AW: Displaying camera not working

[Bernhard Graaf]

Have you try to use playbin2 instead?
Something like 'gst-launch-1.0 playbin2 uri=v4l2:///dev/video1'.
If its works, have a look into the log and see what playbin2 had done.

Bernhard

-----Ursprüngliche Nachricht-----
Von: gstreamer-devel [mailto:gstreamer-devel-bounces at lists.freedesktop.org]
Im Auftrag von Iñigo Huguet
Gesendet: Dienstag, 24. April 2018 11:13
An: Antonio Ospite; gstreamer-devel at lists.freedesktop.org
Betreff: Re: Displaying camera not working

Hi.

I have gotten one frame as you told me

gst-launch-1.0 v4l2src num-buffers=1 device=/dev/video1 ! 
video/x-raw,format=NV12,width=720,height=576 ! filesink 
location=raw_frame.bin

Then, in my computer, I converted it to png:

gst-launch-1.0 -v filesrc location=raw_frame.bin ! videoparse width=720 
height=576 format=GST_VIDEO_FORMAT_NV12 ! videoconvert ! pngenc ! 
filesink location=raw_frame.png

I can see the .png image correctly, so it seems that the driver outputs 
NV12. What can I try now? Maybe I need any additional plugin? (I'm using 
a custom build using Buildroot so I don't have all plugins installed)

El 23/04/18 a las 17:09, Antonio Ospite escribió:
> 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
>

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