What is the correct way to figure resolution?

[thebach]

What is the correct way to figure resolution? I know you can't just take off the same number from 740x480, so how do you figure resolution if you want to resize something, I tried fitcd and it looks like a nightmare

[Vejita-sama]

??? I'm not sure what you're asking or trying to do? Here's some basics that might help:

DVD - 720x480, 352x480, 352x240
VCD – 352x240
SVCD 480x480
CVD – 352x480

However you can make an x(S)VCD at any resolution. But if you want it to play on your standalone you should stick to 720/480/352 x 480/240. Hope this helps some.

[thebach]

I mean if your trying to size down a little to correct overscan on my tv. I've been reading through a search on it but still don't see the answer. Can you just take multiples of 16 off the 720x480? In other words take 32 off the 720 and 32 off the 480 to give 688x448? Then encode to 720x480 in tmpg with aspect to center. Or will this distort the image? I didn't think you could take the same amount off the vertical and horizontal

[puertorican138]

I mean if your trying to size down a little to correct overscan on my tv. I've been reading through a search on it but still don't see the answer. Can you just take multiples of 16 off the 720x480? In other words take 32 off the 720 and 32 off the 480 to give 688x448? Then encode to 720x480 in tmpg with aspect to center. Or will this distort the image? I didn't think you could take the same amount off the vertical and horizontal

Yes, you can resize the video to make it fit your T.V without any of the edges cut out (overscaning). :P

[mbm]

I use the that technique to correct for overscan on my TV, and it works great for me. I cap at 688x448 then resize to 720x480 w/centered alignment. I actually think that it helps increase the quality of the final encode because there is about 10% less motion area that the encoder has to deal with so it can redistribute those bits to the viewable part of the frame.

[thebach]

so you can take increments of 16 off both horizontal and vertical without distortion problems? I didn't think you could

[mbm]

Technically you are correct that the aspect ratio is skewed by taking off equal amounts in both axis. To maintain the aspect ratio it would have to be 672x448, but on my TV, I start to see the borders on either side of the screen. To remove that visible border I go with 688x448. The change in aspect ratio from 1.5 to 1.535 is hardly noticeable.

[thebach]

So is there some formula to use when figuring aspect ratios?

[Anonymous65]

To capture all of the video information in NTSC video, you capture all the video. If the video is only goinf to be played on a PC screen, meaning there will be no overscanning, then you can *crop* the fully captured video to cover the video head wsitching and other artifacts found at the edges of the full screen video frame. If you for some strange reason I don't understand, only want parts of the video frame, then capture less than full video details.
Video, displayed on a TV set or a PC monitor, always have a aspect ratio of 4:3 (4 units wide, and 3 units high). But, since the digital NTSC D1 standard is based on rectangular pixels, and not square pixes used on computers, there are some differences between between the pixel resolutions. Full screen video on a computer is 640x480. Full screen video on a TV set is 720x480. Both have an aspect ratio of 4:3.
If, for some strange reason you want the video look the same as it does on a PC monitor, meaning you don't want any overscan, you will have to make a guess on how much overscan *your* TV has. Every TV has a different amount of overscan, so it's impossible to make a "full" screen video on all TV sets. The only thing you can do is to add black borders around your video that will show up on some TV sets depending on how much the overscan is. However, on some monitors and TV's you will see an (ugly) black border, which in the TV industry is seen as a problem (too much blanking).
So, if you want to produce *correct* professional video, you capture at full resolution, and encode all the video with no cropping or black borders.
As a video editor or producer, you should know what overscan safe area is, and take that into account when producing video.

[DJRumpy]

The formula your looking for is ((H * 9) / 16 ) for 16:9 movies, or (( H * 3) / 4 ) for 4:3 movies, where H = Horizontal Resolution (NOT height)

If you resize your video to 672, and it's a 4:3 movie, then plugging 672 into H above, yeilds ( (672*3) / 4 ) = 504, your so movies resolution should be 672x504 to maintain a 4:3 aspect ratio.

If your movie was 16:9, your do the following:

((672*9) / 16 ) = 378 (or 672x378 )

If you working with aspect ratios, like 1.85, or 2.35, then you simply divide the horizontal resolution by that number ( 672/2.35 = 286 rounded ). Many suggest you stick with multiples of 16, even if it means skewing your aspect ratio a tad, so it's up to you as to what numbers you plug in. The reason has something to do with the way lossy codecs compress the data. They say if it's not a multiple of 16, the quality can degrade. Someone may have more info on this.