2011/7/19 Maksym Veremeyenko <[email protected]>:
> Hi,
>
> in my previous message about audio buffer overflow i did not noticed about
> possible reason.
>
> IMHO one of reasons is too high priority of melted. That cause decklink
> callback delayed if avformat producer has higher activity.

The priority boosting is kind of a legacy thing when we were using
BlueFish444 for SDI output and letting threads inherit scheduling
priority and class - basically trying to make the process and all of
its threads the same higher priority.

> To avoid it i prepared patch (*0001-change-priority-on-demand.patch*) that
> enable maximum priority if it required by argument from command line, also
> that makes possible to setup priority higher then default.
>
> After changing priority to default value no overrun happens.

good, but I wonder if we should completely drop the priority-setting
in melted. For some time now, I have had a priority property in
mlt_consumer (now documenting it). Then, consumers that create their
own output threads might use this or their own property. I do not
really think the network I/O and MVCP command processing ever needs a
high priority - certainly not higher than the SDI output.

> So next step was to increase a decklink callback thread priority over other
> threads in MLT - *0005-rise-DriverNotificationThreadFunction-priority.patch*
> - that could give additional benefits on decklink hardware control timings.

Do you think this should this be controlled by a property? For example,
if (mlt_property_get_int(properties, "priority") < -20)

-- 
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