I think there is a big variety of options can be used. Depends on what final video is for, what quality of both audio and video is required. And of course the availability of equipment and budget is important. I mean, one thing, if it’s just for home collection memories, kinda overlaid performance of guitartrack and self video recording synchronized with backingtrack. In this case, as you mentioned, the live performance option with simultaneous recording with a good smart phone is better. BTW for posting in FB or Insta it should be good enough also.
Although, if it’s kinda promo reel or commercial application record such as youtube, web-site, vimeo etc, I think the mentioned separate audio/guitartrack and video recording is better. Preferably to do it in audio or video production studio, if the budget worth it’s expected return. Otherwise, as you mentioned, with DAW or recording soft. The separate recording advantage is also that you have the universal set of tracks and video footage for different purposes. So you can make a lot of things with it’s combining. I mean to make either voiceover to your live-performance video, or to pre-recorded footage, or to stock-video or even to animated video if you wish to sync. One-time record for a life-time use 😃
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