View Full Version : Resolution of DVDs
carrott_girl
05-01-2002, 16:42
Right, my brother is a crazy loony and wants to know what the resolution of a DVD is? Now, sweet cream on an ice-cream sandwich, what in the blue hell is he going on about? Please help.
(sorry if in wrong forums). :)
don't think they have a resolution, in the traditional computer monitor terms of number x number - the picture is made up of lines.
PAL images have 625 lines and NTSC 525 lines, I'm sure someone will be along to correct me soon enough if I'm wrong :)
Originally posted by carrott_girl
Now, sweet cream on an ice-cream sandwich.
:clap: LOL. That's my new saying of the week. Fantastic.:D
Better in the DVD and Movie Forum I think :)
Joe Pasquale
05-01-2002, 17:29
Um, I'm pretty sure it's:
PAL - 720x576
NTSC - 720x480
The Wicker Man
05-01-2002, 17:35
Originally posted by Joe Pasquale
Um, I'm pretty sure it's:
PAL - 720x576
NTSC - 720x480
Yup, c'est bon...the numbers are the number of picture elements (in the x and y directions) that make up the full picture. So the total number of picture elements will be 720 multiplied by 576 - work it out for yrself.
Also, PAL works at 25 frames per second (25 different pictures are shown in one second which you or I see as a 'moving' image). NTSC works at 30 frames per second, and I've got a feeling film projectors work at 23.9 frames per second (or is it 29?)...
Why do I know this?? I don't want to know this, it's pointless!
EDIT - ooo, Joe, I like your sig. singing the little fella's tune as I type...:)
Joe Pasquale
05-01-2002, 17:40
Originally posted by The Wicker Man
EDIT - ooo, Joe, I like your sig. singing the little fella's tune as I type...:)
Cheers, I had to retire it a while ago cos I was told it was too big (only widthways! :nuts: ) ... Still is over the limit now, but it looks crap any smaller. :)
richie99
05-01-2002, 18:50
I've just done a bit of research, and if you mean picture resolution measured in lines (i.e. PAL TV is 625 lines), then
DVD is between 480-500 lines.
Just for comparison, good old VHS can only manage 240 !
The Wicker Man
05-01-2002, 19:22
Originally posted by richie99
I've just done a bit of research, and if you mean picture resolution measured in lines (i.e. PAL TV is 625 lines), then
DVD is between 480-500 lines.
Just for comparison, good old VHS can only manage 240 ! That's really talking about TV screen resolution then though, which, although relavent, is a little off the point.
see http://www.vcdhelp.com/xvcd.htm#comp for some info. If you say PAL DVD is 720x576, that should mean there are 720 picture elements across the screen, and 576 lines (or vertical picture elements). You'll notice that the DVD line no. is less than the number of lines on a TV...I'm pretty sure this is to do with giving the TV time to scan back up to the top of the screen between frames (the TV image is formed by scanning the screen from top to bottom with an electron beam). Of course, this is made even more complicated by interlacing - any one tv frame is displayed on your TV in two halfs, each displaying alternating lines to make up the full image (this is done for bandwidth reasons).
720x576 = 414720 picture elements in total.
[For comparison, when you talk about digital cameras, say, you here resoutions quoted in terms of megapixels - this is just the total number of picture elements that make up one picture. For some reason, video is quoted in terms of 'x by y' resolutions, but digi cameras resolution is quoted in terms of the total pixel number]
Above is badly written - soz if it doesn't make sense or is wrong!
richie99
05-01-2002, 19:59
Whoa there pal...!
Things are getting a little too technical here - I think carrott_girl just wanted a layman's answer, but hey, you certainly know your onions.
:D
<B>You'll notice that the DVD line no. is less than the number of lines on a TV...I'm pretty sure this is to do with giving the TV time to scan back up to the top of the screen between frames</B>
Yes the number of <I>active</I> lines is 576 the others are used as you say for flyback and sync, also teletext on analogue transmissions.
I think they use the number of pixels on digitla camera as a comparison between cameras only as when taking pictures you can set the resolution to higher or lower. Higher interpolation I don't know why (it could be done after) on a computer, lower to get a larger number of pictures in the memory without very apparent compression artifacts.
carrott_girl
05-01-2002, 20:50
Originally posted by richie99
Whoa there pal...!
Things are getting a little too technical here - I think carrott_girl just wanted a layman's answer, but hey, you certainly know your onions.
:D
You calling me stooopid? ;)
Thanks people, my bro knows what you're all jabbering on about so it's sorted. :)
The Wicker Man
05-01-2002, 21:43
If I may ask, whyzhe wanna know??? WHY WHY WHY??? :D
What is the visable resolution in 2.35:1 versus 16:9 versus 4:3? 720 by what?:D
playaslaya
06-01-2002, 19:10
Originally posted by carrott_girl
Now, sweet cream on an ice-cream sandwich, what in the blue hell is he going on about? :)
Oh you like to Copa? Copa your a$$ out of here Jabroni!!!
;)
Originally posted by erw
What is the visable resolution in 2.35:1 versus 16:9 versus 4:3? 720 by what?:D
If it is anarmorphic then it will be the same, if it is isn't then:
2.35:1 = 1:0.43
16:9 = 1:0.56
4:3 = 1:0.75
Therefore, vertical resolution=
for 2.35:1 = 576 * 0.43/0.75 = 330 pixels
for 16:9 = 576 * 0.56/0.75 = 430 pixels
DeadKenny
07-01-2002, 01:00
Various bits on DVD specs at the following...
http://www.dvddemystified.com/dvdfaq.html#3.4
http://www.dvd-video.co.uk/
Main thing to know is that firstly, neither PAL or NTSC formats are actually stored on the disc and secondly the resolution options are as follows...
MPEG-2, 525/60 (NTSC): 720x480, 704x480, 352x480
MPEG-2, 625/50 (PAL): 720x576, 704x576, 352x576
MPEG-1, 525/60 (NTSC): 352x240
MPEG-1, 625/50 (PAL): 352x288
Though usually DVDs are MPEG-2 format and are either 720x480 or 720x576.
It's a purely digital format (unlike VHS and laserdisc) though usually stored interlaced (but can be stored progressive as well) and colour encodings such as PAL, NTSC, SECAM are irrelevant (the player will convert accordingly, but if you use RGB output or play on a computer monitor it doesn't need to).
DVDs for NTSC markets tend to be stored in either 24fps or 30fps (former for films, latter for TV), and those for PAL markets are normally 25fps regardless of film or TV (the former being sped up by 1fps).
24fps discs usually have 3:2 pulldown (http://www.dvdfile.com/news/special_report/production_a_z/3_2_pulldown.htm) applied to the output (by the player) for playback on 60Hz displays (i.e. NTSC) because 24fps doesn't go easily into 30fps for 60Hz. 30fps discs obviously just get shown at 60Hz and 25fps at 50Hz.
Bapapapa
07-01-2002, 01:48
http://www.cs.tut.fi/~leopold/Ld/ResolutionComparison/
Originally posted by carrott_girl
sweet cream on an ice-cream sandwich, what in the blue hell is he going on about?
If you smell
what the carrott
is
cooking
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