Root [International] Kit-Kat video problem

Hi All,

I installed CyanogenMOD last week, everything was fine for a couple of hours, then every video I looked at online had sound but no video.
I assumed it was because of something I'd added in, like Go Launcher instead of Trebuchet for instance (and systemUI kept crashing), so I re-flashed the ROM.
Same again, video works fine for a couple of hours & then I get sound but no video.

I assumed then that it must be a cyanogenmod problem, so today I switched over to OmniROM - And exactly the same thing happens.

OK, so, it looks like being a Flash player issue, Android no longer supported by Adobe if I'm reading the forums correctly.
If this is the case, teams are putting out ROMs that can't play a simple YouTube video? Don't buy that really.

So, YouTube's owned by Google, as is Android, but I can't play video on a clean android phone because I don't have Flash?
I don't buy it.

Does anyone have any idea why it works for a bit & then breaks?
Can anyone tell me how to get video working again please?

Many thanks.