nvcamerasrc exposure-time not working

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

Hi all,

We have tried to disable the auto exposure and manually specify an exposure time using nvcamerasrc, but without any apparent effect. This is documented and should really work, so I am wondering why we cannot make it work.

Is this mode of operation sensor specific? Can someone share a minimal working pipeline using nvcamerasrc?

Best regards,
Adh

2

Could you use argus?

3

I also came across this problem with nvcamerasrc and played a bit with argus but in some experiments I found that calls in the form of “iNativeBuffer->copyToNvBuffer(buffer_fd);” are rather slow on our TX1 device but this seems to be the only way to get workable pixel buffers.

Also: we would like to work with gstreamer and perhaps the NVIDIA DeepStream SDK so it would be convenient to have a working gstreamer source.

Currently can launch a gstreamer chain from nvcamerasrc and we override whatever settings is makes regarding exposure-time and gain using direct v4l2 comments but of course this is rather hacky and we would prefer a clean solution.

Do you think that you can either implement auto-exposure, exposure-time, gains, etc. in nvcamerasrc or perhaps release the source code of this component such that we can implement it ourselves?

4

For the nvcamerasrc you can check with the nvgstcaptrue-1.0 and implement your own gst APP

http://developer.nvidia.com/embedded/dlc/nv-gst-apps-sources-r2423

5

Hi ShaneCCC,

I checked nvgstcapture and I looked for exposure time related settings. So there is a function:

void
set_exposureTime (gfloat dval)
{
  app->exposureTime = dval;
  g_object_set (G_OBJECT (app->ele.vsrc), "auto-exposure", 1, NULL);
  g_object_set (G_OBJECT (app->ele.vsrc), "exposure-time", dval, NULL);
}

This is basically calling a set_property on whatever app->ele.vsrc is so let’s go figure out what this is.

app->ele.vsrc = gst_element_factory_make (NVGST_VIDEO_CAPTURE_SRC_CSI, NULL);

And if I then go and find that define:

#define NVGST_VIDEO_CAPTURE_SRC_CSI "nvcamerasrc"

So this application just secretly uses nvcamerasrc and will also not have working exposure-time control… It seems kind of a waste of time to be implementing our own v4l2-based gstreamer src trying to optimally get this to work nicely in NVMM zero-copy memory while NVIDIA has this nvcamerasrc which actually works well but is just not finished.

OK it works in argus and in some NVIDIA repositories I find a mention to something called nvargussrc but this one also does not seem to support exposure control and appears to be black-box and totally closed source.

Again in the context of this DeepStream SDK that NVIDIA is promoting I imagine that control over gain and exposure time is important in many real-time video processing applications so it would be nice to have better support for this from the provided sdks.

6

For the argus the API setExposureCompensation() may help.

virtual Status Argus::IAutoControlSettings::setExposureCompensation	(	float 	ev	)
7

I had already successfully used the Argus functions:

virtual Status Argus::ISourceSettings::setExposureTimeRange(const Range<uint64_t> &exposureTimeRange)
virtual Status Argus::ISourceSettings::setGainRange(const Range<float>& gainRange)

So these work but this does not solve the problem of the topic starter or myself because we need DeepStream/gstreamer pipelines. I guess I can try to figure out how to make a gstreamer source out of this Argus application but you at NVIDIA already have this and have probably implemented a lot of nice optimizations using zero-copy memory, buffer re-use, etc.

Also: I have asked this same question to some people from the DeepStream team at GTC Europe this year and they seemed to never even have heard about Argus.