Hardware accelerated gstreamer/nvvidconv convert from YUV* to RGB*?

Autonomous Machines Jetson & Embedded Systems Jetson AGX Xavier
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1

Hi,

I have a GMSL2 camera and it’s working as /dev/video0:

v4l2-ctl -d /dev/video0 -V
Format Video Capture:
	Width/Height      : 3840/2160
	Pixel Format      : 'YUYV'
	Field             : None
	Bytes per Line    : 7680
	Size Image        : 16588800
	Colorspace        : sRGB
	Transfer Function : Default (maps to sRGB)
	YCbCr/HSV Encoding: Default (maps to ITU-R 601)
	Quantization      : Default (maps to Limited Range)
	Flags             :

Can I say its raw format is YUYV? (I’m not sure)

If I tested it with videoconvert like this, it works:

gst-launch-1.0 -v v4l2src device=/dev/video0 ! 
'video/x-raw, width=3840, height=2160, format=YUY2, framerate=30/1' ! 
videoconvert ! 
'video/x-raw, width=3840, height=2160, format=BGRx, framerate=30/1' ! 
appsink caps='video/x-raw,format=BGRx' max-buffers=1

Please note that the first cap filter format is YUY2 because the test result show that YUYV does not work, which seems to conflicts with v4l2-ctl -d /dev/video0 -V result.

from the -v log below, I can see it’s converted to BGRx.

/GstPipeline:pipeline0/GstAppSink:appsink0.GstPad:sink: caps = video/x-raw, width=(int)3840, height=(int)2160, framerate=(fraction)30/1, interlace-mode=(string)progressive, format=(string)BGRx

Now I want to use nvvidconv to do the format convert to RGB/BGR or similar format, to use the hardware acceleration.

I replaced videoconvert by nvvidconv, but it does not work

gst-launch-1.0 -v v4l2src device=/dev/video0 ! 
'video/x-raw, width=3840, height=2160, format=YUY2, framerate=30/1' ! 
nvvidconv ! 
'video/x-raw, width=3840, height=2160, format=BGRx, framerate=30/1' ! 
appsink caps='video/x-raw,format=BGRx' max-buffers=1

I have run gst-inspect-1.0 nvvidconv and verified that nvvidconv supports YUY2 as source format and BGRx as sink format.
I don’t know why nvvidconv can’t replace videoconvert.

Any mistake I have made?

3

Hi,
Please try this sample and see if you can run it successfully:
V4l2src using OpenCV Gstreamer is not working in Jetson Xavier NX - #3 by DaneLLL

4

that example uses videoconvert, which is working fine here,
but I want to use nvvidconv.

5

Hi,
You have to use software converter in this use-case. Hardware converter does not support BGR. Here’s a similar topic for reference:
[Gstreamer] nvvidconv, BGR as INPUT - #2 by DaneLLL

6

what if I convert to BGRx ? I see it’s supported, but I can’t make it work

How do I force the conversion from YUY2 to BGRx?

7

Hi,
OpenCV doesn’t support BGRx, so we cannot send frame data in BGRx to appsink

8

I’m not useing full opencv’s gstreamer wrap, but GitHub - Myzhar/opencv_gstreamer_appsink: An useful class to acquire frame from a gstreamer pipeline and use them with OpenCV

the pipeline is open directly by gst_parse_launch( mPipelineStr.c_str(), &error );, and the appsink’s callback is handled by g_signal_connect( mSink, "new-sample", G_CALLBACK(on_new_sample_from_sink), this );, so OpenCV’s limitation doesnot apply in my case.

On the contrary, I have sucessfully got BGRx data from the callback (for videoconvert pipeline).

What I want now is to embed nvvidconv into my pipeline (to replace videoconvert)

9

Hi,
Please try

gst-launch-1.0 -v v4l2src device=/dev/video0 ! 
'video/x-raw, width=3840, height=2160, format=YUY2, framerate=30/1' ! 
nvvidconv ! 'video/x-raw(memory:NVMM),format=RGBx' ! nvvidconv ! 
'video/x-raw, width=3840, height=2160, format=BGRx, framerate=30/1' ! 
appsink caps='video/x-raw,format=BGRx' max-buffers=1

The nvvidconv supports

video/x-raw ! nvvidconv ! video/x-raw(memory:NVMM)

video/x-raw(memory:NVMM) ! nvvidconv ! video/x-raw

Does not support

video/x-raw ! nvvidconv ! video/x-raw

You may also try this patch:
Macrosilicon USB - #5 by DaneLLL
So that you can run like:

nvv4l2camerasrc ! 'video/x-raw(memory:NVMM),format=YUY2' ! nvvidconv ! video/x-raw,format=BGRx ! appsink
1 Like
10

Never knew that! indeed, it’s my first time to hear about it!

12

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