Selecting the right picture aspect/format for 1:1 pixel mapping

[Richard]

Blu-ray calibration disc

If you have a blu-ray player then for about $20 you can buy a calibration disc and not only figure out what the right aspect or format is for your HDTV but also learn how to determine performance, make other adjustments to improve picture or sound and have some quality material to test your system.

Digital Video Essentials: HD Basics, on blu-ray is highly recommended.

Best results come with using the 1080p output setting from your player and this method only works with a 1080p display. Using the SMPTE 133 pattern you have achieved 1:1 pixel mapping when the aspect setting provides the most clear response for both the vertical and horizontal boxes of fine lines in the center of this test pattern and none of the corner boxes are clipped proving you have zero overscan.

Plasma users will need to turn off any picture mode that causes the image to orbit to get this result. Turning off this feature may make your plasma more susceptible to image retention or burn in.

PC

Set the PC for 1080p output, specifically 1920x1080 for a 1080p consumer HD display.

Using the desktop graphics you have achieved 1:1 pixel mapping when the aspect setting provides the most clear response for text and none of the icons on the side or the bottom bar is clipped proving you have zero overscan.

Plasma users will need to turn off any picture mode that causes the image to orbit to get this result. Turning off this feature may make your plasma more susceptible to image retention or burn in.

If you have a 1080p PC monitor this should all happen automatically and you will likely lose any format or aspect options if even available; if needed the correct output setting would be 1920x1200.

Educated Guessing

Make sure your source is set for a 1080i output with HD content.

Amongst all your choices there are only one or two that are correct and most owners manuals do a good job of pointing out how these different options affect the original image. The one or two options you are looking for are those that change nothing from the original your are receiving. A great starting point is to tune in a local station that is known to broadcast SD content correctly on their HD signal leaving black or gray bars on the left and right sides. If that is your result and your display is not a flat panel you are done.

PITFALLS: Cable boxes and satellite receivers have their own aspect and formatting options along with scan rate settings like 720p and 1080i which must also be set properly for 1:1 pixel mapping. Some DVD players and blu-ray players may have format / aspect options as well. Use 1080p for your 1080p display when ever possible or 1080i when not available.

If you have a flat panel you will also have two aspect or format options that appear to be exactly the same on the surface except for one small difference; one applies some overscan and the other does not. When viewing HD content you may not note any difference except that one appears sharper and more detailed than the other; the sharper version is your 1:1 pixel mapping. When viewing SD content you may notice a thin line of black top or bottom and depending on the channel you may even see the VIR information for NTSC appearing as flashing white dashes at the top edge. If you see this you have achieved 1:1 pixel mapping. Most viewers find the VIR signal irritating and for some that includes the thin black lines which is why manufacturers include the other aspect that applies some overscan to hide this. To prevent complaints the product is preset by the manufacturer to use the aspect or format that provides some overscan.

Plasma users will need to turn off any picture mode that causes the image to orbit to get this result. Turning off this feature may make your plasma more susceptible to image retention or burn in.

PITFALLS: Once the transition to DTV is complete for 2009 the VIR signal should die along with NTSC in which case the white dashes will be gone. Not all SD content on an HD signal will have thin black lines top and bottom.