Save H264 video to disk

[clone1018]

In order to support our future goals of providing users Video on Demand of previous streams, and Clips of particular sections of a live stream, we need to know how to save H264 to disk in a playable way.

My theory is that we could easily do this in a way similar to how Peer Snap works (and based on the architecture we come up with in #7). Since we'll be able to consume the RTP packets, and save them directly to disk.

Some Pion examples:

• https://github.com/pion/example-webrtc-applications/blob/master/save-to-webm/main.go
• https://github.com/pion/webrtc/blob/master/examples/save-to-disk/main.go
• https://github.com/pion/webrtc/blob/master/pkg/media/h264writer/h264writer.go

[nassah221]

I'm looking to pick this up. In the pion examples, the stream is written in ivf container for VP8. Do we want to use a container for our h264 streams (mpegtsmux?) or just write them as .h264 on disk?

Also, is it better to prioritise #7? IMO the thumbnailer code needs refactoring as we would need to generalize it to cover both cases of writing to disk and sending thumbnails.

[clone1018]

We'll have to implement a container for the eventual #12. I'm in agreement that #7 might be a good first start though to improve handling of these "outputs" that don't actually send their data anywhere.