Modifying frames with OpenCV before writing to encoded video file

[voxluser12341]

Hi, I'd like to develop a program very similar to voxl-record-video for the camera i have connected as hires, except that upon receiving a frame, I want to edit it using OpenCV's drawing functionalities, specifically arrowedLine() and putText(), before writing it to file. In voxl-record-video, I believe that the frame is already encoded when received as a char*. Is there a way to transform this into a matrix of pixel values that OpenCV's methods can work with, then transform it back into the format it needs to be in to be written to video? Or is there another approach that you recommend to do this?

[voxluser12341]

It seems that a similar functionality has been shown in an experimental python branch: https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-mpa-tools/-/blob/pympa-experimental/tools/python/pympa-resize.py. Is this a recommended way to go about this (if so, how do I get these libraries and their C-bindings onto my voxl2) or is there an easier approach?