When you embed Youtube videos into websites they are defaulted with Standard Quality.
If you want to embed a Youtube video with High Quality use the following website. Embed Code Generator for High Quality YouTube Videos
Only paste in the ending ID code of the YouTube URL that appears in the address bar.
So if it looks like this:
then you should only paste YpQ-R8ueK88
in the box and ignore everything before and including the v= and ignore everything after and including any & and make sure there is no space at the end.
Then click 'Create Code' and copy & paste the resulting embed code in a script box in Tiny Portal.
Hope this helps someone.