Fixing incorrect colour matrices

  1. Open the script in Aegisub.
  2. Load your video.
  3. Open the resample dialog.
    4. The resample button’s location in the Aegisub toolbar.
    The resample button’s location in the Aegisub toolbar.
  4. It should be automatically set to the correct values.
    5. TV.601 -> TV.709
    TV.601 -> TV.709

    I don’t want to resample the resolution, so I’ll just set it back to the original 1920x1080.

  5. Press OK.

Yes, it’s that easy.

You can also use this automation script.

Now turn off Force BT.601 or switch to a newer fork of Aegisub so you never have to do this again.