399 Mp4 -

If you want to manually select this format to ensure you get the AV1 1080p version, you would use a command similar to this in your terminal: yt-dlp -f 399+140 [VIDEO_URL] Use code with caution. Copied to clipboard

AV1 ( av01 ), which is a modern, royalty-free codec designed for better compression and quality compared to older formats. 399 mp4

According to technical discussions on Reddit and GitHub , 399 is often preferred because: If you want to manually select this format

It is the most modern codec YouTube offers for 1080p, allowing for higher frame rates that older caps (like 30fps) don't support. which is a modern