audiobook chipmunk problem with iPod

chickenjames · 03-27-2015, 06:06 PM

hey all

I have been suffering from a _very_ annoying problem when using my iPod classic connected through USB in my F32 428i GC.

I listen to a lot of audiobooks and some tracks don't play properly when you switch off the engine then resume playing - they are played very fast, giving a chipmunk effect. The only way to recover is to play a 'good' track.

This annoyed me for ages! It turns out that there's a bug in the BMW headunit when you're playing files from a USB device (as opposed to streaming over Bluetooth). The resume doesn't work properly unless the sample rate is 44.1KHz. If your sample rate is 22KHz (quite popular with mono audiobooks) then you get the problem. I haven't tested with anything at 48kHz but I imagine that if you do, then the track will get played a little slow.
This is definitely a headend bug but there's a fairly easy workaround in iTunes - recode the track to have a sample rate of 44.1KHz. I haven't yet found any tracks where this doesn't work.
It makes no difference I think, whether the offending track is mono or stereo.

hope this helps

Fronzdan · 03-27-2015, 07:21 PM

Good tip. This is the kind of thing I'd spend hours on, trying to figure out.

My latest is that my Classic doesn't seem to be showing artwork. Now I'm not positive the songs I've been listening to have artwork assigned...but I think they do.

chickenjames · 03-28-2015, 04:52 AM

trust me, I spent hours figuring this out!

03-27-2015, 06:06 PM	#1
chickenjames Enlisted Member 5 Rep 35 Posts Drives: 428i GC Join Date: May 2014 Location: Marlborough iTrader: (0)	audiobook chipmunk problem with iPod - fixed! hey all I have been suffering from a _very_ annoying problem when using my iPod classic connected through USB in my F32 428i GC. I listen to a lot of audiobooks and some tracks don't play properly when you switch off the engine then resume playing - they are played very fast, giving a chipmunk effect. The only way to recover is to play a 'good' track. This annoyed me for ages! It turns out that there's a bug in the BMW headunit when you're playing files from a USB device (as opposed to streaming over Bluetooth). The resume doesn't work properly unless the sample rate is 44.1KHz. If your sample rate is 22KHz (quite popular with mono audiobooks) then you get the problem. I haven't tested with anything at 48kHz but I imagine that if you do, then the track will get played a little slow. This is definitely a headend bug but there's a fairly easy workaround in iTunes - recode the track to have a sample rate of 44.1KHz. I haven't yet found any tracks where this doesn't work. It makes no difference I think, whether the offending track is mono or stereo. hope this helps
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03-27-2015, 07:21 PM	#2
Fronzdan Lieutenant Colonel 304 Rep 1,739 Posts Drives: '24 M240 xDrive Join Date: Mar 2014 Location: MA iTrader: (0)	Good tip. This is the kind of thing I'd spend hours on, trying to figure out. My latest is that my Classic doesn't seem to be showing artwork. Now I'm not positive the songs I've been listening to have artwork assigned...but I think they do.
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03-28-2015, 04:52 AM	#3
chickenjames Enlisted Member 5 Rep 35 Posts Drives: 428i GC Join Date: May 2014 Location: Marlborough iTrader: (0)	trust me, I spent hours figuring this out!
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