512 X 384 resized to 640 X 480...any loss in quality?

[90sTV]

Lately, I've encountered SD video captures that are in 512 X 384, and with my VLC player set to play them at native resolution, the video is smaller than it is for stuff that plays at 640 X 480. I'm guessing that the whole 512 X 384 idea comes from some sort of calculation that says 384 is enough to capture all vertical detail, and they then set the horizontal to 512 just to keep the 4:3 aspect ratio? If I resize it to 640 X 480, does that cause a loss of video quality through scaling? I'm not great at judging what is more "accurate."

I see in the video help section that the recommendation was 352 X 480 for SD analogue broadcast captures.

[pandy]

Lately, I've encountered SD video captures that are in 512 X 384, and with my VLC player set to play them at native resolution, the video is smaller than it is for stuff that plays at 640 X 480. I'm guessing that the whole 512 X 384 idea comes from some sort of calculation that says 384 is enough to capture all vertical detail, and they then set the horizontal to 512 just to keep the 4:3 aspect ratio? If I resize it to 640 X 480, does that cause a loss of video quality through scaling? I'm not great at judging what is more "accurate."

I see in the video help section that the recommendation was 352 X 480 for SD analogue broadcast captures.

This is very large topic so to be short - if you really must re-size source video go with some even factor if even is not possible then odd factor may be acceptable however try to avoid fractional factors - in other words enlarge your video by 2 - from your perspective perhaps resize on display without resizing source will be ok? configure your player in a way that video is rescaled on the fly whenever played .

[JVRaines]

I'm guessing that the whole 512 X 384 idea comes from some sort of calculation that says 384 is enough to capture all vertical detail, and they then set the horizontal to 512 just to keep the 4:3 aspect ratio?

That's incorrect. NTSC has 485 and PAL 575 lines of visible vertical resolution in the analog standards. Converted digital video employs 480 and 576 lines, respectively, to simplify binary arithmetic operations.

[jagabo]

Any time you scale a video you lose quality.

Any time you reencode a video with a lossy codec you lose quality.

Of course, depending on how you do it the loss may not be very visible.

512x384 is just an arbitrary 4:3 frame size. Someone may have used a program that uses a compromise of frame size vs. file size.