To Interlace, or not to Interlace, THAT is the question!!

[whoman421]

I am a big A-Team fan, and since the episodes are not going to be released on DVD [here in the USA], my only option is to capture it off of TV. I have an ATI AIW 128 PRO and a Celeron 1.8GHZ. Up until the time I saw that DOOM9 had come out with a CAPTURE GUIDE, I was using ATIs own Multimedia Center to do my capturing. Since this software can perform on-chip realtime MPEG2 compression, it is good, but since it has HORRIBLE audio quality [no way to turn off it's realtime audio compression], this was starting to seem like a waste of time.

Then I read the CAPTURE guide, and discovered the wonders of LOSSLESS codecs [since I can use CCE for my MP2 compression later]. This was great for a few weeks, until I noticed that almost all of my content had a GHOST effect [I had to look really close to see this]. After countless hours of testing, I came to a few conclusions:
1 Most captures will have 3 perfect consecutive frames, followed by 2 improperly interlaced ones [over and over]. These 2 frames cause the GHOST effect
2 If you capture with a vertical resolution of 480, the capture will be interlaced
3 If you capture with a vertical res. of 240, you will get a ghost effect, since it is just resizing improperly interlaced frames.
4 If you capture with a vertical res. of 480, and use CCE to convert it to MP2 [ensuring that PROGRESSIVE FRAMES is not checked], you get the GHOST effect [from the 2 improperly interlaced frames mentioned above].

I've read quite a bit about this problem, and no one has any suggestions that really do anything to solve this problem

My question is more of a "WHY" then a "HOW":
Why can't I capture interlaced video in its original interlaced form, and have my "PLAYER" properly interlace the file during playback? Isn't this how interlacing is supposed to work in the first place? It seems most peoples 'workarounds' are nothing more then trying to convert INTERLACED source into PROGRESSIVE video. That is fine, but why?
I know that the DIVX people need progressive frames, but since I'm making DVDs, I wouldn't mind keeping the original INTERLACED source. I know that this can make the filesize larger, but I'll deal with that when I'm burining ;)

I've been able to capture THREE'S COMPANY without this problem, but that is the only show!

Also, I see quite a bit of people talking about de-interlacing AFTER the fact [perhaps using AVISYNTH] however I have yet to find a combination of filters that can properly fix the 2 out of 5 improperly interlaced frames. Anything I try will leave a GHOST effect.

Any ideas or thoughts that would contribute to the discussion of this issue would be very much appreciated!

:)

[scharfis_brain]

You have decribed the telecine effect.
Telecine is used to convert 24fps progressive video to 60 fps interlaced video.

telecine can be undone by doing an IVTC (inverese telecine)

this can easily be done with a AVIsynth script:Loadplugin("Drive:\Path\decomb.dll")
AVIsource("Drive:\Path\***.avi")
telecide(post=false)
decimate(cycle=5)

[whoman421]

I found decomblegacy.dll [which looks like the right one from the README] but I still have a question:
Did VirtualDub capture my 480 content as progressive?
The reason I ask is because it seems like this DECOMB.dll isn't actually properly reconstructing the progressive frames, but rather it is just trying to fix the COMBING effect on those 2 bad frames. I haven't done much testing to see how the quality is, but those types of things usually aren't perfect. So if my assumption of what DECOMB.dll does is right, my next question would be:
Is there any way to do IVTC in virtualdub at the time of capture, so that it can reconstruct the progressive frames correctly before it is written to disk?
I am suspecting that there isn't [but hoping someone will reply, proving me wrong] because of the fact that the video would have to come into VDUB at 29.976 but be written as 23.976

Man!! If only I could find a way to write the DVB streams [dishnet] directly to disk instead of dealing with all this! Anyone know where I might be able to find info on that? :D PM me...I'd VERY MUCH appreciate it!

scharfis_brain: Thanks again for the insight ;)

[vhelp]

hi whoman421,

If I'm not mistaken, MMC does not support capturing w/ a de-Telecine
or 3:2 mode, but I could be wrong. Maybe the latest version does.
You'll have to verify this out to be sure, by visiting ATI's website.

There are some sofware that do allow you to capture.. I think the app
is DScaler or something like that. Juts do a search here to to find
out which app. Try search params like 3:2 and DScale or something.

Otherwise, if there are no apps that capture w/ de-telecine in mind,
or is too costly to obtain, then the only thing you can do (unfortunately)
as well all have ben doing all along, is continue capturing at 29.970
(PAL 25 fps) and then analize your video in vdub's time-line and observe
the frames patter. If its that tipicle 3:2 pattern you described above,
then you are safe to utulize any IVTC plugin or script you are aware
of, else it could either be a weired Telecine pattern or finally, its
just plain Interlace. On the other hand, some sources could very well
be progressive. I've noticed that a lot of CBT are now providing good
quality progresseve materials, though some have to be slightly cleaned
up.

And, don't forget, that you also have to consider the quality that the
source is being aired. And, that not every cable and/or Satellite
provider is airing (using) the same source materials in a given region, add to that, that some of these entities jimmy their source a
little or inlucde a logo or even fake a letter box. I found this fake
by accident one day w/ my Osprey-210 card. Anyways..

Try and do some searching on software real-time de-Telecine or similar
wording, for capture cards - probably DV cards as well.

Have a good day.
-vhelp