3/19/2016

HDMI, its not the Cable

LCD computer monitors often double as a video monitors with many choices of Input connector, when switching from DVI to HDMI, often the fonts are [halo'ed] [strobe'd] or too blurry or hard to read. Its usually not the cable, and its almost never documented in the User's Guide. Here's how to fix that.

LCD monitors are often tuned at the factory with several presets, in addition to many manual settings available in on screen displays. The default presets overrides many of the manual settings or multiplies their effect with no onscreen indication they are engaged -- other than "unintended" signal degradation.

The presets for the DVI connector are different than the presets for the HDMI connector, because it is assumed when using the DVI connector a full resolution signal with no need for sharpening and color correction will be input.

The presets for the HDMI connector are different than the presets for the DVI connector, because it is  assumed when using the HDMI connector a low resolution signal with need for sharpening and color correction will be input.

The end result is if  the presets are not changed or disabled, when moving a computer video signal from the DVI connector to the HDMI connector, the signal will be -
  • [incorrectly] sharpened [generating a "false" alias pattern - commonly called a "Halo distortion"]  around Text
  • [incorrectly] color corrected [generating a "false" color image - commonly called "Hue distortion"] over Dialog boxes
In the gaming community this is commonly called the "Samsung Effect" to quite a bit of amusement. It is considered a right of passage for "Noobs" to figure out. Then understand the directions to disable the preset for the HDMI input. The procedure remains an exercise of discovery on other vendors products.

Basically to disable the HDMI preset and restore the computer video signal, the Remote must be used to -

enter the [OSD] main menu
enter the [Inputs] sub menu
enter the [Edit Name] sub menu, by scrolling below the [Source List] sub menu
enter the [HDMI] sub menu, by scrolling below the [PC][DVI][AV][Component] sub menus
select the [PC] or [DVI PC] [>-preset-<] from the possible choices listed below:

----
VCR
DVD
Cable STB
Satellite STB
PVR STB
AV Receiver
Game
Camcorder
PC
DVI PC
DVI
TV
IPTV
Blu-ray
HD DVD
DMA

The default '----' and all but the [PC] or [DVI PC] profile will impose a starting preset which will be applied and added to the base settings of the manual controls.. reducing and defeating their purpose.

Because of the seeming "conflict" with reason and personal opinion, many assume this right of passage to be a hazing attempt or 'practical joke'. Unfortunately it is not.

Also, while performing the steps to achieve a visual outcome, there is no feedback from the system to indicate a change has occurred to the presets, until the final step is executed to confirm the "Name Change" even though the "Edit Name" menu is not actually used to "Change Names" but is in reality a "baseline preset" tool.

While scrolling through the presets called "Names" the video signal will not visually begin changing back to its unmolested form, until either the [PC] or the [DVI PC] preset is highlighted -- the appearance of the signal on the video monitor will visually "Snap" into perfect clarity and color gamut.

I have no means to access and compare these "presets" to be sure, but it appears only the [PC] and [DVI PC] are appropriate for computer HDMI signal inputs, the rest are so distorted as to make human comparisons unreliable.

There are "many" forums and blog postings suggesting reducing resolution, using different cables, swapping video cards, adjusting brightness and contrast, even reducing "sharpness" -- none of these will defeat the built-in presets, it is presumed a good deal of expense has been rendered by "Noobs" attempting to resolve this problem.

This is one procedure when moving from using DVI to HDMI connectors on your LCD monitor you should look for, in particular for Samsung LCD monitors and also on many other vendors LCD monitors they are known to be excrusiatingly obtuse and arcane to debug. Which is one reason Samsung LCD monitors are held in high regards.. because the procedure is fairly well known to the indoctrinated.

It remains unfortunately an "urban legend" which has proved to be true.

Uber HDMI cables and settings can build upon the performance of the original equipment only once its unmolested signal is actually being displayed and not overtly "corrected".