Apple

If you have limitless CPU cycles then it would be a weird interaction. It sounds very very much like the sort of behavior you get if there aren’t enough CPU cycles for everything, and the system is optimized for something other than what you’re trying to do.

I had serious trouble with an iOS app that needed to track finger movement and display video at the same time. It appears that iOS prioritizes tracking movement over anything else (at least, anything else that the app was doing). The video got really choppy etc. whenever you’d move your finger, and clear up immediately when you move your finger away. I found that the tracking loop was running as fast as it could, at the expense of all other computation. (The system is optimized for visual user interaction responsiveness.) I solved the problem by having my tracking routine do nothing and return immediately something like 4 times out of 5. Response to finger movement was slightly affected negatively, but video was substantially improved. I might have solved it by increasing the priority of the video processing thread, but that would have involved screwing around with Mach thread prioritization and hoping the app would still be approved by Apple for iTunes.

Steven J. Clark

VGo Communications

From: coreaudio-api-bounces+steven.clark=email@hidden [mailto:coreaudio-api-bounces+steven.clark=email@hidden] On Behalf Of Dave O'Neill
Sent: Thursday, February 19, 2015 3:21 PM
To: Ian Kemmish
Cc: email@hidden
Subject: Re: MusicPlayer with OpenGL interfere with UIGestureRecognizer

Really what I'm trying get to the bottom of, bug or no bug, is how can these three seemingly unrelated api conflict?

On Thursday, February 19, 2015, Ian Kemmish <email@hidden> wrote:

On 18 Feb 2015, at 17:00, "Dave O'Neill" <email@hidden> wrote:

> Once you see it being choppy press the play/stop button and see how
> the choppiness stops. Weirdest bug ever.

Unless the gesture recognition software you're using is documented as making guarantees about latency, then it's not a bug. It's life.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Ian Kemmish 18 Durham Close, Biggleswade, Beds SG18 8HZ
email@hidden Tel: +44 1767 601361 Mob: +44 7952 854387
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:

This email sent to email@hidden