Facebook videos playing in low quality I recently purchased a new phone that uses android 8.0, whilst viewing a video on Facebook the thumbnail is clear and then when the video starts the video becomes very pixelated. The issue only occurs when using Facebook mobile app, the Facebook website streaming is in full hd. 

I have tried setting my default preferences to hd when available but doesn't make a difference. My WiFi speed is not an issue neither. 

I am starting to think that this could be a app/android settings issue?

Thanks!
I think this could be due to 2 reasons:


The videos you are playing are not available in a better quality. Or;
Facebook thinks that your connection is slower and hence reduces the playback quality. 


You can see that it is not the 2nd by manually choosing a playback quality:

When you play a video and tap on the player, a gear icon should appear. And here you'll get the quality options.
Consider changing it from Automatic to one of the available qualities and see if that improves the playback.