399 Mp4 (2026)

Usually wrapped in an MP4 container, though it is technically "video-only" and must be merged with an audio stream (like itag 140) to create a playable video file. How to use it in yt-dlp

It is the most modern codec YouTube offers for 1080p, allowing for higher frame rates that older caps (like 30fps) don't support. 399 mp4

Format is a video-only stream used by YouTube for high-quality content. Key characteristics include: Resolution: 1080p (Full HD). Usually wrapped in an MP4 container, though it