A question about Apple Lossless

Ronald Epstein · 02-27-2008, 10:56 AM

I already have my iTunes filled with songs that
have been downsized to 128 or 326 bitrate during
the CD -> iTunes process.

I am in the process of starting all over again as I recently
discovered the Apple Lossless selection.

However, I noticed if you right click on a song that is in
your existing library at 128 or 326, you can convert to
Apple lossless

What does this mean? How can it convert a song dumbed
down to 128 bitrate back up to a lossless format with the
expectation of better sound quality?

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Cameron Yee · 02-27-2008, 11:42 AM

Ha. I'm doing the same thing, but only doing the material I want to listen to on a regular basis. I learned that I don't really need ALL my stuff accessible this way (e.g. Christmas albums and collector, novelty stuff).

My assumption with the lossless option with already compressed files, is that it's just not compressing things further. Sort of like opening a JPG in Photoshop and then saving it as a TIFF or PSD so that you're not compressing things further in your editing. The goal is not to have it look less compressed, just not any more compressed. But I'm not sure of the point with the iTunes file since you're not doing any editing of it. It just seems like a way to save space if that file happens to be really large.

Ronald Epstein · 02-27-2008, 11:44 AM

Cameron,

The worst thing about importing all this stuff in LOSSLESS
is that I understand you don't get song/track tags included.

I may be wrong because I'm ripping CDs that were converted
from MP3s so I think all that information was lost anyhow.

Cameron Yee · 02-27-2008, 11:48 AM

Yeah, that's a pain. I believe if you had selected "include CD Text" when you burned the CD, you would have all that info. In my case, most of my stuff originated from CDs, so I haven't had to deal with that. The album artwork retrieval can be pretty inconsistent though.

Ronald Epstein · 02-27-2008, 11:52 AM

That CD text is only an option when burning to a CD -- not
importing from a CD in lossless audio. At least, that is what
I see here.

Cameron Yee · 02-27-2008, 12:09 PM

If you are encoding from commercially purchased CDs you should be getting all the album info. If not, there's a setting under Advanced>Importing to automatically retrieve that data.

If you burned an audio CD from compressed files (which is how I interpreted your issue), then (I think) unless the CD Text option was selected to begin with then those track names are lost.

Zack Gibbs · 02-27-2008, 01:19 PM

Ron, converting a lower bitrate mp3/AAC file to lossless will garner you no improvement, resulting in nothing more than the same file at a much larger size.

If the CDs you're importing are burned CDs from MP3s, then importing them again seems a waste, though there could be some improvement. Do you have access to the original MP3's? Those would sound identical to your lossless rips and be much more compact.

Ken Chan · 02-27-2008, 05:49 PM

In order to play an MP3, the MP3 decoder has to decompress it. If you then compress that with any lossless encoder, it will perfectly preserve all the original MP3 flaws in a much larger file.

If you had a song compressed in a format that you no longer want to use, or your player does not support, then to avoid degrading the song further by recompressing in another lossy format, compressing with lossless makes sense.

Otherwise, there is no point.

Joe Casey · 02-27-2008, 08:24 PM

Apple Lossless, or ALAC, is Apples equivalent to FLAC i.e. they are both lossless compressed formats. AIFF and WAV are lossless uncompressed formats. MP3 and AAC are lossy compressed formats. Theoretically ALAC is identical to AIFF, as FLAC is to WAV, the only difference being the amount of disc space they occupy. Metadata, or ID3 tags, are retained as part of the file structure for all formats I've mentioned except for WAV as far as the ripping process is concerned. Burning these formats to a disc does not automatically include the metadata unless the burning software is specifically told to do so.

To answer your original question, converting lossy formats to lossless formats will not get you any enhanced quality for playback. The information that was removed during the lossy conversion is gone and cannot be retrieved.

Also, in iTunes, the right-click conversion (or Advanced -> Convert Selection to......) is dictated by your import settings (Preferences -> Advanced -> Import.......). If you change these settings to, for example, AIFF, then the right click conversion (as well as the Advanced -> Convert......) will convert to AIFF as well.

Ray Chuang · 02-27-2008, 09:07 PM

In my personal opinion, unless you have an iPod 5.5G or iPod classic with at least an 80 GB hard drive, using the Apple Lossless format isn't that useful because you only get circa 50% reduction in file size compared to the original on a Compact Disc, which means you can store relatively few albums on these iPod models. The format, however, is quite useful for archiving Compact Discs on a higher-capacity external hard drive, though.

I find 256 kbps AAC VBR encoding to work very well, since it offers very good file compression (important for flash memory iPod nanos, the iPod touch and the iPhone) and the sound quality is excellent for most iPod listening.

TonyD · 05-03-2008, 08:00 PM

what does variable bit rate do.
or why should i enable it?

Adam Lenhardt · 05-04-2008, 03:17 AM

What it does is look at the data and distribute the bits to the areas of the song that need it most. So a 128kb variable bitrate song will average out to a 128kb bitrate, with some points encoded higher than that and other points encoded lower than that.
I don't trust it myself, and encode everything 256kb-320kb constant bitrate.