Overlaying on video

Ben Rubinstein benr_mc at cogapp.com
Sun Mar 26 18:54:42 EDT 2017

I'm trying to overlay some graphics on a video, and hit a couple of problems.

The first, which drove me somewhat mad until I found an out, was that the 
video was always displayed on top of other LC elements - graphics, fields. 
This is using a player object; I found that the controller would be rendered 
correctly layered among other objects, and indeed would obey blending levels; 
and occasionally in tool mode the video frame would also; but once I switched 
back to browse mode and played the video, it invariably displayed on top of 
everything else, at 100% opacity. Toggling the "buffer" property did not 
appear to make a difference.

Eventually I discovered by accident that this only applies to some videos. For 
now, I got the job I needed to do done by rendering the original .mp4 into a 
.mov with QuicktimePlayer's default settings; I haven't had time to establish 
what the crucial factors are. Is this known/documented anywhere?

The second problem - which I also found frustrating because I'm sure I've done 
something similar before without this arising - was in triggering the updates 
to my overlay graphics. I thought that I could have a timer sending a regular 
message to my code which would check the time of the movie, and adjust 
graphics appropriately. The code worked but I only saw an update twice; when 
the movie started, and when it stopped. As far as I could tell this wasn't an 
issue about the screen not updating; but that the message genuinely wasn't 
sent while the movie was playing. Again, is this a known issue? Or do others 
think this should work, and I was just doing something wrong?



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