Graders can leave audio/video feedback by directly making an audio/video recording on the Assignment Activity.
When recording an audio/video feedback, the limit is 2 minutes.
Step 1: Go to the Assignment activity where you want to leave audio/video feedback.
Step 2: Click on the Grade button.
Step 7: You can playback your recording or choose to record again, once satisfied with the recorded audio, click on the "Attach recording".
Step 8: You can now see that the audio feedback file is attached in the comments section, to complete the process, click on "Save changes"

The above steps can be followed to make a video recording of the feedback as well.
Click the

icon from the Feedback comments editor box to record video feedback and follow the same steps listed out above.
Browser should be allowed to access the camera to use this feature.