Supports up to 60fps (High Frame Rate/HFR), offering smoother playback for action-heavy content.
Format is a video-only stream used by YouTube for high-quality content. Key characteristics include: Resolution: 1080p (Full HD). 399 mp4
According to technical discussions on Reddit and GitHub , 399 is often preferred because: Supports up to 60fps (High Frame Rate/HFR), offering
It provides better visual quality at a lower bitrate than the older H.264 (AVC) codec. 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