JetPack 4.4 Start of frame Timestamp to monotonic raw

[georgi.dunchev1]

I’m porting a camera application from JP 4.5 to JP 4.4.1 so I can deploy it to Jetson AGX devices that are already sent to users and cannot be reflashed with newer versions.

On JP4.5 I was using SoF tsc to convert frame timestamp to Monotonic Raw. However on JP 4.4.1 I have only access to captMetaData->getSensorTimestamp();

I tried using the relation: monotonic_raw = - offset_ns
However testing on a couple of devices I got time difference from 10 to over 30 seconds! Also the value change after a restart.

Some data I’ve collected:

monotonic raw when processing the frame: 3816622730240ns
sensor timestamp: 3816660659000ns
offset-ns: 10791871936ns

Frame timestamp (SensorTimestamp - offset-ns) = 246242ms
Time stamp when I received the frame in the code = 257008ms
Timestamp from internal clock displayed on the screen when capturing the frame = 256834ms
From these I calculate:

1. there are 174ms delay from starting the camera capture, to the image arriving in the application;
2. There are 10592ms (10 seconds) of mismatch between actual and calculated start of frame timestamps

I’ll be happy to try and suggestions to solve this issue. Thanks

[JerryChang]

hello georgi.dunchev1,

instead of back porting the driver to earlier release version, how about Over-The-Air Updates to upgrade devices in the field.

[JerryChang]

BTW, please see-also Topic 159220 for comment #8 and #9 of the samples to get TSC HW timestamp.