Confused about deinterlacing

[Just_Cindy]

what is the sense of capturing above 352x240, only to deinterlace during conversion?

don't we lose a field during deinterlacing thus leaving only one field?

i need help with this because when ever i capture above 352x240 i have to deinterlace and it doesn't look any better than 352x240 after encoding.

[devinemi83]

If capturing from a source like VHS or the such,it is best to use the deinterlacing I have tried not using it and I got ugly results

[Just_Cindy]

i understand that if i don't use deinterlacing i will get lousy results.

my question is why capture two fields if one is going to be removed through deinterlacing?

[patrickm]

1- capturing at 352x240 doesn't necessarily throw away a field
2- deinterlacing doesn't necessarily throw away a field

some cards are reputed to only capture 1 field at low res, but that is not the case for all cards. from previous discussions in this forum where people have researched the tech docs for the chips, i can say that the BT878 and rage theater are among those that don't toss out a field at low res.

if you deinterlace to "keep odd field" or "keep even field" you do lose a field, but if you use a blend method or adaptive deinterlace you won't, as it uses info from both fields to determine the colors of the final pixels. the quality of capturing 352x240 is not lousy, but it is a little better when properly reduced from 352x480. when you filter or do noise reduction at 352x480 before resizing, you get a better "signal-to-noise" ratio in your final picture. if you're not doing any kind of image processing before encoding, then the additonal time may not be worth the improvement in quality. (i.e. you should get a better picture, but it may be only slightly better compared to how much it increases encode time)

[Just_Cindy]

Patricm,

I have an ATI AIW Pro. Is it better to capture at a higher mpeg bitrate and resolution and then convert to a standard vcd bitrate, or is it better to capture at a high bitrate in avi format with high resolution and then convert to a standard vcd bitrate.

[Just_Cindy]

i'm sorry if this seems like a silly question but the ati seems to capture a smoother motion when capturing in mpeg format.

[WMike]

Cindy,

The assumption of your question is that you will create a VCD. For those of us using SVCD and want clearer resolution, capturing 480 is necessary and we don't deinterlace.

Mike

[patrickm]

MMC 7.1 is optimized for MPEG. AVIs should still be fine assuming you're not dropping frames though. for VCD, go with high-bitrate ( >5Mbps) I-frame only and then re-encode.

for SVCD, which is the best part of the AIW 128, set up a profile w/ 480x480 MPEG-2, IBP 15/3, 2.30 Mbps, Motion estimation 80-100%, 32x32, deinterlace, no visual masking. capture, demux, remux, burn. the quality is excellent. however, VCD is just too much compression in realtime. also, it doesn't hurt to run the SVCD captures through 'fix12c.exe' - (search the forums about it, it fixes display problems on some dvd players, most commonly pioneer)