h264-live-player | A live h264 player for the browser ( ideal for raspberrypi

I'm reading an H.264 stream from a camera on a raspberry pi. I'm trying to pass this to Broadway via websockets to render in a web page.

The stream contains NAL units, and I'm chunking it on the [0,0,0,1] start prefix code, to send and then decode NAL units individually. I think that's working fine, but Broadway can't decode the result I end up with.

Digging into the parsing code I've based this on though, it seems to be expecting the 5th byte (straight after the start prefix code) to be either:

• 0x65 - an I frame
• 0x41 - a P frame
• 0x67 - an SPS frame
• 0x68 - a PPS frame

I've seen a lot of mention of these elsewhere too. All the units I have coming through though seem to start with (in order):

• 0x27 0x64 (1st unit)
• 0x28 0xEE (2nd unit)
• 0x25 0x88 (3rd unit, then intermittently later on)
• 0x21 0x9A (every single other unit in the stream)

What do these headers mean in an H.264 stream? Do they suggest something about what I need to do to match Broadway's expectations?

(If the full code would be useful to understand this better, see https://github.com/pimterry/pi-cam/tree/d801de9b)