[vlc-devel] Filter not ready to be set after being created, how to synchronise?

[jboileau]

Hi,

If we create a filter and try to access it immediately it will not
work. For example using var_SetString to create a marquee and
immediately after that set its text or other parameters using a second
call will yield incorrect results. If after creating the filter a
sleep of 25ms is introduced before setting the marquee everything
works fine. Of course a sleep is not what I want to use. So my
question is: how do a synchronise/detect that my filter is ready to be
access? How do I wait until it is ready? This seems to be true for all
the filter I have tried.

This probably does not cause too much problem in VLC because these
changes are done trough the UI and the user will always introduce a
delay between enabling a filter and playing with its settings. The
adjust filter is good example where it works fine through the UI. But
in my case, I enable and play with a filter programatically where
there is no delay.

Although for VLC it is not entirely true that there is no problem. The
last build I checked, the add text option in the extended panel did
exhibit some of the problems I am having. If you select Add text and
type text it appears over the video as expected. Unchecking the Add
text check box does not remove the text on the screen. If you check it
again and type text it will be on top of what is already there.

-- 
Jacques Boileau