: It is essentially the MP4 twin of format 356 , which contains the same video stream but in a WebM container.
If you are seeing "616.mp4" in your downloads or logs, it means you (or your downloader) have accessed the higher-quality premium version of a video. This version typically offers:
Are you having this specific format, or were you looking for a technical breakdown of its bitrate and codec?
: Reduced compression artifacts, especially in high-motion scenes.
: This format is usually only visible and downloadable via tools like yt-dlp if you provide a cookies file from an account with an active Premium subscription. Why Does It Matter?