Originally Posted by tts42572
What's the difference between "normal" and "auto" for this HDMI Black level setting in terms of picture quality?
The "HDMI Black Level" setting is only available (not "grayed-out") when the input signal, from a device connected to the TV via HDMI, is set to RGB.
All video discs, including Blu-rays, DVDs and Video CDs, are encoded as YCbCr which has a native "limited" color range of 16-235 (for 8-bit sources). Most HDMI devices (Blu-ray players, Satellite receivers, Cable boxes) will output a YCrCb signal. It is best to set these source components to output YCbCr not
An HDMI device that can output an RGB signal (Computer, Gaming console) can usually be set to output either a "limited" (Video level) color range of 16-235 or a "full" (PC level) color range of 0-255.
A "Full-Range" RGB signal of 0-255 refers to the number of color shades that are available in each of the Red, Green, and Blue channels (for a total of 16.78 million possible colors - ranging from Blacker-than-Black to Whiter-than-White). For a "Limited-Range" signal (16-235), a total 10.65 million colors/shades will be available.
When playing back a "Limited-Range" (16-235) RGB signal (Video level), you should set "HDMI Black Level" setting to "Low". When playing back a "Full-Range" (0-255) RGB signal (PC level), you should set it to "Normal".
But to answer your question, the "Auto" setting might not always switch the TV to the "Full" RGB mode when input a "Full-range" signal. Therefore, it is always preferable to switch it manually to match the input signal.
Again, when a YCrCb signal is detected, the "HDMI Black Level" setting will be unavailable ("grayed-out").