Recording online shows on an iMac

I sometimes watch shows on my iMac that I cannot download and are not on The Pirate Bay.

To record those shows, the following is needed : (picture)

The goal is to setup the USB to HDMI adapter as a second screen to the iMac and then split it between the TV and the HDMI to USB adapter so the signal comes back into the iMac.

Tip for the splitter : When the input port faces up and the logo faces you, output port 1 is to the bottom left and output port 2 is to the bottom right.

Here is a schematic :

The devices must be plugged in order :

  1. Turn on the TV.
  2. Plug the TV in port 1 of the splitter.
  3. Plug the HDMI to USB adapter between port 2 of the splitter and the iMac.
  4. Plug the USB to HDMI adapter between the iMac and the input port of the splitter.
  5. Plug the power to the splitter.

How to record a Doctor Who episode on Disney+.


You must then go into System Settings and configure the splitter as a second screen (it should be called 1to2) and the sound output to the splitter.

The sound will come out of the TV, not the iMac.

You may then move Safari to the second screen and make the video full screen.

To start recording :

  1. Open QuickTime.
  2. Select File > New Movie Recording.
  3. Select USB Video as the video input.
  4. Select USB Audio as the audio input.
  5. Set the output volume to zero (it already should be).
  6. Press the red record button and then start playing the video in Safari.

When the video ends, press the stop button in QuickTime. You may then save the video as a .mov file.


The TV must be plugged in port 1. If the HDMI to USB adapter is plugged in port 1, weird things will happen when the adapter gets reset (the iMac will see the splitter as disappearing and reappearing when it is used.)