[Live-devel] Library modifications

[Deanna Earley]

> > In this case, we’re receiving motion detection data from Vivotek IP
> > cameras.
> 
> How do these use RTP header extensions?  Is there a document somewhere
> that describes this?

Not that I can publish, sorry :|
It's just a block of data that's specific to Vivotek's cameras, but other cameras may structure the data differently.
It's opaque to liveMedia, and RFC 6185 (H.264 RTP profile) doesn’t explicitly allow or disallow use of the extension header in this way.

> > We have other cameras (AXIS) that use the H.264 SEI frames
> 
> OK, so these would just be carried via regular H.264/RTP packets - without
> requiring RTP header extensions.

Yes, we can handle these already without modifying liveMedia.

> > and some that use the ONVIF application data track.
> 
> And these are just RTP packets (albeit using a non-standard media type
> “VND.ONVIF.METADATA”), which we already receive using the
> “SimpleRTPSource” class - again (I presume), without requiring RTP header
> extensions.

These are already handled too.

> Support for RTP header extensions is probably going to be needed in the
> future for other applications (e.g., transmitting some WebRTC streams),
> but I want to understand where/why people might already be using them for
> other purposes.

That's understandable.
I've not seen any other uses of the extension header but understand that it's down to whatever the payload profile specifies.

Sadly we're at the manufacturer's mercy as to how they send this data, and while we can apply some pressure, they have no obligation to "do the right thing" :)

-- 
Deanna Earley | Lead developer | icatchercctv

w: www.icode.co.uk/icatcher | t: 01329 835335 | f: 01329 835338
Registered Office : 71 The Hundred, Romsey, SO51 8BZ. Company Number : 03428325