Once Again Very Confused About IVTC

[ThePanda]

Hi, I have an anime on DVD. In DVD2AVI when I did preview it said NTSC and INTERLACED and never changed. Does this mean it is definitely 29.97fps and doesn't need IVTC? I loaded it through VFAPI into VirtualDub, and when I scrolled through 30 frames or 60 frames during an action sequence, I'm pretty sure there was movement in every frame. This also seems to suggest that it's 29.97fps, or is it possible that some frames were just interpolations between 2 other frames or something and it does in fact need IVTC? I am pretty confused right now :D:confused:.

By the way, when I do use IVTC I do in VirtualDub "Reconstruct from fields - adaptive", and then I apply the deinterlace(blend) filter after that as well, because I hate when IVTC misses a lot of those lines during movement, and I figure the blend doesn't do too much harm for anime anyway. Is there a better way to do this?

Any info on when IVTC is necessary would be GREATLY appreciated.

[jggimi]

IVTC stands for InVerse TeleCine.

Telecine is a process by which a 24fps film's framerate is altered. Either to 25 or 29.97fps.

If the content's original source didn't have sprocket holes in the sides, it should not be inverse telecined.

Anime is created either for broadcast or for theatrical release. The latter is the one to inverse telecine. Based on dvd2avi's status window, you probably have the former.

There are several ways to inverse telecine. Force FILM in dvd2avi is a simple, quick and easy way. You can also use a variety of inverse telecine filters with Vdub or nandub, such as decomb's.

[ThePanda]

Thanks. I guess I don't need to IVTC then since it was a show created for TV.

[soujir0u]

But most anime I download are encoded in 23.397fps... They must have IVTCed it.

[ChristianHJW]

Originally posted by soujir0u
But most anime I download are encoded in 23.397fps... They must have IVTCed it. or people dont have a clue of what they're doing ...:D

[soujir0u]

Heh...BTW, I have a question...

I have a DVD that says NTSC Interlaced 29.97fps. However, all the frames are progressive, and all the frames are different (no repeating frames). The video was transferred straight to DVD, so I guess it's not telecined. Should I use Force FILM to change to 23.397fps?

[western shinma]

Even though most anime is made for TV, it is almost always originally drawn at 24 fps, so IVTC is usually appropriate. If it is a more recent show with computer graphics however, some scenes might be 30 fps.

As for your DVD soujir0u, if there aren't any repeated frames and everything is progressive, you definitely wouldn't want to use force film, or any deinterlacing either.

ThePanda: DVD2AVI's information doesn't tell you the whole story. Usually if you have a disc that is 100% NTSC, it should be encoded at 29.97 fps, but there are exceptions. The only way to be sure is to scan through a few frames like you did in VirtualDub or some other tool. Some live action TV shows need IVTC even, although this isn't as common as with animation.

[ThePanda]

Thanks for the replies.

shinma: When I am scanning though in VirtualDub, do I know that it needs to be IVTC'd if there are 5 repeated frames every second, or is that not how it works?

It stinks that they have to ruin the DVDs with all this IVTC and interlacing crap :D. I can tell which frames are interlaced even after using the deinterlace filter, because the lines are all jagged and stuff.

[Taric25]

For any DVD, I IVTC. If it's 29.97 prrogessive, 98% FILM or NTSC I IVTC instead of de-interlace of force film. I always see artifacts on my computer moniter not matter if it is on Force Film, deinterlance, or left as it is. If a source is interlaced on DVD it still looks bad on my moniter. This is why I always IVTC. When I IVTC, it's like watching the 35mm FILM at 24fps.

Besides, I get more bits/frame. :)

[ThePanda]

Wow, it seems that Media Player can't even handle my 640x480 picture w/ AC3 audio and DirectVobSub running at the same time; the video lags behind the audio on my 1.33ghz athlon. I guess I didn't notice it before because I had been IVTCing pretty much everything, so it didn't have to play as many frames per second.

[jggimi]

Originally posted by soujir0u
Heh...BTW, I have a question...

I have a DVD that says NTSC Interlaced 29.97fps. However, all the frames are progressive, and all the frames are different (no repeating frames). The video was transferred straight to DVD, so I guess it's not telecined. Should I use Force FILM to change to 23.397fps? I think you may have answered your own question. The video was transferred.

Don't confuse Telecine with Interlace. One is what's done to film to make it ready for display on TV, the other is a video characteristic. Can you have both? Sure. Many film distributor's leaders are video, spliced onto the front of telecined content. That's why dvd2avi will show a percentage if you preview from the beginning. If you set the start to the middle of the content, you probably will see FILM without a percentage ... assuming a transfer of a 24fps film.

[soujir0u]

Originally posted by jggimi
I think you may have answered your own question. The video was transferred.

Don't confuse Telecine with Interlace. One is what's done to film to make it ready for display on TV, the other is a video characteristic. Can you have both? Sure. Many film distributor's leaders are video, spliced onto the front of telecined content. That's why dvd2avi will show a percentage if you preview from the beginning. If you set the start to the middle of the content, you probably will see FILM without a percentage ... assuming a transfer of a 24fps film.

Oops, what I meant was that the video was released straight to DVD (and VCD) without ever being shown in theathers or TV... Guess I'll borrow it from my friend again and check to see if it shows FILM at the middle...

[western shinma]

Keep in mind it is entirely possible to have 100% telecined film encoded as a 29.97 fps interlaced stream, although I've only seen this on one DVD. Still, you have to look at a few frames in a row to be absolutely certain.