pipe string wanted

[Marianna Smidth Buschle]

You will have to write a small python app for that, you should be able 
to find some tutorials on that.
(fx https://lifestyletransfer.com/how-to-use-gstreamer-appsink-in-python/)

If your camera only provides YUYV, you will have to convert to BGR 
(opencv expects BGR).

So something like:

|"v4l2src ! videoconvert ! \ capsfilter caps=video/x-raw,format=BGR ! \ 
appsink emit-signals=True"|

Alternatively if you have gstreamer enabled in opencv you can do 
something like:

|cv2.VideoCapture('videotestsrc ! video/x-raw,framerate=20/1 ! 
videoscale ! videoconvert ! appsink',cv2.CAP_GSTREAMER)|

https://answers.opencv.org/question/202017/how-to-use-gstreamer-pipeline-in-opencv/


 > But I have no idea how to make the pipe string that should go to the 
gst-launch-1.0

Google is your friend ;P


Best Regards

Marianna

On 02.03.2023 13.00, gstreamer-devel-request at lists.freedesktop.org wrote:
> Message: 3
> Date: Thu, 2 Mar 2023 10:54:00 +0900
> From: H Jumogehn<jumogehn at gmail.com>
> To:gstreamer-devel at lists.freedesktop.org
> Subject: pipe string wanted
> Message-ID:
> 	<CAJp4miLc=p96bDn90HRWs3sb+36ZGvfz_ELXkm1MQOwOhwcjyg at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hello,
> I?d like to use gstreamer to capture video images(RGB/BGR), frames(RGB/BGR)
> from my V4L2 camera.
> The output of v4l2-ctl is shown below:
>
>
> $ vl42ctl -d /dev/video0 --all
>
> Driver Info (not using libv4l2):
> Driver name   : basa
> Card type     : FPD1-0103
> Bus info      : PCI:0000:09:00.0
> Driver version: 5.4.143
> Capabilities  : 0x84200001
> Video Capture
> Streaming
> Extended Pix Format
> Device Capabilities
> Device Caps   : 0x04200001
> Video Capture
> Streaming
> Extended Pix Format
> Priority: 2
> Video input : 0 (FPD1-0103: ok)
> Format Video Capture:
> Width/Height      : 1920/1080
> Pixel Format      : 'YUYV'
> Field             : None
> Bytes per Line    : 3840
> Size Image        : 4147232
>
>
> But I have no idea how to make the pipe string that should go to the
> gst-launch-1.0
> Could you suggest to me a good gstreamer pipe string for my camera?
>
> I?d like to use as much H/W accellerations as possible that the Nvidia
> RTX2080 provides.
>
> The source would be the camera above.
> The sink should be the appsink. But with the gst-launch-1.0 the sink can be
> fakesink.
> The application that receives data from the appsink must receive RGB or BGR
> data and upon this data opencv will be used and applied to process many
> vision algorithms.
>
> Thank you!

-- 
Best regards / Med venlig hilsen
“Marianna Smidth Buschle”
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