[wordofx]

> If your HTTP server provides and supports the appropriate headers and you’re serving supported file types, then it absolutely is true.

No. When you play a file in the browser with a video tag. It requests the file. It doesn’t ask for a range. It does use the range if you seek it, or you write the JavaScript to fetch based on a range. That’s why if you press play and pause it buffers the whole video. Only if you write the code yourself can you partially buffer a while like YouTube does.

[bmacho]

Nah, it uses complex video specific logic and http range requests as protocol. (At least the normal browsers and servers. You can roll your own dumb client/server of course.)

> That’s why if you press play and pause it buffers the whole video.

Browsers don't do that.

[jonathanlydall]

Obviously it doesn’t initially ask for a range if it starts from the beginning of the video, but it starts playing video immediately without requiring the whole file to download, when you seek it cancels the current request and then does a range request. At no point does it “have” to cache the entire file.

I suppose if you watch it from start to finish without seeking it might cache the entire file, but it may alternatively keep a limited amount cached of the video and if you go back to an earlier time it may need to re-request that part.

Your confidence seems very high on something which more than one person has corrected you on now, perhaps you need to reassess the current state of video serving, keeping in mind it does require HTTP servers to allow range requests.