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Topic: Lossless AAC? (Read 87009 times) previous topic - next topic
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Lossless AAC?

Reply #50
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The part I'm interested is Lossless AAC encoding. I hadn't even heard of this until now. Does anyone have any info on it and how it compares to other lossless encoders?

There is no such thing, unfortunately.

What exists is MPEG4 ALS (Audio Lossless Coding), which was mostly developed by the same author of LPAC
http://www.nue.tu-berlin.de/forschung/proj...s/mpeg4als.html

But, as far as I know, standardization is still going on for this project. I don't think Apple would use it before being ready.

The other alternatives would be a proprietary codec developed by Apple that they call "Lossless AAC", or they are going to sell high bitrate standard AAC files and claim they are lossless (highly unlikely too).

I can't imagine what else could be going on.

Of course, another alternative would be that this "leakage" is partially fake or erroneous.

Edit: Didn't you see, by any chance, any hint about when iTunes 4.5 will be released?

I contacted the author and he says, MPEG-4 ALS file format will be freezed
either at the 116th or the 117th AES Conference.

116th:  May 8-11, 2004
117th:  October 1-3, 2004

Hope this information helps.
--  Frank Klemm

Lossless AAC?

Reply #51
can someone post/host a clip? (preferably unadulterated, I can't read .rar)

nothing about FLAC prevents apple from using it exactly as is (or wrapping it in fairplay), or tweaking it slightly to make it incompatible.  doing that without attribution would be pretty slimy though.  I haven't heard anything from apple about it.

if it's (mostly) FLAC I should be able to tell from an un-DRMed clip.  also tell me the stream parameters (bps, channels, sample rate, exact number of samples or approximate length in sec) and any encoding parameters.

Josh

Edit: PS please also post the original clip (wav or aiff)

Lossless AAC?

Reply #52
Update: Answered my own question. It appears Apple has a new firmware update out for iPods to play the new Lossless format.

http://www.apple.com/ipod/download/

Has anyone tried this firmware update yet to see if it plays Lossless files OK on iPods and Ipod minis?

Lossless AAC?

Reply #53
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can someone post/host a clip? (preferably unadulterated, I can't read .rar)

Reading RAR is pretty easy in nearly every popular platform.
http://www.rarlab.com/rar_add.htm

Anyway...

Here is an Apple Lossless sample. It's inside .MOV because I saved it from QuickTime. Demuxing it is trivial.
http://www.rarewares.org/rja/OrdinaryWorld.mov

The same sample, in FLAC:
http://www.rarewares.org/rja/OrdinaryWorld.flac

Lossless AAC?

Reply #54
thanks.  how do you demux the .mov in linux (or freebsd)?

also the original wav/aiff would help a lot.

Josh

Lossless AAC?

Reply #55
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can someone post/host a clip? (preferably unadulterated, I can't read .rar)

nothing about FLAC prevents apple from using it exactly as is (or wrapping it in fairplay), or tweaking it slightly to make it incompatible.  doing that without attribution would be pretty slimy though.  I haven't heard anything from apple about it.

if it's (mostly) FLAC I should be able to tell from an un-DRMed clip.  also tell me the stream parameters (bps, channels, sample rate, exact number of samples or approximate length in sec) and any encoding parameters.

Josh

Edit: PS please also post the original clip (wav or aiff)

Liebestod.m4a
Liebestod.wav

I think you can find most info you requested by looking at the original wav file. There are no encoding parameters. The only choice for encoding is "automatic". It's 921 kbps according to iTunes.

Lossless AAC?

Reply #56
perfect, thanks, I will take a look.

Josh

Lossless AAC?

Reply #57
According to Slashdot at:
http://apple.slashdot.org/apple/04/04/28/1...tid=185&tid=188

The new iTunes appears to "break" the old DRM sharing software. Does this mean they are using a different DRM model in the new iTunes and will old software no longer work? Anyone know anything about the new DRM model?

Lossless AAC?

Reply #58
RealPlayer 10 has had lossless encoding for awhile.  I'm guessing it's similar to what Quicktime has.

Lossless AAC?

Reply #59
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I'm guessing it's similar to what Quicktime has.

Probably not.

OrdinaryWorld.wav: 4879Kb
OrdinaryWorld.mov: 3326Kb
OrdinaryWorld.ra: 3278Kb
OrdinaryWorld.flac: 3.301Kb

Lossless AAC?

Reply #60
OK, after doing some analysis, I realized it would help more to create some specific files and ask you guys to encode them and upload the results here (or host somewhere else).

there are a few wavs (packaged two ways) here:

http://flac.sourceforge.net/landfill/testwavs.tar.gz
http://flac.sourceforge.net/landfill/testwavs.zip

(if anyone knows a free tool to make stuffit files on linux let me know, or if there's any other package format that's better.)

now if someone could encode each wav to "apple lossless" (no .mov, just .m4a) and put them somewhere that would help a lot.  also, if there are any encoding parameters, use the same parameters for all encodes and describe what they are.

thanks.

Josh

Lossless AAC?

Reply #61
but is it gapless?

Lossless AAC?

Reply #62
You can find those test files encoded with Apple Lossless here:

http://www.hydrogenaudio.org/forums/index....ST&f=35&t=21170


They were encoded with iTunes 4.5 on Mac OS X 10.3.3

The only possible setting for Apple Lossless in iTunes is "automatic".

Lossless AAC?

Reply #63
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but is it gapless?

No, it's still not gapless.

And the 3G iPod firmware was updated to allow playback of these new lossless files. Of course that will kill your battery life and greatly reduce the number of songs you can put on the iPod, so I don't know who will use it.

The holy grail, IMO, is to encode lossless on the computer and re-encode on the fly to something like 128kbps AAC-LC when transferring the files to the iPod. As it is, my enthusiasm for this new format is pretty low.

But I'm still curious as to the origins of this codec. It seems irresponsible and unwise of Apple to neither wait for the official MPEG4 lossless codec to be defined nor take advantage of FLAC.

Lossless AAC?

Reply #64
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The other alternatives would be a proprietary codec developed by Apple that they call "Lossless AAC", or they are going to sell high bitrate standard AAC files and claim they are lossless (highly unlikely too).

now THAT is what i'd be interested in. 99 cents is in one sense a pretty good deal (i paid $2.50 once to Liquid Audio for the one track i bought from them), but i'd pay maybe as high as $1.50 for a lossless track

Lossless AAC?

Reply #65
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but is it gapless?

No, it's still not gapless. 

Noooooooooooooooooooooooooooooooooooooo...

I though this would make the iPod a better choice than the Karma becuse of it's construction and HD size.  Oh well...  Guess I'll keep waiting for the next generation Karma.

Lossless AAC?

Reply #66
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but is it gapless?

iTunes also still has a small gap between Apple Lossless files (or any other format for that matter). I am still very sad about that. Time to write another email to Apple.

Lossless AAC?

Reply #67
Did you try the "Handy Concept for Concept Rock" described here :
http://www.apple.com/itunes/import.html

I don't really know if it helps, or how it works (I can't test for the moment). Does it work on import only? Does it also work with lossy encodings (with gaps/silent frames)?

Lossless AAC?

Reply #68
My findings:

Apple lossless is not FLAC.

Maybe they are using some techniques from FLAC, and nothing about FLAC prevents them from doing that, but I can't tell from analyzing bitstreams.

I can see that there are some techniques they are not using that will hurt the compression 5-10% for some kinds samples.

Even though Speek's comparison shows that it compresses a little less than FLAC in general, I doubt this will be much of a hinderance.  Popularity is going to come mainly from usability and Apple has that: the #1 online distribution service and #1 portable player.

It's disappointing that they went with a proprietary codec that performs worse than FLAC (ratio, decode speed/complexity).  I don't see much of an advantage; I don't think there's any technical reason they couldn't have wrapped FLAC in FairPlay, but they never asked.  Oh well.

Josh

Lossless AAC?

Reply #69
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... I don't think there's any technical reason they couldn't have wrapped FLAC in FairPlay, but they never asked.

Out of curiosity, what would be the advantage of wrapping any lossless codec in FairPlay? Once decoded to WAV, or burned to a CD (both of which should be quite simple) the WAV could be re-compressed to any other lossless format, sans DRM.

    - M.

Edit: Fixed a silly spelling error.

Lossless AAC?

Reply #70
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Did you try the "Handy Concept for Concept Rock" described here :
http://www.apple.com/itunes/import.html

I don't really know if it helps, or how it works (I can't test for the moment). Does it work on import only? Does it also work with lossy encodings (with gaps/silent frames)?

Yes, it only works on import, and it's quite stupid. Basically it merges several tracks into a single file, and you can see the limitations that would imply.

Lossless AAC?

Reply #71
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The holy grail, IMO, is to encode lossless on the computer and re-encode on the fly to something like 128kbps AAC-LC when transferring the files to the iPod


Absolutely. This is the ONE feature that Windows Media Player has that rocks. 200 GB HDs are common now for PCs. This allows one to store their collection on their PC in lossless and encode to 128 AAC on the fly for transfer to a portable that has 4GB or 20GB. I really hope Apple implements this. Losselss is great for making mixed CDs to play on state of the art sound systems, but its really not practical (or needed) for a portable with a pair of ear buds. It kills the battery and take sup too much HD space.

Apple Lossless is not gapless????? Why would they not implement this????

I's be shocked if we see lossless in the iTunes music store.

Lossless AAC?

Reply #72
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Apple Lossless is not gapless????? Why would they not implement this????

There may be no way to play the Apple Lossless file without a gap (iTunes and iPod), but it is gapless if converted back to WAV and it matches an md5 of the original WAV. Someone mentioned earlier that WAVs play with gaps on the iPod, so this is where the problem lies, not the file itself.

Lossless AAC?

Reply #73
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Apple lossless is not FLAC.

It's disappointing that they went with a proprietary codec that performs worse than FLAC (ratio, decode speed/complexity).  I don't see much of an advantage; I don't think there's any technical reason they couldn't have wrapped FLAC in FairPlay, but they never asked.  Oh well.

I know, that I know nothing (Socrates)

Lossless AAC?

Reply #74
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QuickTime Pro does the decoding job. But it seems to me there's a bug. Decoded files are some frames shorter than the original WAVE file. I've tested this with EAC's 'WAV compare' tool.

In which case, we can't really call it lossless anymore, can we?