Last week we reported problems with audio dropouts when attempting to play back files encoded in the new, larger file-size "lossless" format offered in iTunes 4.5.
The iPod and iPod mini both sport a 32MB RAM buffer. When a track commences, the iPod caches the audio (up to 25 minutes) in the buffer, allowing for uninterrupted play if the hard drive is disrupted, as well as increasing battery life by accessing the hard disk less frequently.
If files exceed this 32MB buffer, the iPod has to re-access its hard drive, in some cases causing the audio dropout.
Grant Jacobson writes "I originally purchased an Ipod because of a little-known capability it has. It can playback aiff and wav files. These are direct digital copies of the original and are not compressed in any way. This made for the best sound quality I had heard from a portable device. I was a happy camper! However, as I started following the upgrade trail, I began uncovering a nasty bug that I dutifully reported to Apple. I upgraded from 1.2.1 to 1.2.6 and that was a good upgrade - added features and better battery life. I then upgraded to 1.3.0 and the problem surfaced. After approximately 2:20 minutes of playback the sound would cut out for about a second. It was absolutely repeatable. Second level support was very courteous and professional and committed to taking the information to engineering. The memory buffer was not being refilled in time to prevent the dropout. "
Possible solution One MacFixIt writes "To get over this I always ensure that any mp3 or aiff over 20Mb is segmented into smaller files so that they always fit into the buffer. "
Specific to iPod firmware 2.2? For some users, the sound dropout problem is only occurring after the iPod firmware 2.2 update:
Pawel Soltysinski writes "I can confirm similar problem with iPod (firmware 2.2) - I have converted some long audiobooks into AAC into pieces about 7 hours long (a piece). Dropouts are quite often - just stops playing or goes to the beginning of the next audio file.
"I had those files with iPod firmware 2.1 and there were no such troubles. To me it is definitely file-length problem - long files are causing problems to the new iPod's firmware."
Remote control issues We're seeking confirmation for an issue where iPod remote control problems surface after the iPod 2.2 updater. MacFixit reader Jason writes "I have a 20 GB iPod and since updating it with the latest update, it is recognized fine by my mac and everything seemed to work okay until I started playing sound files. Anytime I use the remote to rewind or fast forward, the music being played becomes garbled for a few seconds then the iPod shuts off. Once I turn it back on, everything works fine again, until I use the remote. The volume and pause/play buttons on the remote work fine. Rewinding and fast forwarding using the scroll wheel still works fine as well. There just seems to be a problem with the remote."