Tx2 gst-launch usb v4lerror

Robotics & Edge Computing Jetson Systems Jetson TX2
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1

Hi

I have the following result using :

gst-launch-1.0 v4l2src device="/dev/video0" ! qtdemux ! queue ! h264parse ! nvv4l2decoder enable-max-performance=1 ! nv3dsink -e
AVERTISSEMENT : pipeline erroné : impossible de connecter v4l2src0 à qtdemux0

same with at te end : xvimagesink -e

this one work:
gst-launch-1.0 v4l2src device="/dev/video0" ! "video/x-raw, width=640, height=480, format=(string)YUY2" ! xvimagesink -e

For information My v4l gst :

gst-inspect-1.0 | grep v4l
video4linux2:  v4l2src: Video (video4linux2) Source
video4linux2:  v4l2sink: Video (video4linux2) Sink
video4linux2:  v4l2radio: Radio (video4linux2) Tuner
video4linux2:  v4l2deviceprovider (GstDeviceProviderFactory)
nvvideo4linux2:  nvv4l2vp9enc: V4L2 VP9 Encoder
nvvideo4linux2:  nvv4l2vp8enc: V4L2 VP8 Encoder
nvvideo4linux2:  nvv4l2h265enc: V4L2 H.265 Encoder
nvvideo4linux2:  nvv4l2h264enc: V4L2 H.264 Encoder
nvvideo4linux2:  nvv4l2decoder: NVIDIA v4l2 video decoder

and

gst-inspect-1.0 --version
gst-inspect-1.0 version 1.14.5
GStreamer 1.14.5
https://launchpad.net/distros/ubuntu/+source/gstreamer1.0

Package: nvidia-jetpack
Version: 4.3-b134
Architecture: arm64

thank’s

3

Hi,
Please follow the steps and check if you can launch the camera successfully:
Jetson Nano FAQ
Q: I have a USB camera. How can I launch it on Jetson Nano?

4

hi Danel,

this original one works :

gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,format=YUY2,width=640,height=480,framerate=30/1 ! nvvidconv ! ‘video/x-raw(memory:NVMM),format=NV12’ ! nvoverlaysink

this one modified (no NV12) works :

gst-launch-1.0 v4l2src device=/dev/video0 ! video/x-raw,format=YUY2,width=640,height=480,framerate=30/1 ! xvimagesink -e

but this don’t work :

gst-launch-1.0 v4l2src device=/dev/video0 ! qtdemux ! queue ! h264parse ! nvv4l2decoder enable-max-performance=1 ! xvimagesink -e
with :
AVERTISSEMENT : pipeline erroné : impossible de connecter v4l2src0 à qtdemux0

5

Hi,
The failure is expected. The qtdemux plugin is for parsing mp4 file. Your source is not a mp4 file, so it cannot link to qtdemux.

6

Thanks for your help.

-is it always for mp4 ?
-if not, in my case, how I can modify to obtain best performance via accelerated ?
thanks.

7

Hi,
You may apply this patch to rebuild nvv4l2camerasrc:
Macrosilicon USB - #5 by DaneLLL

So that the frame data can be captured into NvBuffer directly. This is zero copy.