Axiom Home Page Forums General Discussion Technical Questions Itunes, bitrate, and other questions...

OK, so I started using Itunes recently. Yes, I know...get with the 2000's Randy, lol.

Anyway, I am planning on buying an external storage drive to store my CD's, Vinyl, etc. If I use a higher bitrate or lossless format for my local Itunes copies for the best quality when playing over my M80's, can I synch easily to a portable device (Ipod, mp3 players) in a lower bitrate to save space on the device? I see where I can experiment with various encoders and bitrates in Itunes, but can't see where the import bitrate setting would be different than what I put on a portable player.

One way is:
1. Import first in lossless.
2. Change the import settings for a lower bitrates.
3. Right-click on your songs and select "create MP3 version" (or whatever the format you choose).
4. Itunes will create a copy.
5. Rename the album of the new tracks from "Regina Specktor" to "Regina Specktor (ipod)"
6. Create a "smart playlist" called iPod for all "albums" contains "(ipod)"
7. Select "manualy sync" when syncing your iPod and select the "iPod" playlist.

This sounds like a lot of work, but it is actually not that bad and you do it only once.

That does not sound to bad Eric, so by doing this I will have two copies on my hard drive, one lossless (or higher bitrate) and one at the lower bitrate that I synched to the Ipod?

Or, is there some way when you make a copy to have it copy to the IPOD, or can you drag/drop? Just looking for options.

I was thinking about using MP3 320 CBR for my main copies, as from what I have read in blind tests, most people can't tell the difference between anything above 256 and CD quality.

For the Ipod copy I would probably use 128kps VBR

Is lossless "really" lossless?

Just a general question.
I've had some discussions with some rather brilliant computer engineers and programmers (you know, the kind of guys who learned how to build circuit boards at the age of 12) simply stating 'any compression format can be assumed to induce errors by its very nature of how they compress data'.

if the original waveform can be reconstructed, then it's lossless. I've never seen an error analysis for any lossless format, though.

CV bait.

I don't know what those guys were doing, but at 16 I was designing lossless packing algorithms for 2D graphics. I know for a fact that RLE (run length encoding) and dictionary pattern matching are lossless. They are also blindingly obvious, and a 16 year old could come up with them on his own.

Lossless audio is somewhat more complex, but I still have no doubt that it can be done without introducing error. One of the usual methods is to write an prediction algorithm which tries to guess what value will come next based upon previous. If it's right, then nothing needs to be stored. If it's wrong, then the difference between the predicted value and the actual value is stored. The error is the data.

Properly implemented, there are many ways to reduce the redundancy in data, that when undone presents an exact copy of the original. One thing, in packed form damage to the data will be more extensive when unpacked. But that's not a failure of the compression, but of the transmission/storage medium. And why we have error checking and correcting.

They were talking about lossy encoding. 'by its very nature' zipping remains zipping while 'by its very nature' jpg/mp3 loses data. How much data did you loose so far with zipped files? If any, it was the result of hard drive failures, not the unzipping process.

Any other input on my questions.

Eric's method is what you're going to have to work with. If (and unfortunately only if) you're syncing songs to an iPod Shuffle, then iTunes offers an option to convert songs to 128 kbps AAC on-the-fly.