide software, MARS (Mindawn Audio Ripping Software), for ripping CD, WAV or AIFF to OGG or FLAC format for using with their system. That's not to say that you couldn't use flac/oggenc, especially since it isn't F/OSS, but it's nice that they've provided their own multi-platform utility with a GUI to help out in that regard... not to mention the fact that the MARS documentation says that you need oggenc/flac/cdparanoia installed on Linux in any case.

There's a nice piece of software that I use called Exact Audio Copy. It provides an amazing GUI that can be switched from noobie mode to ultra-1337, it can detect and correct errors on even really badly scratched CD's, provides online CD database access, custom naming schemes, lots of ID3 tag options, and you can encode to *any friggin format you want to*. It has built-in support for a very large number of formats, but you can also integrate it with LAME, oggenc, flac and whathaveyou. Oh yeah, and it's free too. Windows only, but it might work with wine on linux.

Also, if you want more bang for your buck, er, download, Rarewares has special builds for oggenc, flac, and other formats that support a larger number of features. For instance, they added hard min-max bitrate levels for ogg vorbis (so ogg doesn't encode silence at 100kbps), and something called "impulse-trigger", which helps with promblems in echo from rimshots or something like that. The forums at hydrogen audio explain the extra features in more detail.

Because I love recursion, here's a link to the Hydrogenaudio post discussing this comment.

http://www.hydrogenaudio.org/forums/index.php?show topic=34368&st=0&p=310943&#entry310943/

Then [after making modifications] spin a disk on auto-repeat for a day or two to "burn-in" the unit; the sound will surely improve during burn-in.

And I also hear the sound-enhancing fairy named Audiophile will visit during that time.

The tone had been slightly light. Modification increased the body of the tone--for example, a guitar sound that previously was all string now includes the wood of the instrument. The stock unit had a bit of congestion on dynamic passages, especially evident on massed strings. Not anymore; the top and bottom ends are detailed, extended, and inviting. [bla bla bla]

In all likelihood, you'll agree that the project was well worth the effort. Maybe it was even a learning experience.

After spending a few hours of your time, you probably will want to feel it was worth the effort. A real learning experience would be to then run an A/B/X test and show how many of these enhancements you're imagining. Swinging over to the Hydrogen Audio listening tests forum would be a start.

It's like having a slow program, finding code that you think is a cause, making changes, but never measuring the actual difference the changes make.

I would give most anything for a working media player for OS X that plays oggs, flacs, and maybe shns.

Merry Christmas. Seen on HydrogenAudio -- the owner of that forum, Dibrom, is also looking at writing his own Mac player.

I would give most anything for a working media player for OS X that plays oggs, flacs, and maybe shns.

Merry Christmas. Seen on HydrogenAudio -- the owner of that forum, Dibrom, is also looking at writing his own Mac player.

Maybe this is news for Winamp users - I doubt it, but I don't use it myself. But there has been software to download songs from the iPod to your harddrive for ages. The inability to do so is pretty much limited to iTunes, every other application dealing with the iPod (and there are dozens) enables you to do that. One popular example for Windows is EphPod. Lots and lots more can be found for multiple platforms at iPodlounge.

Personally, I use foo_pod, a plugin for the foobar2000 audio player. It's quite powerful, including such features as automatic conversion of formats the iPod doesn't know (e.g. ogg or shorten) and automatic generation of audiobooks. For what it's worth - Wired seems to care - foobar and foo_pod are yet half as small than Winamp and that plugin is. Hah.

Ogg Vorbis support might be nice, since it's one of the better streaming formats available...

Listening tests:

HydrogenAudio - The Autov tweaks made it into the official releases. (1.1)

(I can't find anymore at the moment, feel free to add your codec tests. The tests done via HydrogenAudio are generally considered to be solid.

Thanks

Jan

1- Yes I do know
2- No, mp3 encoding has very specific losses and artifacts on quite a lot of frequencies of the spectrum (do visit the HydrogenAudio forums for more informations) and doesn't even remotely compare to lossless even with very high bitrate (said bitrates yielding higher data sizes than good lossless codecs BTW)
3- Recompression from lossy mp3 to any other lossy format yields artifacts and data loss exponentially higher than the artifacts and data loss of any of the two lossy codecs

MP3, even at high bitrates, is nowhere near CD quality or lossless quality, which is in itself quite far from the "theorical analogic" quality (said theorical analogic being when not taking in account aging and physical artifacts of LPs, since it's the most common analogic music medium)

You should really try Foobar2000. Just like iTunes, it is built around the concept of you never having to worry about individual MP3s, but unlike iTunes it has a massive customization potential, along with an MP3 tagger infinitely more powerful than anything I've ever used(and I've used quite a few different ones, including commercial applications).

For proof of the customizability of Foobar, just check out the gallery posted on their forum. No two foobars are the same =) No, I'm not affiliated with the foobar in any way - I'm just trying to open people's eyes for this wonderful program; I was doing the same thing with firefox until I got everyone I know to switch - when another solution is a lot better I just feel compelled to annoy people until they switch

Refer to the lossless codecs comparison on Hydrogen Audio.

Personally, I'd go for Wavpack due to its excellent compression, non cpu-intensive decoding, cross-platform support, active development and open license. If the Rockbox project succeeds, I'll be able to play them on my iRiver.

http://www.hydrogenaudio.org/forums/index.php?show topic=32440

The site insists on proper ABX tests too, not some thirteen olds insisting they can tell the difference between FLAC and Monkey's Audio codecs.

Why can't you re-rip to Apple Lossless format? There's an open source (ALAC) decoder for it now.

The foobar2000 audio player includes built-in support for ReplayGain. MP3 Gain was mentioned in another thread, for the differences, see Difference between Mp3gain and Replaygain.

You really should be asking this over at Hydrogenaudio:
http://www.hydrogenaudio.org/forums/index.php
The signal to noise ratio is much better there for this kind of question.

Even if you use VBR (variable bit rate) compression, the algorithm still tries to average a certain overall bitrate, so the result is the same. It would be nice if you could just say "compress this song using as many bits as you need to make it sound good," but unfortunately the phrase "to make it sound good" is very subjective. The algorithm doesn't know what sounds good.

Bzzt. Wrong. VBR schemes in formats such as OGG, MPC, and others are based on "quality" as opposed to bitrate. There's certainly a correlation between the two, but the idea is to have compression levels linked to quality as opposed to size.

Even with MP3 you can have VBR encodings that go down to 32 bps during silence. Check out LAME's "alt-preset" (just preset in recent revisions) command line options for damn good quality based settings.

See Hydrogen Audio for more information than you could ever want.

This is only true for lossless codecs. This won't work for any lossy codec. You can't go from MP3->WAV->MP3 for example without quality loss. Same with WMA, AAC, and pretty much all the popular lossy codecs. For more information, see this discussion on HydrogenAudio.

• MusicBrainz
• MoodLogic
• QuickNamer
• MusicMagic Mixer
• UltraTagger
• FixTunes
• Tag&Rename

Apparently the Shuffle may not be immediately compatible with linux tools already available. Gnupod apparently has trouble copying music to the shuffle.

According to the author of foo_pod for FooBar2000, there's the usual iTunesDB database, but also a new one, called iTunesSD. They haven't been able to completely reverse-engineer this one yet. It turns out it isn't sufficient to simply write to the iTunesDB database -- songs won't play.

Searches on Google show nothing about the iTunesSD database.

Apparently the Shuffle may not be immediately compatible with linux tools already available. Gnupod apparently has trouble copying music to the shuffle.

According to the author of foo_pod for FooBar2000, there's the usual iTunesDB database, but also a new one, called iTunesSD. They haven't been able to completely reverse-engineer this one yet. It turns out it isn't sufficient to simply write to the iTunesDB database -- songs won't play.

Searches on Google show nothing about the iTunesSD database.

From Gizmodo, and a rebuttal. There is also a way to do it, albeit with a hack.

Engineer Dastardly Slaphapple took a break from his day job as a hardware and firmware designer at Bumbrubbley Audio Studebakery (maker of the iPod competitor Slompet player, among other things) to give us some more info on the OGG-on-iPod plausibility, including why the iPod mini (and future iPods) might have a better shot at getting OGG support than the older, whiter iPods. There's even information about why Apple may have chosen to implement their 'Lossless AAC' instead of the more widely adopted FLAC lossless format.

Dastardly's analysis after the jump:

Firstly, CPUs:

The current iPod gen3 has a PP5002D CPU, the same as the gen1 and gen2. The gen1/2 stored their code from flash, not SDRAM, meaning they had a more limited codesize, and their SDRAM took more power to operate.

The iPod mini has a PP5020 CPU

The Rio Karma (developed in Cambridge UK) uses a PP5003 CPU. It plays OGG (and FLAC and MP3 and WMA).

The old 5002:

The 5002 has a "broken" cache (1 wait state per access for program or data, meaning you effectively have half the effective clock rate when running code from external memory). This means that running code that doesn't fit in the internal 96kbyte SRAM of the player is very inefficient, both in terms of CPU cycles and power. MP3 and AAC just about squeeze into the internal memory (one at a time, obviously!), but anything that didn't would result in a big power hit - my guess is 30-40%+. This would be a bad user experience, considering the already short gen3 battery life.

The newer 5003:

The 5003 in the Karma has this particular silicon deficiency fixed. The Karma plays OGG, though it's still a resource hog - you get about 25% less battery life - about 11-12 hours compared to 15+ for MP3 due to the extra cycles and memory requirements when compared to the more svelte codecs. We didn't do a lot of optimisation, so it's running the Vorbis-supplied tremor decoder with only a few tweaks.

The even newer 5020:

The 5020 is based on the 5003, and so has the cache bug fixed. It's capable of playing OGG with 25% or less hit on power (depending how much optimisation is done). I would suspect the 5020 will find its way into the next iPod, as it's cheaper and integrates both the firewire MAC and the USB2 mac/phy blocks which are separate chips on the gen3.

So in summary:

gen3 - In theory possible, but unlikely. mini - Very possible. gen4 (or my guess at what a gen4 would have in it) - Very possible.

Dastardly Slaphapple is not speaking for his employer Bumbrubbley Audio Studebakery or Slompet Heavy Industries or anybody else. He's just sharing.

Any other resources that Slashdot readers can recommend for those who are interested in the subject of audio compression and representation?

• An older but good technical survey of digital audio compression, including MP3, is Davis Yen Pan, "Digital Audio Compression," Digital Technical Journal (Spring 1993). (PDF)
• Some other technical reference material on MP3 is also available on the Digital Audio Systems website.
  
• A more recent survey of perceptual coding of audio, which covers more recent formats like AAC, is Painter and Spanias, "Perceptual Coding of Digital Audio," Proc. IEEE (April 2000). (PDF)
  
• Ogg Vorbis is documented on the Xiph.org website, but I found the documentation to be lacking when read from a signal processing perspective. Christopher Montgomery provides a better description from that perspective in a Slashdot interview from 2000. I found another good description in this thread in the hydrogenaudio forums--it hyperlinks a good block diagram of the encoding process.
  

Did you try an optimized encoder? Ogg Vorbis optimized for speed, ca. 1.5x faster than 1.1 original ver.

You're half-right. Burning to CD does not, indeed, degrade the signal any. However, re-encoding the track with ANY lossy codec (AAC included) will degrade the quailty, as the waveform will have bits of it stripped out twice. The only real (read: significant to audio quality) differences between AAC and MP3 are the psychoacoustic models used, and the bit-packing methods. Which is better is an argument for these folks, but the fact remains that both are lossy codecs, and therefore suffer from the re-encoding entropy problem.

• Short answer:
  • You should test them yourself, and choose which one best suit your needs.
• Somewhat long answer:
  • For best possible quality: Lossless (WavPack, FLAC, Monkey's Audio)
  • For highest quality @ high bitrates: Musepack (MPC)
  • For overall high quality, even at lower bitrates (96 ~ 160kbps): Psytel AAC, Ogg Vorbis
  • For best compatibility: Lame using --alt-presets
  • For very low bitrates (<64kbps): MP3pro, Ogg Vorbis, WMA, Real Audio.