microsoft / HoloLens2ForCV

Sample code and documentation for using the Microsoft HoloLens 2 for Computer Vision research.
MIT License
494 stars 144 forks source link

Stream Recorder: VLC frames have incorrect timestamps (frames out of order) #86

Open nickgreene opened 3 years ago

nickgreene commented 3 years ago

When recording using StreamRecorder it seems that the timestamps returned by all of the visible light cameras are frequently incorrect resulting in an out of order sequence of frames.

To confirm this, I made a recording while looking at a stopwatch with each visible light camera. There are many frames where the reading on the stopwatch is lower than the previous frame (despite the frame's larger timestamp). Sometimes a disruption lasting more than 5 frames happens before the timesteps seem to become correct again.

This happens often enough for it to be a serious inconvenience. For a rough idea, I counted 12 times where the stopwatch time decreased compared to the previous frame in a 10 second recording. The out of order frames are very noticeable in the resulting video playback.

I tried using timestamp.SensorTicks instead of timestamp.HostTicks in RMCameraReader.cpp but the issue persisted.

This does not happen with the PV frames or with either mode of the depth sensor frames.

I'm using the latest insider preview build: Windows Version 21H1, OS build 20346.1402

I may be wrong but I do not recall this issue occurring with the first few insider builds that supported research mode, however, I couldn't find the older insider builds online to try.

Is there any way to fix this issue?

Thanks a lot!

evia100 commented 2 years ago

same problem here. did you managed to make it work?

jondebug commented 2 years ago

same here.. any update??