: Some users have reported significantly slower download speeds when requesting the 617 format compared to other high-definition streams like itag 399 [28].
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 : Some users have reported significantly slower download