Video Asylum

Posted by Joe Murphy Jr (A) on May 01, 2002 at 19:25:25

In Reply to: Re: Any 12-bit / 108MHz DVD Players ? posted by Homer on April 30, 2002 at 22:02:07:

CD is only 16-bit -- we've used 18, 20 and 24-bit DACS to process the data. Based on your info, we don't need anything higher than 17 bits. I don't think anyone uses less than 20-bit DACs today.

Increasing the sample rate is not to cut corners on the filter. It's to allow the use of a filter that operates farther away from the range of the desired signal. Filters have detrimental effects -- operating at a higher frequency decreases those effects. In the audio world, Pioneer had a DAT player that was only 16-bit, but it sampled as high as 96kHz. When the 44.1, 48 and 96kHz recordings were compared, the 96kHz recording sounded smoother (aka "better"). Same amount of bits used to record, but less "filter" effect. The company dCS has published many articles about sample rates and filter interaction. For whatever reason (technical or otherwise -- maybe voodoo), higher sample rates sound better. I should add that we're talking equal quality here -- don't compare "Everything for $1" with "Tiffany's".

Many players also use higher sample rate video DACs because they upsample part of the video signal (can't remember which part right now). The component video is recorded at 4:4:2, but some players upsample that 2 to a 4 -- making the signal 4:4:4 instead. I can't remember the exact reason for this (something about signal delays, I believe), but it's said to make the picture better/smoother/more "film-like".

As far as digital video goes, for $1000 you can get the mod done to your DVD player right now. There are 2 companies that do this mod (grabbing the digital component signal from the DVD before it's converted to analog) which allows a direct digital connection to a display capable of accepting this signal. I believe some plasma displays have this capability. Granted, it's not "on the street", but it's available. And no, the studios most definitely don't want you to have it.

For what it's worth, the new hi-end DVD players (Denon, et al) use 14-bit/108 MHz video DACs. The Ayre DVD player used a 14-bit video DAC in last year's model, but I believe it was only (!) a 54MHz DAC. I also believe last year's Camelot DVD player use a 14-bit video DAC (but don't quote me on that one).