Displaying camera not working

[Antonio Ospite]

On Mon, 23 Apr 2018 16:26:42 +0200
Iñigo Huguet <inigohuguet at fanamoel.com> wrote:

> I have managed to solve a problem: it seems that the sprite was not well 
> reported by the driver (it said it was 1080 instead of 720). Now I think 
> it gives the correct values for a 720x576px NV12 frame: sprite 720, size 
> 622080
> 
> However, I still doesn't have a good output, and I don't know what to do 
> to find what's wrong (I have no previous experience with video nor 
> gstreamer).
> 
> With this pipeline: gst-launch-1.0 v4l2src device=/dev/video1 ! 
> video/x-raw,format=NV12,width=720,
> height=576 ! videoconvert ! xvimagesink sync=false
> 
> I only get an output with very colorful lines (almost horizontal lines).
> 
> I attach the output of the driver and gstreamer with 
> GST_DEBUG=*videosink*:6,*imagesink*:6,*v4l2*:6
> 
> Any hint? Thanks!
> 

If you cannot trust the driver to report the correct data format (I am
thinking to the pixelformat in particular), then GStreamer videoconvert
won't be able to use the caps in any meaningful way.

You could analyze a raw frame to confirm that it's actually NV12.

A sample pipeline which (hopefully) dumps one frame is:

  gst-launch-1.0 v4l2src num-buffers=1 device=/dev/video1 ! filesink location=raw_frame.bin

Upload the raw data somewhere and maybe someone will take a look
if they have time.

Ciao,
   Antonio

-- 
Antonio Ospite
https://ao2.it
https://twitter.com/ao2it

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