Sometimes it can be quite difficult to play well while being filmed. There are three things to think about: being recorded, looking OK and actually playing in tune and without mistakes. To make life easier, on my guitar part I recorded my self with a decent mic (audio) only. Then I filmed myself playing along to the audio (using discreet headphones). The video and audio can then be aligned and the filmed audio disregarded. I found it took a bit of pressure away from the filming as the odd fluffed note wouldn't be heard and it's easier then to look relaxed.