Exposure control

[saki4510t]

Exposure control

[saki4510t]

Hi,
Thank you for providing information and question.
Well as you know this repository is based on libusb and libuvc and livubc implemented video control functions with wrong way(currently works well). If you use older fork, I assume it will be better to check/compare ctrl.c and apply it as possible as you can.

The actual values that each camera control function can accept depends on each camera and it does not depend on UVC version. You need to get them using UVC_GET_MIN, UVC_GET_MAX, UVC_GET_RES etc.

We can independently use most of other camera control functions. But regarding exposure, there are four camera control functions in UVC specification directly related to exposure; Auto-Exposure Mode Control, Auto-Exposure Priority Control, Exposure Time(Absolute) Control and Exposure Time (Relative) Control. And they strongly depend on each other.
Unfortunately they sometimes depend on other camera functions like Iris (Absolute) control, Iris (Relative) Control and acceptable frame rate etc. and your need to use available combination of values only. So if your camera does not work well on some condition, the reason is just simple, because the value was not a acceptable value on the current camera state.
As described in UVC specification, if you set wrong value to camera control function, the control shall result in a protocol STALL and an error code of bRequestErrorCode="Wrong state" and you need to reset. You need to read UVC specification very well and test well with the camera that you want to use.

Totally, controlling exposure is difficult than other functions and some cameras do not support this control and I have not tested well yet and don't know the best way to get available vales and get it work well for all camera that have exposure control.
saki

[saki4510t]

closed due to inactivity.