Change V4L2 Ext Controls via Libargus

[JanGerber]

Is it possible to set specific VIDIOC_S_EXT_CTRLS via the Libargus Camera API?

In particular it is about changing the data_rate of a RGB chip.

The chip offers the following settings (v4l2-ctl -L):

data_rate 0x009a206f (menu)   : min=0 max=7 default=0 value=2
                                0: 2376 Mbps/lane
                                1: 2079 Mbps/lane
                                2: 1782 Mbps/lane
                                3: 1485 Mbps/lane
                                4: 1440 Mbps/lane
                                5: 891 Mbps/lane
                                6: 720 Mbps/lane
                                7: 594 Mbps/lane

I have not yet been able to find the correct object in the documentation:
https://docs.nvidia.com/jetson/l4t-multimedia/group__LibargusAPI.html

[JerryChang]

hello gerber.jan456,

may I know what’s the actual use-case.
are you going to change data-rate dynamically while the camera is streaming?

[JanGerber]

In the first step we only want to set the data rate once at the beginning. However, in the second step we plan to change the data rate also during the operation of our application. The reason for this is that due to the bandwidth limitation of multiple cameras not every combination is possible (FPS, bit depth, size,…).

[JerryChang]

hello JanGerber,

may I know which Jetpack release, and which Jetson platform you’re used.
currently it’s not supported, (i.e. Jetpack-5.1/ l4t-r35.2.1)
FYI, it’s camera firmware taking MIPI clocks from device tree property settings for NVCSI configuration. that’s static value of each sensor mode, you cannot change NVCSI clocks through Argus pipeline.

[JanGerber]

Currently we are still using Jetpack version 32.6.1, as not all drivers support a newer version yet.

This is clear to me, since we have a fixed oscillator installed more accurately 24 Mhz and we know that we can only choose specific data_rates dependening on the used clock.