Minimize Excessive Player Processor Use?

[Josh Mellicker]

On Jan 25, 2010, at 5:28 PM, Scott Rossi wrote:

> Recently, Josh Mellicker wrote:
> 
>> Incidentally, the docs on qtIdleRate have an error, they say:
>> 
>> 
>> "A higher idle rate will result in smoother playback but will also require
>> more cpu time."
>> 
>> but they should say:
>> 
>> "A LOWER idle rate will result in smoother playback but will also require more
>> cpu time."
> 
> I wouldn't say the docs are wrong, just ambiguous.  "High" could refer to
> the duration of the idle interval (a high number), or could refer to the
> frequency of updates (high frequency).


That's what I assumed, but since the docs say both:

So they say "a higher idle rate... require(s) more CPU time"

and:

"Increasing the qtIdleRate... decreases the amount of CPU time"

you need to make the assumption that the words "higher" and "increasing" mean opposite things, and you have a 50% chance of getting that right :-)


> 
> 
>> Lowering the qtIdleRate from 20 (30% CPU) to 1 (50% CPU) improved playback
>> performance dramatically for me.
> 
> I don't see how setting the qtIdleRate to 1 leads to 50% CPU.

I am judging by the Processes tab in the Task Manager of a POS Vista laptop... I'm sure there's a better way to gauge CPU usage on Vista, can you recommend a utility?

Getting smooth Quicktime video playback in Revolution, especially on Vista, has been a problem for us, but lowering the qtIdleRate to 1 from the default (the 4.0 docs say 50 is default, the 4.5 docs say 20) improved playback performance dramatically.


>  Doing this
> sets the delay between player updates to 1 millisecond.  Over here, doing so
> spikes CPU usage to 100%, which is in keeping with any other message sending
> that occurs with a frequency less than 1 second (ie a send loop like send
> "updateMe" to this card in 1 millisec).  Are you also doing something with
> the idleRate? (not qtIdleRate)


No, but I think we'll experiment with that next. It would be GREAT to get a little clarification from the RunRev folks about how the qtIdleRate and idleRate work together, and also recommend specific strategies to get the best video playback performance with the lowest CPU usage.


> 
> 
>> I wonder what the qtIdleRate represents - maybe a "tick" (1/60 sec)?
> 
> The docs say the qtIdleRate is the time in milliseconds between one update
> of a player and the next.

Aha!

> 
> Regards,
> 
> Scott Rossi
> Creative Director
> Tactile Media, UX Design
> 
> 
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