How do I get the RAW depth data?

Hi 

I am using the L515 as a part of my thesis. I have already used it to collect the data I need, and have used the rs-convert tool and MATLAB functions to access depth data stored in .bag files.

After my last talk with my supervisor, there is an issue that I hope to fix: 

For my recordings, which are all around 5 minutes, I am only getting around 1000 depth frames even though the sensor is specified at 30FPS. After doing some reading, it seems this is likely because I left the temporal filter and confidence threshold settings on default? Is it possible for me to access the raw depth data, for which there should be 30*60*5 = 9000 frames? Or is the device performing post-processing based on the temporal filter and confidence threshold settings in real-time and only has 1000 frames stored?

Also, I cant find the forum post that I read this on but I remember reading that I should discard the first few depth frames which were recorded? Can you please explain why we should discard frames and how many exactly should be discarded?

Thank you very much. Any help is appreciated.