iTunes Match Bitrate discrepancies...

To be honest, I wasn't even considering lossless. It isn't an issue to me at all, and the OP was talking about 320kbps MP3's.

What you say is very true, but I didn't think it really related to the issue.

I have very few MP3's and those that I have uploaded have all been preserved, as happened with Roebeets. That isn't to say that in some cases they may be converted. My belief is that at more then 320kbps (I don't even know if that's possible) theu would be converted.

Edit: Actually, I just noticed that the OP said "I've read that 320k or higher bitrate files that are uploaded would be preserved". I didn't notice the "or higher" bit earlier. I suspect that is his problem. I apologise, I thought he was specifically talking about 320kbps, which I believe are preserved.

You're right, KeithJenner. The OP talked about MP3 files. It's an old work habit, but I always try to anticipate what other people reading a post might be dealing with and take that into account in what information I provide.

I'm not so into file formats that I know how many people use 320kbps MP3 files, but I do work with lossless as part of my vinyl ripping workflow and I know why people want lossless. My gut tells me the key here is lossless is a non-starter with Match. Sounds like Michael's proven that to be the case.

I've even got a few that were over 200 MB, and transcoding them made them small enough to upload.

Michael, you're saying Match transcoded the 200+ Mb files, that you didn't do it yourself? If that's the case, then I think that, as my late father would say, constitues "news." Good news at that.

Based on what I've read in this thread from roebeet's testing, it seems that any lossy files, up to 320 Kbps are uploaded as-is, while lossless files will be transcoded in the background and those files will be uploaded. I'd be curious to know what happens if the import settings are set higher than 256 Kbps iTunes Plus in iTunes. I'll have to try that later today.

@Jim in regards to testing lossless uploads: Yeah, I didn't test ALAC / AIFF / WAV as I figured they had to be transcoded on upload - it's what Apple's doc states. But I should try that myself just to be sure.

As for other lossy file formats, WMA's get transcoded on import in Windows (MacOS doesn't even support them, at least not OOTB) and Vorbis has problems importing. So I can't really test those. I figured MP3's and AAC's would be what most people use with iTunes anyway, at least for lossy files.

I also want to download a few Amazon Cloud files to see if they are intact, even the metadata. We now know that Apple alters the metadata on uploads, and even adds your Apple ID if it's an AAC file. But I have no idea if Amazon does something similar.

Michael Allbritton wrote:

I'd be curious to know what happens if the import settings are set higher than 256 Kbps iTunes Plus in iTunes. I'll have to try that later today.

256kbps is the highest bitrate you can set in iTunes

I think it's fairly safe to assume that the only formats which will upload without conversion are AAC and MP3 (up to 320kbps), for the reason that they seem to be the only lossy formats that devices like the iPhone can play.

I'm sure lossless is converted due to storage/bandwidth issues.

320kps AAC's get uploaded as is, and do play back in the iTunes app at least - I specifically upped the limit on my test file yesterday to 320kps (I used Nero Encoder and not iTunes for that test file). As for iOS devices, again I don't know. Maybe I should buy an iPad. 🙂

That's correct. Jim. The process was automatic and happened in the background.

I suspect, but haven't tested this yet, that the background transcoding for lossless files will use whatever import settings are configured in iTunes. So, for example, if someone is using 320/MP3, then that is what will get uploaded. But I've got to find something to import that I haven't run throught iTM yet and I know will not match. May be time to buy a new Phish show. 😁

KeithJenner wrote:

256kbps is the highest bitrate you can set in iTunes

I just double-checked, Keith. You can set the bit-rate up to 320 for AAC and MP3.

According to the quote from the support document Jim posted earlier, they are converted to 256kbps AAC's

Apologies Michael. I checked too but didn't notice the "Custom" tag at the bottom. You are correct.

I know. But I wonder if that KB doc is assuming a default setting of 256 Kbps iTunes Plus in the import settings. Later today I'll do a bit of playing around with the import settings and ALAC files and see what I find out.

OK, Michael. Then Apple doesn't check file size on file types it flags for transcoding, but does I imagine, do it on the transcoded version before it's cleared for uploading. That's an important piece of information.

A live Phish concert. I haven't been to a live concert since the 80's. No wait, ZZ

Top at an outdoor ampitheater at an Indian casino west of Tucson counts. That was only a few years ago.

To anybody who cares - this is my b-day. 59. I'll be trying to enjoy the day, No Bali, nor Phish for me, but still I think I'll get outta the house!

Quick test on my part -- had my local iTunes set to AIFF import, first off. Imported a 48khz WAV (again, an obscure artist from a needle drop that I was certain would upload), then did my upload. Then downloaded that new iCloud file to compare.

It's not only a 256kps AAC, as we expected, but the local app on my PC wrote the file (it lists the writing application in the metadata). And the uploaded file also has my Apple ID tagged in the metadata as well. Lastly, it's 44khz and not 48khz, so it does re-sample before upload, if it's a lossless transcode. This is all stuff I expected, given what we already know.

I also grabbed a few Amazon Cloud uploads, just as a comparison (they support AAC and MP3 uploads, and can handle 48khz files as well). The uploaded file and the original are bit-for-bit the same, even the MD5 sums are identical. So Amazon isn't touching those files. Just an FYI.