How to see if frames got dropped?

[snopytas]

---

Required Info
Camera Model	D435i
Operating System & Version	Ubuntu 18.04
Kernel Version (Linux Only)	5.4
Platform	PC
SDK Version	2
Language	C/C++

Issue Description

Hi,

I'm receiving frames via pipe.poll_for_frames() . I would like to see (or get notified) if frames get dropped because they couldn't get polled fast enough.

I'm already saving debug and info messages with rs2::log_to_file(RS2_LOG_SEVERITY_ALL,"logfile.log") but I can't see anything in the logfile which indicates that a frame got dropped, even if I artificially delay the processing, e.g.

rs2::log_to_file(RS2_LOG_SEVERITY_ALL,"LOG.log");
rs2::frameset data;
while(true) {
    if (pipe.poll_for_frames(&data)) {
        ... do some stuff ...
        ...wait for 500ms ...
    }  
}

How can I see if a frame got dropped?

Thanks and best regards

[MartyG-RealSense]

Hi @snopytas There is a discussion in the link below with information about how frame drops are calculated in the SDK.

#7488 (comment)

That discussion points to a group of C++ lines in the SDK that are responsible for frame drop calculation. This will hopefully be a helpful reference that you can adapt for your own project.

https://github.com/IntelRealSense/librealsense/blob/master/common/output-model.cpp#L1099-L1108

[snopytas]

Thank you @MartyG-RealSense. The documentation says that a frame drop would be visible in the debug log, but I don't see it. Maybe it could be due to the fact that for the moment I'm playing a recorded file (Homeoffice) instead of using the real camera.

Anyway, I was able to adapt the code you referenced and this is sufficient for my purposes. So this issue is solved for me. Thank you very much!

[MartyG-RealSense]

You are very welcome @snopytas :) If you are satisifed with the outcome of the case, please feel free to close it with the Close Issue button beneath the comment writing box. Thanks again!