How to Fix Discoloration from HDMI output of some Mac computers

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Justin Hartman
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Symptom: Some users experience a discoloration when outputting HDMI (either directly or via a DisplayPort or Thunderbolt converter) from some Mac computers into the BoxCaster. Some other Mac computers appear fine, as do Windows computers, cameras, video mixers, etc.

Background Information: The BoxCaster is able to receive video from HDMI sources in two different colorspaces: RGB and YUV. Cameras and other "native" video devices (like video mixers) typically choose the YUV colorspace. Windows computers typically choose the RGB colorspace. Some Mac computers choose the YUV colorspace, but do not properly map their screens' RGB pixel values into YUV. This is a known issue with certain Macs with certain graphics chipsets.

When receiving YUV, the BoxCaster simply uses the color values it receives over HDMI and does not adjust them in any way (other than to compress the images using h.264). This means that any colorspace adjustments need to be done by the source device, which in this case, means the Mac computer.

Solutions:

  • Use another device: while not possible in every case, you may wish to try using a Windows computer, or potentially a different Mac (as different graphic chipsets may exhibit different behavior).
  • Use a different graphics adapter: some people have reported success using an external USB or Thunderbolt graphics adapter.
  • Send the video through another device: for example, a Decimator MD-HX (or other similar scaler/format converter) may receive a cleaner signal from the Mac, and it is known to send a good signal to the BoxCaster.
  • Use a custom color profile: follow the instructions below to import a custom color profile which you can use when sending video to the BoxCaster.
  • Create your own custom color profile: if you have a good eye and want to customize the colorspace conversion of your Mac, follow the instructions below to customize a color profile.

Using a custom color profile

BoxCast has created a basic custom color profile which, while not perfect, comes much closer to natural colors than the built-in Mac driver. To download and use this profile:

  1. Download the attached BoxCaster.icc color profile.

  2. Open Finder, then go to the menu and choose Go -> Go To Folder...

  3. Enter ~/Library/ColorSync/Profiles and click Go or hit Enter.

  4. Copy the downloaded file (BoxCaster.icc) into the folder you opened in your Finder window in step 3.

  5. Plug the BoxCaster into the computer's HDMI output (or attached DisplayPort/Thunderbolt HDMI adapter).

  6. Open Displays Preferences...

    Note: You can typically find this at the top of your screen in a status menu; if not, choose System Preferences... in the upper-left-hand Apple menu, then click on Displays.

  7. On the display preferences for the BoxCaster, choose the Color tab.

    Note:     the built-in display will usually be called Built-In Retina Display or similar, while the BoxCaster may show up as BoxCaster, Display, External Display, or similar.

    Also note: if you don't see the BoxCaster's display window, click the Gather Windows button.

  8. Choose BoxCaster from the color profile list.

[Advanced] Creating a custom color profile

To create and use a custom color profile:

  1. Connect your BoxCaster to the computer's HDMI output and start a stream.

  2. From your dashboard, click on the live broadcast's title to see the event details.

  3. Click the Show Preview button to play a low-latency preview of your broadcast. This allows you to see changes and adjustments quickly.

  4. Open Displays Preferences....

    Note: You can typically find this at the top of your screen in a status menu; if not, choose System Preferences... in the upper-left-hand Apple menu, then click on Displays.

  5. On the display preferences for the BoxCaster, choose the Color tab.

    Note:     the built-in display will usually be called Built-In Retina Display or similar, while the BoxCaster may show up as BoxCaster, Display, External Display, or similar.

    Also note: if you don't see the BoxCaster's display window, click the Gather Windows button.

  6. While holding down the Option key on your keyboard, click on Calibrate...

  7. Making sure to leave Expert Mode checked, follow the directions to calibrate and create your own color profile.

    Note: you may wish to move your browser and preferences windows around so that you can see both windows while making changes.