Nope! I had a couple with screwed up tags that had to be uploaded, once I correct the tags and updated match, their status then changed to matched, so it doesn't appear it reads anything but the tags. They were common songs, so if it checked other stuff, they would have been matched to begin with.
It has to look at both meta-info and actually scan the files. It's probably like how youtube and facebook do it. They scan your (in this case videos) and will recognize songs in them and give you copyright notifications.
If it only looked at metadata info, what's stopping me from renaming all of my files to songs I'd like for free and then hitting "update iTunes Match"?
I would bet anything it first scans the files like shazam/soundhound. If a 1-for-1 match is made, it goes with it. If a 1-for-1 match isn't made, it probably looks at the metadata to narrow it down or something. But there's no way just metadata will get a match. Try it - change one of your songs to another song title (and update it with the wrong/proper artist, etc), and you'll see that it doesn't match.
As for the streaming questions, it goes like this:
- I enable match on my desktop pc. It does it's thing.
- I enable match on my iPhone. NOTHING CHANGES ON MY IPHONE that was the same as my iTunes on my PC was before I enabled match. No songs get deleted, etc. If you sync regularly, it's as if nothing happens.
- You will notice a few things though:
First, if your PC had songs on it that your iPhone didn't, those songs will appear on your iphone with a little cloud next to them. Click the cloud and it downloads the song (matched or uploaded, it doesn't matter). Click the actual song title and it'll play the song "like" it's streaming, but it is still downloading it. IE: NO PURE STREAMING OPTION.
Let's say there was a 128k song you had on both your iPhone and PC. On your PC, you've enabled match and decide to delete this song and redownload the 256k version. THIS DOES NOTHING TO THE 128k VERSION ON YOUR IPHONE. If you want that 128k version on your iPhone to become the 256k version, it doesn't happen automatically, you'll have to do the identical process of deleting it from your iPhone, and redownloading it.
It seems like Itunes Match makes sure your songs all "match" across devices, but it could care less about which bit-rate version they are.
The only way I can think of truly matching your iPhone with your PC/Mac (as in, get those 256k versions on your iPhone without taking a year doing it) would be to turn off Match on your iPhone, sync with your proper list of songs on your PC/Mac, and then turn back on Match on your iPhone.
Any thoughts on that?