[smp1]

Sample 1 (DVD menu issue): shows blank screen (with gui menu overlay visible and audio). Disabling mmal makes it work. Disabling "adjust framerate" makes it work.Sample 2 (BD issue): blank screen with audio when trying to start the movie from within an on-disc menu. Disabling mmal makes it work. Also no issues when starting the movie from "Select playback item" instead of the on-disc menu. 

Actually, sample #2 also work fine when "Adjust display refresh rate" is disabled. Both samples suffer from the same issue - the blank screen occur after the refresh rate is changed.    

@popcornmix 
I tested this on more devices (including a smartphone). Raspberry Pi is the only device that gives me issues with some DVD/BD menus.
The issue is triggered by a refresh rate change ("Adjust display refresh rate" must be enabled). For example, those BDs that include 50Hz menus + 23.976Hz main movie (e.g. Sample 2) are affected.