FULL-mode lock is a behavior exhibited by certain widescreen displays, in which any signal sent to the progressive inputs is interpreted as having the native screen aspect ratio of 1.78:1. The incoming signal will be displayed as a 1.78:1 rectangle, regardless of what its original aspect ratio was, and no direct user overriding of this behavior is permitted. This poses problems if the source material is not 16x9-enhanced, because most DVD players will not reformat it to properly render on 1.78:1 screens, and it will appear as stretched and distorted. Because many DVD titles are formatted as 4:3 or non-enhanced letterboxed, this has caused no small amount of grief for owners of FULL-mode lock widescreen displays. Although the sets in question are usually equipped with interlaced (non-progressive) inputs that do allow reformatting, in many cases the reformatting is implemented poorly, and the results are visibly inferior.
For years, frustrated owners have been led to believe that there are only workarounds to these problem, not real solutions. This, however, is not true, and largely stems from misconceptions as to what FULL mode actually is. Articles on DVD and widescreen TVs in the popular press refer to FULL mode as "anamorphic" mode, a mode where inputs are "stretched" by the set 33%. That, however, is inaccurate. FULL mode "stretches" the progressive signals emitted by most set-top DVD players only because these machines output them formatted as 4:3 instead of the native 1.78:1 of the display. This little-known fact is the key to unlocking the potential of the DVD/HD-ready display combination.
Note: The techniques described in this article are applicable to widescreen displays in general, and offer the potential for substantial image improvement for FULL-mode lock and non-FULL-mode lock sets alike.
To illustrate typical formatting problems with FULL-mode lock, two pairs of sample images are provided. The first sample is of non-enhanced letterboxed widescreen, while the second is of standard 1.33:1 full-frame.
The first set consists of two renderings of the same frame of Viva Las Vegas, a 2.35:1 non-enhanced letterboxed offering from MGM. They demonstrate the difference between letterboxed widescreen properly formatted for 1.78:1, and the distorted rendering resulting from use of a typical progressive-scan set-top DVD player with a FULL-mode lock display. Note how the first image is in its proper proportions, with black bars on the top and bottom occupying the unused screen space, while the second image is distorted due to being "stretched" horizontally by 33% without an corresponding "stretch" in the vertical axis.
|Viva Las Vegas appears courtesy of MGM|
|2.35:1 letterboxed properly formatted for 1.78:1|
|Non-enhanced 2.35:1 letterboxed improperly formatted for 1.78:1 due to FULL-mode lock|
The second set consists of two renderings of the same frame of The Night Stalker, a 1.33:1 full-frame offering from Anchor Bay Entertainment. They demonstrate the difference between 1.33:1 (the standard TV screen format) properly formatted for 1.78:1, and a FULL-mode lock rendering. Note how the first rendering is in its proper proportions, with black bars on either side occupying the unused screen space, while the second improperly fills the screen because it is horizontally "stretched" by 33%.
|The Night Stalker appears courtesy of Anchor Bay Entertainment|
|Standard 1.33:1 properly formatted for 1.78:1|
|Standard 1.33:1 improperly formatted for 1.78:1 due to FULL-mode lock|
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