CODEWITHSUNDEEP
iosvideoffmpegvideo-streamingmp4
Eddie Xie
Eddie Xie

Reputation: 925

mp4 pseudo-streaming implementation server & iOS side

I'm trying to learn how to do pseudo streaming for MP4 files. I can't think of a good way to do it, but I just found a great example app has similar implementation (except I don't understand how it does it yet)

Here's the scenario:

Alice can send a video to Bob in the app

Bob can open it immediately and see Alice's video, from beginning, while Alice is still recording it

Also, Bob can choose to view the video later after Alice finished recording. But Bob should be able to view the video instantly without waiting too much time, even when the whole size of the video is large.

Thus, my hunch is, it's using some sort of pseudo streaming for mp4.

Here's the screenshots of the requests Alice's phone makes while using the example app:

enter image description here

The screenshot suggests, the example app is making an array of PATCH requests to their server, every 0.x seconds. And finally, the very last request will make a PATCH to update the moov information for this MP4.

Thus my question is, how is this implemented (any educated guess will be welcomed)? Or is there any sort of existing protocol/iOS encoder that I didn't know is doing this already?

Thanks a lot!

Upvotes: 0

Views: 277

Answers (1)

Mick
Mick

Reputation: 25471

Reading the text of your question rather than the title, I think there are a number of likely steps:

  • Alice is recording video
  • She is ending the video to a streaming server
  • Alice notifies Bob that the stream is available and sends the URL on the streaming server that Bob can access to retrieve the stream
  • Bob's video client requests the stream, using range request to download it chunk by chunk

Have a server in the middle like this is a typical approach for any stream which may have more than one client watching it.

More sophisticated streaming servers may also support delivery the stream in different bit rates and even encoded with different codecs for maximum device reach.

There are commercial (e.g. https://www.wowza.com) and open source streaming servers (e.g. https://gstreamer.freedesktop.org) you can look at to get more info on streaming servers and to see some examples.

Upvotes: 1

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