ExtractFdFromNvBuffer does not work with v4l2src ! nvvidconv

Accelerated Computing Intelligent Video Analytics DeepStream SDK
1

We have a plugin that uses ExtractFdFromNvBuffer. It fails when the source is v4l2src.

This works:
gst-launch-1.0 v4l2src ! nvvidconv ! ‘video/x-raw(memory:NVMM),format=NV12’ ! nvegltransform ! nveglglessink -e

But not this:
gst-launch-1.0 v4l2src ! nvvidconv ! ‘video/x-raw(memory:NVMM),format=NV12’ ! nvtracker ! nvegltransform ! nveglglessink -e

Getting
PosixMemMap:71 [9] mmap failed
nvcaffe-gie Buffer mapping failed
nvbuf_utils: dmabuf_fd 1828717655 mapped entry NOT found
nvbuf_utils: Can not get HW buffer from FD… Exiting…

Presumably nvtracker uses ExtractFdFromNvBuffer too.

We are using a WebCam

2

Hi,
Do you use DS1.5/TX2? It is not supported on this release.

Furthermore, nvtracker needs matadata from previous nvcaffegie. Your pipeline is not valid.

3

ExtractFdFromNvBuffer in our plugin works when nvvidconv is the source. This works in all cases we have tried except when v4l2src feeds nvvidconv. Why is this so?

4

Hi,
Please share how you construct ExtractFdFromNvBuffer() and nvvidconv in your usecase.

Maybe run ‘appsrc ! nvvidconv ! appsink’ and call ExtractFdFromNvBuffer() in appsink? And where to put nvtracker? nvtracker works as expected without nvcaffegie?

5

For more about ExtractFdFromNvBuffer(), please also refer to
[url]https://devtalk.nvidia.com/default/topic/1050254/deepstream-sdk-on-jetson/nvreleasefd-in-gstdsexample-cpp/post/5330444/#5330444[/url]