jerry davis
Auditioning
- Joined
- Oct 30, 2002
- Messages
- 14
If a dvd is 480p, what is the quality of a laser disc?
It's the same number for all NTSC sourcesActually it's 525 when they become NTSC. Most sources that make DVD titles (D1, DigiBeta, and D5) have 486 lines of active picture, not 480. MPEG-2 throws six lines away to make macroblock rounding easier
Some formats like VCD and SIF res MPEG 2 (DVD compliant) store far less than 480 lines, generally half at 240-288 lines. They eventually get blown up to RS-170 standards when they get displayed on analog television sets.
Just read your link to the FAQ... I love JT, but he's got to go through that FAQ and change some stuff. No consumer set has 480-483 "visible" lines of resolution. Overscan makes sure of that. DVD has 480 lines of active resolution in the MPEG stream, but they are not visible on your sets. I also question his arrival at the 540 H-res for DVD. Anyone care to explain that math? Doesn't pan out for me. Also he does not address signal to noise ratio or chroma vs. luma resolution when comparing formats. Etc. etc. done...
Actually it's 525 when they become NTSC.Aw, c'mon, Morgan, I did say "visible".
M.
So while the video quality is better with anamaphoric dvd, with laserdisc I can watch the Star Wars and Indiana Jones trilogies in their original aspect ratio whenever I want.And in their original unaltered versions too! God forbid what Indiana Jones will look like once the mangled version is released on DVD...
Thanks guys. Laser disc quality is not very good is it?Actually it is.
I also question his arrival at the 540 H-res for DVD. Anyone care to explain that math? Doesn't pan out for me.As you command. Just apply the common 'circle rule'. The horizontal resolution (TVL) is defined as the amount of horizontal pixels/samples with the width of the biggest 'circle' (not elipsoid) that you can fit within the frame at its intended aspect ratio.
Thus if you have a DVD encoded for 4:3 aspect ratio, you take the 720 horizontal pixels encoded on the DVD and devide it by (4:3).
720 / (4 / 3) = 540.
Thus 540 horizontal pixels in the biggest 1:1 square (or circle) that fits in the frame.
In the case of an anamorphic 16:9 DVD, its:
720 / (16 / 9) = 405.
The unintuive odd fact that the 16:9 number is lower demonstrates nicely, that TVL is kinda awkward and confusing and shouldn't really be used anymore in our digial age. Just define the resolution and aspect ratio of the frame and be done with it.
And leave out timing, not to confuse the matter even more
Regards
Bjoern
if you can help me what are some "decent" players at good prices I can get on ebayYou'll probably get more answers if you ask this in one of the hardware forums, notably Audio/Video Sources. But before you ask, do a search; there are many existing threads discussing the pros and cons of various LD players.
M.