Looping sound not seamless on iDevice

[Spoondog]

Hi,

I'm having some problems with looping sounds on iOS. It's a top-down racing game and the player has a basic looping engine sound that plays via an audiocomponent. The sound is 0.46s in length and loops via an audio cue with a default looping node.

It all works fine in the mobile previewer and editor, but on the device (tried ipad 3 and iphone 4s) it cuts between loops.

I've searched around tried stuff:

• Made *all* sounds, including that one, are 22050Hz, Mono, 16bit WAV
• Made sure the package is loaded at startup
• Tried in release and shipping
• Tried various sound classes

Suspected it might have been frame spikes, even though the game runs at a constant 60FPS on the device, so I tried playing with smoothed framerate on/off, with different max framerates... no difference.

It definitely seems related to the sound loop itself - the hitching occurs in time with the loop (if I put pitch down to 0.1, the hitch occurs less frequently, if I put it up to 2.0, it occurs rapidly).

Anyone else got any ideas? I'm fairly inexperienced with audio, so there might be some other precautions I could take when exporting the sound?

[KnightsOfMalta]

Which UDK version are you using?.. The sound on IOS has had many issues in past UDK versions, is it clicking/popping every time it loops round? If so it might be the version your using, I think they fixed it in the latest one, but it still could be broken.

[Spoondog]

Hmm yea I'm on the November 12 one, I do remember waiting several months for them to fix a sound issue before I merged to that one, but I think that was an issue with sound not playing at all.

I was planning on merging to July at some stage... if I don't find any other solution I will try that, thanks.

[WilliamDocherty]

HI

I'm using the July 2013 UDK and a lot of looping sounds - I've not noticed any problems with them.
I use 22050Hz, Mono, 16 bit for all my samples as well
You didn't mention it above - but have you ticked the "looping sound" box under "compression" in the sound cue for your sample?
This is required to "fix up" the sample to work correctly.

Cheers
William

[Spoondog]

The "looping" box is ticked by default for me.

I have a sneaky suspicion that right after I upgrade to July, they're gonna release a new one But oh well, it shouldn't be very painful anyway.

[Spoondog]

Confirmed going to July fixed the sound.