Quick Summary: If you are seeing significant Dropped Frame rates in your cockpit video statistics try disabling the use of Hardware acceleration in Chrome advanced settings.
The weekend is here and I’ve had time to dig in further–
It seems the statistics reported in the cockpit display relate to the on-screen (Chrome browser) display of the ROV’s real-time images. Meaning-- number of packets received by Chrome and number dropped by Chrome.
I’m deducing this (hopefully correctly) by noticing that the statistics on dropped packets are markedly improved when I navigate away from the cockpit (though it is still active in the background but not refreshing the screen at all-- then return to it. Dropped Frame rate does not increment.
I checked my Rev of Chrome and I’m up to date.
I checked my system and have all current (Mac) OS and Drivers (including Graphics accelerator card).
I note that I have a responsibly powerful machine-- 2.6GHz Intel Core 5 with 16 Gigs memory and and Intel Iris 1536 Graphics accelerator card, 500Gig Solid State Drive.
As part of testing I changed the frame rates and the resolution and found no improvements in the dropped frame rate-- always hovering around 30-50%
I next investigated ways to try and force the system to use the Graphics Accelerator Card. There is a Chrome Setting: Advanced Settings: System: Use Hardware Acceleration when available-- but this was already selected.
Looking at the CPU monitor I found a process called: VTDecoderXPCService which was consuming most of my CPU cycles in in conjunction with Chrome and Chrome Helper.
A google search revealed that the VTDecoderXPCService is a Sandboxing service in OSX. Though there aren’t many (any) high level descriptions about it I did find this helpful article:
I also found a reference in a help thread re: Chrome Dropped Frames that suggested disabling the “Use hardware acceleration when available” feature-- seems counter intuitive but worth trying. (Requires Chrome reboot)
WOW-- what a difference that made. Dropped frames dropped to around 1-5%.
I also noticed VTDecoderXPCService left the system monitor or had such a low CPU % that it left the screen.
I can only assume the VTDecoderXPCService was invoked by Chrome as part of Hardware Acceleration but I am not certain of that.
My CPU cycles significantly increased as a result of the hardware acceleration change-- but I think it’ll be OK. Not sure how it will impact battery life etc.