There is some documentation at:
http://sdkdocs.roku.com/display/sdkdoc/ifVideoPlayer#ifVideoPlayer-SetMaxVideoDecodeResolutionwidtha...In simple terms it is the maximum video resolution that you expect to use for your channel. This would only apply to those devices that use OpenGL, since the 2D API texture memory is a shared resource with Video Decode Memory. So for a device that uses OpenGL, if you know that your maximum video resolution will be 1280 x 720 you must set the value in SetMaxVideoDecodeResolution to at least 1280 x 720. If you do not, the movie will load but kind of hangs right there. With non-OpenGl this does not apply. I'm speaking about the current line of devices. So if you do not expect to use anything more than 720 x 480 then its best to set this value so the resources can be allocated to the 2D API
As far as what r2d2_bitmaps displays is device specific.
Basically it is the amount of memory that you have available to load your bitmaps. Once exceeded you will get an invalid bitmap handle upon creation
My Channels: 2D API Framework Presentation: https://owner.roku.com/add/2M9LCVC
Updated: 11-11-2015 - Completed Keyboard interface
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