Why Deinterlace from Tmpgenc looks better on TV?

[citizen]

I've captured a short DV clip to an AVI file. The AVI file looks perfect when played back on the PC. I've been using TmpGenc to encode the clip to CVD/PAL format (for future compatibility to DVD).

The AVI file is bottom field first(field B) as you would expect and Tmpgenc tells me it is interlaced(again as you would expect).

I find that the clip looks much better on DVD/TV playback if I use the Deinterlace(Double) in the Advanced tab. This is true whether I set the Encode mode on the Video tab to Interlace or Non-Interlaced. Strangely, if I set Encode to Non-interlaced and use deinterlace(double) and then load the resulting MPEG file then TmpGenc tells me it is an Interlaced file.

Now everything I've read on these boards and elswhere suggest that i do not need to/should not de-interlace my AVI files. But interlaced MPGE files in my instance flicker on TV.

Although my final de-interlaced CVD look OK on TV they do not look as good as the AVI file. I stil get what i think is a Ghosting effect that is not there on the AVI file. Before anyone asks I've tried CQ, 2pass VBR, CBR. I've tried Noise reduction, Ghosting etc. and the only by deinterlacing do I get a marked improvement in the final CVD.

Can anyone explain why I'm getting better results by deinterlacing the AVI and also why does the NOn-interlaced/deinterlaced MPEG file appear as interlaced when i load it back in?

Thanks

[txpharoah]

I'd love to explain, but don't have time. I don't think you're doign something correctly.

Capture cards don't normally capture properly. They grab starting with TOP FIELD A instead of broadcast standard BOTTOM FIELD B. Reverse it in TMPGenc to match your source.

Read up at www.100fps.com for info on interlace and interlace theory.

The VHS->DVD guide in my sig has some information too, though more limited to TMPGenc and ATI captures.

[cruiser80]

I too am getting a shimmering effect when trying to copy VHS tapes to DVD and playing on my tv.
I capture the PAL tape with virtualdub at 720*576 and create an mpeg2 file with tmpeg.

I have read for days various posts re. interlacing and I have tried all settings with field order and can only get rid of the shimmering if I deinterlace (which goes against what is said elsewhere), field A fisrt gives slightly better results, but the shimmering is still there and a combing (I think thats the right term) effect can still be seen.

Maybe I am missing something very simple but its driving me crazy reading the success others have but which I cannot replicate.

Please help with any suggestions.

[txpharoah]

Your capture card may not AT ALL properly grab interlace. Unfortunate, and not definite, but its a thought.

[cruiser80]

I am using a matrox G400-TV card. Don't know whether it has problems with interlace or not.

[txpharoah]

I am using a matrox G400-TV card. Don't know whether it has problems with interlace or not.

Check out the MATROX forums.

[fmctm1sw]

Wow.. That 100fps.com got really deep. Someone help me out. Speaking of totally analog caps from my cable box/vcr/camcorder, should I be capturing at 60fps? I see there is much talk about 50fps (PAL) and deinterlacing and good products. I still only need to worry about deinterlace if I'm going to view it on a progressive display right?

[txpharoah]

Wow.. That 100fps.com got really deep. Someone help me out. Speaking of totally analog caps from my cable box/vcr/camcorder, should I be capturing at 60fps? I see there is much talk about 50fps (PAL) and deinterlacing and good products. I still only need to worry about deinterlace if I'm going to view it on a progressive display right?

Capture interlaced if the sourced is interlaced and the end result will be watched on an interlaced display (tv). If you want to watch your captures only on the computer (progressive) then deinterlace.

Deinterlacing an interlaced item WILL RESULT IN LOSS. Now, as 100fps.com shows, some are not as bad as others, but once interlaced, there is no going back.

Never capture more than 29.97 fps in NTSC or 25fps in PAL. Not for home work. Some of that higher-rate stuff was for other pro uses, nothing you'd ever need (or honestly want) to work with.

[DJRumpy]

Make sure you VHS caps are not telecined as well. You can inverse telecine these back to a progressive source. The output will look much better than a deinterlace effort on a telecined source.

Nice link by the way txpharoah

[SatStorm]

There are ways to deinterlace with no quality loss.
For NTSC, Inverse telecine is the best way. For PAL, the best way I know has to do with fields delay/offset. It is like readjusting every second field to mach the first one. It is not true de-interlacing and don't disappear 100% interlace lines, but it is the best method for not loosing detail!
There some virtualdub filters for that, do a google search I don't remember from where I found them!

[DJRumpy]

Interlaced material, and telecined material are not the same thing. If you attempt to deinterlace a true interlaced source there will be unavoidable artifacts in your output. Attempting Inverse Telecine on a true interlaced source, and you'll end up with a mess.

Even the inverse telecine process, when run on a proper telecined source will sometimes miss a frame or two due to changes in the telecine pattern that the filter doesn't detect properly. The output tends to be generally close to the original if the filter settings are correct.

You can find the settings to IVTC in VirtualDub under the Video | Frame Rate. Select the 'Reconstruct From Fields - Adaptive under the Inverse Telecine section. This will remove the telecined frames or Inverse Telecine (IVTC) your output. Leave the other options on that menu page off (No Change, and Process All Frames ).