important iTunes install info

[zootbobbalu]

Dont freak out if iTunes hogs your CPU and your music starts to cut out unpredictably.

I just installed iTunes 3. After I changed some of the effects preferences, iTunes started to cut out from time to time when I would change applications or when I would open up web pages. This was really annoying.

After watching "top" from the terminal and observing how many CPU cycles iTunes was taking up, I noticed that iTunes was taking up 85% of my 450MHz G4!!!!!

Turns out that the "sound check" effects setting is the cause. This effect really taxes your CPU. If you don't have a Dual 1GHz G4 Tower and you need to get work done on your mac, you can stop iTunes from scanning your entire music library by clicking on the x to the right of the status bar.

If you have some time to kill, then let iTunes do its thing after adding the "sound check" effect. iTunes is taxing your CPU because it is scanning every song in your music library. I don't know how long this takes, but I have a large music library (40GB) and iTunes was still scannning after 15 minutes of waiting.

[ElDiabloConCaca]

I encountered a weird problem where, upon launching VirtualPC and starting my Windows 2000 Pro installation, iTunes stopped playing completely. Actually, that's not exactly accurate. The volume just stopped. The song was still playing away -- I could tell by looking at the status bar in iTunes and see that the seconds were still counting away. Changing the volume up or down, even in the slightest, using the keyboard volume keys restored the sound.

This is completely repeatable with VirtualPC, and semi-repeatable with other processor-intensive applications.

[goynang]

Same here!

I wondered what was going on - I had indeed clicked 'check sound levels' so now all is explained.

I've only got a few hundred meg of mp3's so didn't take too long.

[zootbobbalu]

If anyone else is having this slowdown, can you let me know how long iTunes took to scan all of your music library (library size would be good to know too).

[Captain Code]

Are you sure that it's scanning every song in your playlist?

I thought all it would do is adjust the volume as the song is being played so that all the songs play at the same volume level.

[zootbobbalu]

I'm not sure, but why would iTunes need 85% of my CPU to adjust levels?

Other people have reported that iTunes stops hogging CPU cycles after running in "sound check" effects mode for a period of time.

If I have to except 85% CPU overhead just to listen to music in "sound check" effects mode I'm not going to use this effect.

I'm going to run iTunes while I sleep tonight and I'll post what happens.

Oh, to answer your question, I think iTunes is checking every song so it can create a record of the levels of every song, this way iTunes wont have to recheck songs over and over again.

[Snowball]

like what zoot said, yes, iTunes is remembering the levels of each song and adjusting their playback volume accordingly. Of course this library also goes to the iPod. I wonder if it the library is song-specific, i.e. each MP3 gets a little tag added that says how much to change volume, or if it is just one big database stored somewhere on the comp? I would guess the 2nd option.

I think the better way to approach the Sound Check is to bring up a dialog box on 1st iTunes launch like previous ones that says "would you like to enable sound check? this will take some time to set up" or something like that.

[Captain Code]

I just tried out this sound check thing, and it appears that you are correct about it scanning all of your files.

It actually shows that it's doing it in the play window(where it shows the song title, time remaining, progress, etc), displaying the song that it's scanning.

However, you can stop it easily by clicking on the little X button that appears in the play window.

FYI, scanning 166 songs took less than 2 mins on a G4 400.