This is one of the only known discs to be encoded in the QX format. The QX format was supposed to be the S-VHS or ED Beta of the VHD format, increasing the effective resolution of the VHD format from 250 horizontal TV lines to 430 horizontal TV lines. Unlike S-VHS or ED Beta, QX featured full backwards compatibility with older, standard VHD players. On non-QX players, the standard 250 horizontal TV lines will be correctly resolved with only slight additional noise in areas with high frequency information. The only two VHD players able to play back QX discs at full resolution are the Victor HD-V1 & the National DP-870.
This disc contains selected segments from Green Horizon (available as a promo-only, standard VHD: [CUHA-12640] ) along with a test signal. The test signal, when played back on a Victor HD-V1, does resolve a full 430 TV lines of resolution while even a Victor HD-9500 will only resolve around ~250 lines with the exact same disc. Unfortunately, the video content itself does not appear to take advantage of the the full 430 lines possible from the format.
Of particular interest is the jacket which has a couple glued pieces of printed paper on the front and back. The front provides instructions on how to demonstrate the disc. It also discusses how to respond to the enviable "What about Laserdisc?" question. The rear paper indicates that this disc was intended for sales demonstration and to show that VHD is competitive with Laserdisc (and other Laserdisc competitors like S-VHS & ED Beta) and provides a list of 5 very specific instructions when showing the disc.
The front paper instructions on proper disc use approximately translate to the following:
- You can demonstrate the high resolution with either two or one high-resolution (500 TV line) TVs. With one TV, use a single Victor HD-V1 player with a QX disc and turn the sharpness knob all the way up to show the full 430 TV line resolution. Turn all the way down to demonstrate standard 250 TV line playback. With two TVs, use two Victor HD-V1 players. Put the QX disc in one player and non-QX-encoded Green Horizon disc in the other. Play from frame 3000. Quality will only be slightly more \"stereoscopic\" on the QX disc due to the noise of the master tape but explain to the client that the QX disc looks more beautiful.
- You can demonstrate backwards compatibility by supplying a Victor HD-V1 player and Victor HD-9500 player. When the QX disc is placed into the HD-V1, it will resolve 430 TV lines on the test pattern but on the HD-9500, it will only resolve 250 TV lines. When the normal Green Horizons disc (w/o test pattern) is put into the Victor HD-V1, it will resolve 250 lines but due to enhanced cutting methods it will look like almost 400 TV lines. The HD-9500 will resolve just as many lines.
- You can provide an over-the-counter demo. Never use test patterns from the VRG-1460 disc. The HD-V1 has a circuit design that improves visual resolution over the HD-9500 even with normal discs (put sharpness knob at center position). The visual resolution is better due to improved cutting material that reduces noise and crosstalk. The visual resolution is just about 400 TV lines. Some say it looks better than LDs in resolution.
The front notes also that Laserdisc players have a resolution of about 425 lines but the signal on current production Laserdiscs is around 300 lines like a standard VHD. A master tape has to go through two or more dubs before the final pressing which reduces the 5MHz master resolution (approx. 400 TV lines) in half due to accumulated noise. Once a better intermediate format such as S-VHS starts increasing in use, QX discs begin to be produced. However, since current master tape quality is so limited, no QX-encoded software will be released for the time being.
These rear paper instructions roughly translate to the following:
- For demonstration to Victor dealers only. Show only with managers present. Do not give over-the counter demonstrations.
- Do not leave disc with Victor dealers.
- Do not show (particularly the test patterns) to Laserdisc dealers, newspapers, nor magazines.
- Do not play or compare disc side-by-side to an S-VHS test pattern.
- Will not play correctly on older players like the Victor HD-7500 or HD-7900.