dv to dvd with resize - what about interlace ?

[thoralf]

Hi there,

just a quick question I cannot answer myself (despite having searched the forum):

I want to convert footage from a mini dv cam to mpeg2 that will finally be going onto a dvd. now, I have to crop the footage, since there are black borders around it. Having learned the hard way that de-interlacing dv footage converted to mpeg2 results in a really bad picture on tv sets, I am pondering about the right way of doing this ...
I figure that any cropping and resizing on interlaced footage will mess up the interlacing quite badly, so am I forced to de-interlace? Do I have to treat even and odd frames separately?

thank you for your help,
thoralf.

[communist]

Having learned the hard way that de-interlacing dv footage converted to mpeg2 results in a really bad picture on tv sets, I am pondering about the right way of doing this ...
Thats not really correct - I guess what you mean is that "usual" home mini DV footage looks jerky.
Anyway since you plan on creating a DVD for viewing on TV I would keep it ALL as it currently is.
The black bars you seen on your PC wont be seen TV due to overscan. If you crop them away so that the entire picture is filled with "real picture" then you will 'loose' even more of the original picture when watching it on TV.

If you still need to do it for whatever reasons this would be a way to do in AviSynth:
AviSource("yoursource.avi")
Crop(you crop values here)
SeparateFields()
LanczosResize(720,288) # or any other resizer, these values are for PAL footage
Weave()

[thoralf]

thank you communist,

I didn't think about the tv overscan ... the footage was actually recorded from the s-vhs output of a graphics card (well, actually, with a video mixer inbetween).
leaving everything as-is saves me from alot of trouble. how does tmpgenc fare with the black borders, then?


SeparateFields()
LanczosResize(720,288) # or any other resizer, these values are for PAL footage
Weave()
nifty.

with kind regards,
thoralf.

[bb]

You may use Letterbox or Crop / AddBorders to get clean black borders that compress better than the captured borders.

bb

[scharfis_brain]

@communist: this resizing method is not recommened, cause it introduces vertical misalginment of the fields. also interlaced scaling should be avoided by every cost.
It just introduces too much blurryness.

you should go the way bb described.

[communist]

Thanks didn know that - but as you said I have so far avoided it all. I either deinterlace or encode as interlaced and in case of DV -> DV (for transfer back to tape) I keep it always interlaced.