user12801: I downloaded my own video from YouTube, it is 4k and is an av01 file type. Quicktime can't play it, VLC does.
When I try to import the file into Premiere it gives me this error.

Any solutions or do I just need to convert it using Handbrake or something? I don't want to lose quality etc.

user29988: Whenever you get such an error it does indeed mean the file is not supported and you cannot edit it without transcoding it to another format first using another tool.
Choose a compatible format and make sure the bitrate is set high enough to avoid noticeable compression artefacts. If possible, set the tool to copy the audio track because it probably doesn't need transcoding.

12801: <p>I downloaded my own video from YouTube, it is 4k and is an av01 file type. Quicktime can't play it, VLC does.</p>
<p>When I try to import the file into Premiere it gives me this error.</p>
<p><a href="https://i.stack.imgur.com/656aJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/656aJ.png" alt="enter image description here" /></a></p>
<p>Any solutions or do I just need to convert it using Handbrake or something? I don't want to lose quality etc.</p>
 29988: <p>Whenever you get such an error it does indeed mean the file is not supported and you cannot edit it without transcoding it to another format first using another tool.</p>
<p>Choose a compatible format and make sure the bitrate is set high enough to avoid noticeable compression artefacts. If possible, set the tool to copy the audio track because it probably doesn't need transcoding.</p>
