Wednesday, 21 March 2007

Choosing the Frame Rate (W300i Time Profile)


So what is a good frame rate to choose for flash lite animations? Does a faster fps necessarily mean a faster, more optimal animation? It's a balance between smoothness of the animation vs the capacity of the cellphone to render. Let's take a look at one example:

Remember the Benchmark Animation Results? Well, all those tests were performed at 100fps. However, what happens if we choose different ones? What about 50, 120? Will the amount of time taken to render differ? I took out the w300i again for some testing.

This time, we have the same animation, but I've changed the frame rate. They increase as follows: 15,20,25,30,35,40,41,42,43,44,45,50,60,70,...120. Why did you I choose it this way? You can see from the graph below that there is a huge change in the rendering time between 40 and 45fps. The graph compares the theoretical (dark bars) vs. the actual time (light bars):


I was honestly really surprised at this! What's up with the huge change in render time? This data doesn't look too conclusive though. Let's run a couple more trials and calculate the time ratio. Recall, time ratio:

Time Ratio = Actual Time/Theoretical Time

After calculating this, let's look at the results:



Wow. There seems to be two extremely linear portions, showing a direct correlation between render time and frame rate: The higher frame rate, the RELATIVELY longer it takes to render. I'm NOT saying it takes longer it render, but the ratio is increased. The two linear portions are separated by a large dip, specifically 40-45 fps.

So from this graph, you can see that higher FPS doesn't necessarily mean a better relative render time. Moreover, the optimal FPS seems to lie around the 44-45 FPS range. This is quite surprising.

Remember: this is only for the W300i. I'd love to create some more time profiles for other model phones. If you'd like to contribute, please let me know! phirewerkz at gmail dot com.


3 comments:

Anonymous said...

Good article.
Thanks.
Can you test it for Nokia phones?

Phil said...

Yeah, I will try to get some to test.

Jorge Brivilati said...

It's great your post. I was studying exactly about this. would u like to talk more about this with me? Can we talk at msn? Please, add me: brivilati@gmail.com. I'm from brazil. sheers!