617: Mp4

: These "Premium" or high-bitrate itags (like 616 and 617) are part of YouTube's efforts to provide enhanced quality for certain viewers or devices [26, 30].

In the context of YouTube's internal format identifiers (itags), is a specific MP4 video format code. Format Details Video Format : MP4 (H.264/AVC) [26]. 617 mp4

: Typically a "video-only" stream, meaning it must be combined (muxed) with a separate audio stream (like itag 140 or 251) for full playback [28]. Usage and Issues : These "Premium" or high-bitrate itags (like 616