what to do with signal lines at bottom of vhs caprture...

[bdub]

i hope this is the right forum...
i have some old footage that i captured from vhs to mpeg-2 (720/480). i am cutting clips of it to avi (divx) 640/480. my question is what should i do with the few lines at the bottom of the screen that contain signal from the tape, but don't have any info for the real picture. can i crop those lines and resize the mpeg-2 to 640/480, and keep the 640/480 resolution, effectively enlogating top to bottom, and have it look true? or does this make the video stretch and not be true to the original (therefore using 640/475)? i want to keep the original signal intact without making subjects look skinnier than they are, but i'd also like to lose those lines, if possible.
i'm using "vdub for mpeg2" (1619) to deinterlace and resize and uncompress. then using vdub190 to compress to divx, and this is where i'm not sure if cutting off those lines and resizing would make things look wrong, or correct it.
thanks.

[Guest]

As long as you cut a corresponding portion of the width, then you can do it while retaining the correct aspect ratio.

[bdub]

so those lines figure in the actual size top to bottom... thanks, that's what i needed to know. i don't want to cut the width, so the lines stay. i guess those lines would normally only be seen in the overscan area on a normal tv?
there's a guide for all this right? can anyone point me to that?

[Guest]

How many lines are affected. If it's not too many, you can make them less noticeable with BorderControl().

[bdub]

5 - 7 lines depending which side of the 640/480 frame i'm looking at. i may look into fixing some of this in the future, but for the rough web ready clips i'm making now, the lines will be fine as long as i know the aspect ratio is correct with them in. thanks.
is there a good guide that tells about the functions of those lines and how the overscan area works and all that?

[Guest]

It's head switching noise. It doesn't have a function.

Overscan applies only to CRT TVs, which scan an electron beam.

IMHO, leaving that noise is low-class and will mark you as a dilettante.

[smok3]

you could (assuming the target has square pixels);

a. crop 16 pixels at the bottom and encode at
640x464
(width resize)

b. assume that active-scan area is about 10% smaller than full frame and just use that, circa:
# resizeCalc Avisynth
# pixels = 272384, DAR error = 0.585
# Crop(Left, top, -right, -Bottom)
Crop(20,10,-20,-22) # 680(-8px)x448
LanczosResize(608,448) # (modw16,modh16)
http://resizecalc.somestuff.org/index.php?ssmw=720&sar=0.888889&sar2=&ssmh=480&CT=10&CL=20&CR=20&CB=22&mplayCrop=&trw=608&dar=1&dar2=&modw=16&modh=16&padw=&padh=&css=&doit=true
(width resized, no height resizing)

c. play around to get the smallest DAR error
# resizeCalc Avisynth
# pixels = 262656, DAR error = 0.188
# Crop(Left, top, -right, -Bottom)
Crop(6,10,-6,-22) # 708(4px)x448
LanczosResize(608,432) # (modw16,modh16)
http://resizecalc.somestuff.org/index.php?ssmw=720&sar=0.888889&sar2=&ssmh=480&CT=10&CL=6&CR=6&CB=22&mplayCrop=&trw=608&dar=1&dar2=&modw=16&modh=16&padw=&padh=&css=&doit=true
(width and height resized)

d. letterbox the smeary part with black and encode at 640x480.
(width resize)

[bdub]

thanks, i like option d. appreciate the help, guys. I cropped 6 lines and letterboxed, so a little black at the top and bottom.

[movmasty]

i hope this is the right forum...
i have some old footage that i captured from vhs to mpeg-2 (720/480). i am cutting clips of it to avi (divx) 640/480. my question is what should i do with the few lines at the bottom of the screen that contain signal from the tape, but don't have any info for the real picture. can i crop those lines and resize the mpeg-2 to 640/480, and keep the 640/480 resolution, effectively enlogating top to bottom, and have it look true? or does this make the video stretch and not be true to the original (therefore using 640/475)? i want to keep the original signal intact without making subjects look skinnier than they are, but i'd also like to lose those lines, if possible.
i'm using "vdub for mpeg2" (1619) to deinterlace and resize and uncompress. then using vdub190 to compress to divx, and this is where i'm not sure if cutting off those lines and resizing would make things look wrong, or correct it.
thanks.
first of all you should capture at 704x480 to have correct aspect at 640x480

still better to capture directly at 640x480

[Wilbert]

first of all you should capture at 704x480
It doesn't matter whether you cap at 720x480 or 704x480, you will capture the same image. Whether resizing to 640x480 is correct depends on the capture window of your capture card. The analog capture guide explains that in all detail.