Well there are 2 things to consider when you are choosing between HD and 480P. First thing is what kind of videos are you making? If you are filming vlogs, or gaming videos then yes you MUST use 1080p or even 4k if possible. But in special cases like educations slide shows with you talking in the background, the highest resolution needed will only be the resolution of your highest quality pictures. So for example if the best photo's you have are only 720P or even 480P then go with that. Lastly you must consider the power of your PC. If you have an older computer then the rendering required to make say a 20 minute video in full 1080 P will take HOURS! So if this is the case you will either have to use lower resolution or plan accordingly for the long rendering times (i would recommend the latter)