To Deinterlace Or Not?

[ulTRAX]

I've used plenty of video software in the past few years but the options in TMPGen Express have me scratching my head.

I'm trying to convert some NSTC video to DIVX. But so far the results are not that good... even at 2-pass high bitrates. There the blockiness and the video doesn't look that clear.

Which brings up my question... if the source is 29.x fps NTSC 480i... should I try to convert it to 30fps 480p? If I do what deinterlace should I use to maintain sharpness? The manual really isn't that clear on which is best... only some setting may reduce sharpness.

[ulTRAX]

how can one tell interlaced vs progressive?

I've tried to convert some DVD VOBs to DIVX using TMPGEnc. But regardless if I export to 29fps interlaced or 30fps progressive neither looks as good as the original... there's just too much stepping on vertical lines. GSpot can't tell me if the originals are interlaced or progressive. VirtualDub, another suggestion won't open VOBs even if they are renamed mpgs.

But what's more confusing is this possibility... from a discussion at

http://www.videohelp.com/forum/archive/how-can-i-tell-if-a-video-is-interlaced-t333526.html

"No software will be able to tell for certain whether a video contains interlaced frames or not. You have to use your own eyes and a viewer that doesn't deinterlace.

Note you are dealing with two issues here: whether the frames contain interlaced fields (the two fields come from two different pictures or two different points in time) and whether the video was encoded as interlaced (how the encoder treated the fields internally). Anyone can take a progressive source and encode it with interlaced settings. Conversely, anyone can take an interlaced source and encode it as if it were progressive. Software usually only tells you how the video was encoded, not what the frames originally contained. If you have interlaced video that was compressed as if it was progressive you still need to handle it as interlaced. The other way around, progressive video encoded as if it was interlaced, is more forgiving."

Yikes! Can this be true? So how can one really tell what one’s source file is in order to choose the proper export mode?

[MilesAhead]

I would try AutoGK with default settings if you haven't already. If you are getting blocky output I haven't run into this using AutoGK where the input looked good to start. It's free so no biggy if you discard it.

[paglamon]

VirtualDub, another suggestion won't open VOBs even if they are renamed mpgs.

It will, with the mpeg2 plugin.

Fantastic insight into "interlacing" here:http://neuron2.net/LVG/interlacing.html

[ulTRAX]

I would try AutoGK with default settings if you haven't already. If you are getting blocky output I haven't run into this using AutoGK where the input looked good to start. It's free so no biggy if you discard it.

I tried GK a month ago or so. Why did I stop using it? Oh, because I wasn't sure it could meld two VOBs together.

The issue isn't blockiness. I'm converting at a pretty high bit rate of about 1800kbs… about 330megs for a 25 minute show with a 720x480 resolution. The issue seems to be that no matter what settings I use, the DIVX video seems to have much more jagged diagonals than the original VOBs which I'm assuming means half of the original data, one of the fields, has been discarded. I’ve tried every permutation included NEVER deinterlace… and they all look the same.

[ulTRAX]

It will, with the mpeg2 plugin.

Fantastic insight into "interlacing" here:http://neuron2.net/LVG/interlacing.html

Thanks... I'll check it out. Here's another one:

http://www.100fps.com/

[MilesAhead]

If the .avi outputs are the same framerate res etc. you can easily append them with AviDemux. If you don't find another solution you may want to try an AviSynth filter

http://avisynth.org/warpenterprises/

http://www.neuron2.net/

I had some video that got wicked jaggies every time a character moved horizontally in the shot. I put it through an AviSynth filter(forget which one but probably deblocking or decomb or something similar) and it was at least watchable. If your source is much better than mine(and it sounds like it is) then the results will probably be much better also.

edit: also there's a free version of Vob2Mpg available for download on
www.svcd2dvd.com. It's just a convenience utility that takes in a vob title set and spits out a single .mpg file. Then you can feed the .mpg to programs that only like to work on a single input file.