mark_vints Posted January 23, 2001 Share Posted January 23, 2001 ... or to put the question in the reverse sense: when capturing a 480x640 pixel image of a video frame onto my computer, do I capture all information present in the image? Link to comment Share on other sites More sharing options...
peter_mclennan Posted March 30, 2001 Share Posted March 30, 2001 Yes. 640X480 is about the limit of res for a video grab. And that's if you can grab a progressive scan frame. Grabbing a frame of Interlaced video will give you 640X480, but each of the two fields of video are recorded 1/30th of a second apart, leading to weird artifacts. See my website for examples of what progressive scan video grabs look like www.vfs.com/~peterPeter McLennan Link to comment Share on other sites More sharing options...
asc135 Posted January 3, 2002 Share Posted January 3, 2002 Short anwswer: No. First, it is usually 640 pixels left to right and 480 pixels top to bottom. So the number you are trying to relate would be the 640, not the 480. Second, lines are a measure of the ability to distinguish closely spaced lines drawn from top to bottom, stacked left to right. The more lines you can cram across the screen and still distinguish as unique, the higher the video resolution. But remember that each line has to have space before the next line in order to be able to distinguish it. Therefore, pixels can't correspond exactly to lines. A crude conversion I've seen used is a ratio of ~1.4 pixels per line. So a 640x480 image would have similar resolution as a video signal of about 450 lines. This is much more than either 8mm/VHS (240) or broadcast TV (330). Hi8/S-VHS is about 400. D8/DV is about 500. Link to comment Share on other sites More sharing options...
mark_postma Posted March 20, 2003 Share Posted March 20, 2003 And then you have to look at the television capabilities. Most televisions display 'around' 640x480 viewable and can cut a little bit off of the top and sides as well. 640x480 is considered (generally) what is viewd on the tv screen, though. Link to comment Share on other sites More sharing options...
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