Apple Thoughts: Sync Problem With iTunes 9.1.1

"iTunes 9.1 brought a feature to all iPods that had previously only existed for the Shuffle: the ability to sync lower bitrate, 128 kbps AAC versions of songs."

And the article continues: "With only a modest reduction in sound quality, enabling this feature saved nearly 2 GB of space on my 16 GB iPhone 3G. After enabling it, the feature works by re-encoding songs on the fly to the lower bitrate the first time you sync your iPod. This will likely be followed by a very lengthy first sync as hundreds or even thousands of songs are downsampled to 128 kbps AAC, but all subsequent syncs are supposed to skip this step altogether unless you make major changes to your music library."

Ah but what he has found is that the sync operation every time after was extremely long as it re-encoded music that had previously been encoded. Basically it was doing the process all over again. So if you are experiencing this, check your version and if you have 9.1.1, then download iTunes and reinstall and it should go away. The new build hasn't been pushed out yet so it isn't in Software Update. This is only happening if you have enabled the option to convert higher bitrate songs to 128 kbps AAC on your iPod or iPhone. If you didn't enable it then you won't experience the problem.