@detail api
@author zhushufan.ref
@brief Get RTC SDK acquired video frame, according to the video pre-processor registerLocalVideoProcessor{@link #RTCEngine#registerLocalVideoProcessor} set, video pre-processing, the final processed video frame to the RTC SDK for encoding transmission.
@param frame RTC SDK captured video frames. See IVideoFrame{@link #IVideoFrame}.
@return The video frame after video preprocessing is returned to the RTC SDK for encoding and transmission. See IVideoFrame{@link #IVideoFrame}.
@note
- Before video preprocessing, you need to call registerLocalVideoProcessor{@link #RTCEngine#registerLocalVideoProcessor} to set up the video preprocessor.
- If you need to cancel the video preprocessing, you can set the video preprocessor to nullptr.