i have a problem with my YouTube iFrame and FireTV streaming app. The stream resolution will always stick to large. The streaming options are set correctly (vq=highres, suggested video quality = highres etc.).
I tried other Youtube steam URL's and it seems like the 4k FireTV won't display 4k streams (vp9 codec) better than large (960x540). However a lower quality stream (with avc codec) provides 1080p resolution with my test setup. I tried a packaged Android App and an Amazon Web App with the same result.
If i embed the iFrame part in other apps or webpages the stream is always set to the correct quality.
I know Android Apps for FireTV's get low screen resolution because of the FireTV Stick but thats no problem for 1080p streams. I tried that already.
This got to be a problem in the firefox webview. Does anyone got an advice for me how to get 4k or at least better resolution?