Low Latency Interlaced Video

[Tim Müller]

On Fri, 2014-09-05 at 15:12 +0100, Paul Barber wrote:

Hi Paul,

> What is the best way to deal with a truly interlaced video source?
> 
> I have written a source plugin for the VRMagic USB frame grabber 
> (VRMAVC-2), and for the lowest latency I can configure it to send me 
> individual fields at 50 fps (each half-frame height). I would like to 
> have a downstream element that will combine these fields (e.g. weave 
> them) into a full frame, still at 50 fps. Does such an element or sink 
> exist?
> 
> Alternatively, I can configure the source to send interlaced frames at 
> 25 fps, and use the "deinterlace" element to construct full frames at 50 
> fps. This looks very nice, but I am hoping to reduce the latency by 
> working with fields were possible.

We don't really have proper infrastructure for sending single fields
through the pipeline [*], and I'm not aware of any plugins handling that
properly or at all.

Why is the sub-frame latency important to you here? Do you immediately
output the captured fields on a device that outputs interlaced video
whilst also wanting to do other things like record the stream to a file
in other branch of the pipeline, and that's where you do the
deinterlacing then?

 Cheers
  -Tim

[*] other than GST_VIDEO_BUFFER_FLAG_ONEFIELD

-- 
Tim Müller, Centricular Ltd - http://www.centricular.com