# V4l2src & nvvideoconvert connection issue **URL:** \ **Category:** DeepStream SDK\ **Created:** [September 21, 2023, 7:08am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108 "2023-09-21T07:08:59Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![PrabakaranR](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@PrabakaranR](https://forums.developer.nvidia.com/u/PrabakaranR)\ **Post date:** [September 21, 2023, 7:08am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/1 "2023-09-21T07:08:59Z")
Please provide complete information as applicable to your setup. **• Hardware Platform (DGPU)** **• DeepStream Version - 6.2** **• JetPack Version (valid for Jetson only)** **• TensorRT Version** **• NVIDIA GPU Driver Version (valid for GPU only) - 535** **• Issue Type( questions, new requirements, bugs) - Questions** **• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)** **• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)** **[Note: I am using NV Docker container]** Hi, I am trying to run deepstream gst pipeline using v4l camera. Some point to note that I am able to successfully do the below things 1. Able to run “deepstream-app -c source1\_usb\_dec\_infer\_resnet\_int8.txt” 2. Able to check the device by v4l2-ctl -d /dev/video0 --list-formats-ext. Below is the output ioctl: VIDIOC\_ENUM\_FMT Type: Video Capture Now, when I try to run the below pipeline “gst-launch-1.0 v4l2src device=/dev/video0 ! ‘video/x-raw,format=YUY2,width=640,height=480,framerate=30/1’ ! nvvideoconvert ! ‘video/x-raw(memory:NVMM),format=NV12’ ! m.sink\_0 nvstreammux name=m batch-size=1 width=1280 height=720 ! fakesink” I am getting error as below **“WARNING: erroneous pipeline: could not link v4l2src0 to nvvideoconvert0, nvvideoconvert0 can’t handle caps video/x-raw, format=(string)YUY2, width=(int)640, height=(int)480, framerate=(fraction)30/1”** Kindly clarify. ---
**Author:** ![yuweiw](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/yuweiw/32/101255_2.png) [@yuweiw](https://forums.developer.nvidia.com/u/yuweiw)\ **Post date:** [September 21, 2023, 10:47am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/3 "2023-09-21T10:47:03Z")
What’s the format of your camera video? ---
**Author:** ![PrabakaranR](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@PrabakaranR](https://forums.developer.nvidia.com/u/PrabakaranR)\ **Post date:** [September 21, 2023, 11:26am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/4 "2023-09-21T11:26:15Z")
It is ‘YUYV’ (YUYV 4:2:2). v4l2-ctl -d /dev/video0 --list-formats-ext returns below. ioctl: VIDIOC\_ENUM\_FMT Type: Video Capture ``` [0]: 'MJPG' (Motion-JPEG, compressed) Size: Discrete 1280x720 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 160x120 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 176x144 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 320x240 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 352x288 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 640x480 Interval: Discrete 0.033s (30.000 fps) **[1]: 'YUYV' (YUYV 4:2:2)** Size: Discrete 1280x720 Interval: Discrete 0.100s (10.000 fps) Size: Discrete 160x120 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 176x144 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 320x240 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 352x288 Interval: Discrete 0.033s (30.000 fps) Size: Discrete 640x480 Interval: Discrete 0.033s (30.000 fps) ``` ---
**Author:** ![yuweiw](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/yuweiw/32/101255_2.png) [@yuweiw](https://forums.developer.nvidia.com/u/yuweiw)\ **Post date:** [September 22, 2023, 5:30am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/5 "2023-09-22T05:30:34Z")
But you set the format to `YUY2` in your pipeline. Could you try to change that and run the pipeline? ---
**Author:** ![PrabakaranR](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@PrabakaranR](https://forums.developer.nvidia.com/u/PrabakaranR)\ **Post date:** [September 22, 2023, 5:43am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/6 "2023-09-22T05:43:12Z")
But it is still giving the same error WARNING: erroneous pipeline: could not link v4l2src0 to nvvideoconvert0, neither element can handle caps video/x-raw, format=(string) **YUYV** , width=(int)640, height=(int)480, framerate=(fraction)30/1 BTW, Earlier I had set it to YUY2 (even though my format is YUYV) based on one of the comment from NVIDIA member on this post. > [@DeepStream SDK FAQ](https://forums.developer.nvidia.com/t/deepstream-sdk-faq/80236/36): > > 28. [DSx\_All\_App] How to connect a USB camera in DeepStream? 28.1 Query the device number by the v4l2-ctl tool E.g. $ sudo apt install v4l-utils && v4l2-ctl --list-devices 28.2 Query the supported formats and capabilities of the camera by v4l2-ctl tool. E.g. Query the camera’s formats and capabilities whose device number is 2. $ v4l2-ctl -d /dev/video2 --list-formats-ext The information may be displayed in the following format ioctl: VIDIOC\_ENUM\_FMT Type: Video Capture octl: VIDIOC\_EN… **However, even if I give YUYV, it still throws same error** Command used this time : gst-launch-1.0 v4l2src device=/dev/video0 ! ‘video/x-raw,format=YUYV,width=640,height=480,framerate=30/1’ ! nvvideoconvert ! ‘video/x-raw(memory:NVMM),format=NV12’ ! m.sink\_0 nvstreammux name=m batch-size=1 width=1280 height=720 ! fakesink ---
**Author:** ![yuweiw](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/yuweiw/32/101255_2.png) [@yuweiw](https://forums.developer.nvidia.com/u/yuweiw)\ **Post date:** [September 22, 2023, 6:07am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/7 "2023-09-22T06:07:39Z")
OK. Could you refer to the `28.3.2` of the FAQ and try to add a videoconvert first? ---
**Author:** ![PrabakaranR](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@PrabakaranR](https://forums.developer.nvidia.com/u/PrabakaranR)\ **Post date:** [September 22, 2023, 7:02am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/8 "2023-09-22T07:02:52Z")
It worked. Thanks for the support. ---
**Author:** ![PrabakaranR](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@PrabakaranR](https://forums.developer.nvidia.com/u/PrabakaranR)\ **Post date:** [September 22, 2023, 9:56am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/9 "2023-09-22T09:56:19Z")
BTW, Using the same camera set up, When I run “deepstream-app -c source1\_usb\_dec\_infer\_resnet\_int8.txt”, the video runs smoothly without any lag. However, when I try the below gst pipeline, the video lags a lot and not smooth and I also get message like “WARNING: from element /GstPipeline:pipeline0/GstEglGlesSink:eglglessink0: A lot of buffers are being dropped.” gst-launch-1.0 v4l2src device=/dev/video0 ! ‘video/x-raw,format=YUY2,width=640,height=480,framerate=30/1’ ! videoconvert ! ‘video/x-raw, format=NV12’ ! nvvideoconvert ! ‘video/x-raw(memory:NVMM),format=NV12’ ! m.sink\_0 nvstreammux name=m batch-size=1 width=1280 height=720 ! nvinfer config-file-path=/opt/nvidia/deepstream/deepstream/samples/configs/deepstream-app/config\_infer\_primary.txt batch-size=1 unique-id=1 ! nvtracker ll-lib-file=/opt/nvidia/deepstream/deepstream/lib/libnvds\_nvmultiobjecttracker.so ! nvmultistreamtiler rows=1 columns=1 width=1280 height=720 ! nvvideoconvert ! nvdsosd ! nveglglessink Am I missing in the pipeline? Thanks ---
**Author:** ![yuweiw](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/yuweiw/32/101255_2.png) [@yuweiw](https://forums.developer.nvidia.com/u/yuweiw)\ **Post date:** [September 25, 2023, 10:49am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/10 "2023-09-25T10:49:50Z")
You can try to set the same parameter of each plugin. Like nvstreammux, you can set the `batched-push-timeout=40000`, `live-source=1`, etc… ---
**Author:** ![PrabakaranR](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@PrabakaranR](https://forums.developer.nvidia.com/u/PrabakaranR)\ **Post date:** [September 30, 2023, 5:50am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/11 "2023-09-30T05:50:31Z")
Thanks. When I used sync=0, it worked ---
**Author:** ![system](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/system/32/68080_2.png) [@system](https://forums.developer.nvidia.com/u/system)\ **Post date:** [October 14, 2023, 5:51am UTC](https://forums.developer.nvidia.com/t/v4l2src-nvvideoconvert-connection-issue/267108/12 "2023-10-14T05:51:28Z")
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