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EnableFramerateCounter, Setting your Framerate correctly

[this was originally posted on, reposting as I am moving hosting sites]

Debug tool
I posted about EnableFramerateCounter before — it is a simple little debugging setting that you can use when trying to figure out:

  1. Which of these designs hurts my framerate more?
  2. If I add this module in, does it hurt my framerate?

To figure these out, you can:

  1. Set the plugin’s desired framerate at 1000 (silverlightObject.settings.MaxFrameRate OR Silverlight.CreateObjectEx({properties:{framerate:’framerate‘}}))
  2. Turn on the EnableFramerateCounter, which should show up in the status bar (IE/Firefox –> View –> Status Bar).

Desired Framerates
Make sure to reset the framerate to the suggested framerates for your app: Media apps @60fps or RIA/Control apps @20fps before launching your app to the public.
When trying to figure out the desired framerate of an animation or control-heavy app, use real people (not developers/designers) to gauge whether increasing the fps above 20fps makes sense. If you set your framerate at an unnecessarily high value, it will throttle the computer’s cycles — and could result in a jerkier effect than if you just had a lower framerate. So where 60fps might be slick and easy for your devbox, it could be a pain for your customer’s machine — so only use what you need.

The desired framerate of plugin hosting media is always 60fps — this gives the media pipeline the most number of ticks to figure out the optimal timing of presenting a frame. Silverlight will decode at the framerate of the encoded video (this usually is <32fps), and we present the frames in sync with the audio. To summarize roughly, if the platform doesn’t receive a tick in sync with the audio, then the platform will decode the frame, and then just throw it away. If you don’t understand this, just trust me and use framerate=60.

Technically, you could set the framerate dynamically — I haven’t tried this, but it might be a useful thing to try out if your app has both media and heavy controls/animations.

Debugging Settings

So here are the debugging settings that I use (not all at once, of course)


source: “xaml/Scene.xaml”,

parentElement: document.getElementById(“SilverlightControlHost”),

id: “SilverlightControl”,

properties: {

width: “500”, height: “500”,

isWindowless: false,

background: “FF000000”,

framerate: 10000 },

events: { onLoad:onLoadHandler} });

function onLoadHandler() {

agControl = document.getElementById(“SilverlightControl”);

/* To see the framerate displayed in the browser status bar */

agControl.settings.EnableFrameRateCounter = true;

/* To see the redraw regions*/

agControl.settings.EnableRedrawRegions= true;


I accidentally dumped the sugar canister into my tea, time to go home.

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