Re: iOS app performance degraded on iOS 4.3?
Re: iOS app performance degraded on iOS 4.3?
- Subject: Re: iOS app performance degraded on iOS 4.3?
- From: tahome izwah <email@hidden>
- Date: Fri, 25 Mar 2011 10:02:36 +0100
Doing hardcore DSP work inside the RIO callback is never a good idea,
especially if you're using calls that can block, such as file i/o (not
sure if this is the case in your application) or ObjC calls. It's
usually better to set up a separate worker thread that does the DSP
work and use the callback to just copy data.
I frequently use the "DiracRealtimeExampleLE" time stretch example
project as a template for this as it works great as a starting point
for all sorts of DSP processing. You can get it from
http://dirac.dspdimension.com about mid-page (not the DiracLE SDK, the
additonal realtime sample project). Just remove the Dirac calls and
add your own...
HTH
--th
2011/3/24 Doug McCoy <email@hidden>:
> I have an iOS app that I have been working on for several months and I have
> got it to the fine tuning stage almost ready for release. It is a realtime
> audio app that uses the RemoteIO audio unit for realtime I/O. The app has
> realtime DSP between the input and the output so there is a bit of work
> being done in the callback.
> The thing is, it has been working well on all devices 3gS and newer. That
> is, until iOS 4.3. On the 3gS device with iOS 4.3 there is terrible audio
> distortion when the app is doing the peak work. The i/o is fine when the cpu
> load is less, but when the app is working hard, distortion occurs. This
> makes me think it is related to cpu load. Missing the callback deadline and
> such.
> Using the same build, same app, same everything on a 3gS device running iOS
> 4.1, the app works perfectly, as it has in all recent testing before the
> upgrade to iOS 4.3. So the only difference is the iOS version.
> Is there any known issue with audio performance on older devices with iOS
> 4.3?
>
> Please help.
> Doug
>
>
>
>
> ---
> Check out my new iPhone app, FlipTalk. Once featured on the iTunes App Store
> "What's Hot" list!
> http://fliptalkapp.com
> http://itunes.com/apps/FlipTalk/
> http://tinyurl.com/FlipTalkYoutube
>
>
>
>
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