VirtualDubMod mpeg2 framerate

[_migz_]

I'm sorry if this was posted already and if this is in a wrong thread but this seems like the best place to put this question... i have one question... does VirtualDubMod use pulldown on a ripped mpeg2? i was surprised to see that the framerate of the mpeg2 video that i ripped was 23.976... i perfectly remember a time when VirtualDubMod detected mpeg2 DVD rips as 29.97.. is this a problem with the VirtualDubMod i use???? bottomline is, does VirtualDubMod use pulldown??? please help!

[Pinstripes23]

AFAIK vdubmod won't read the pulldown framerate, and I've never seen it read it as long as I have used it.

[_migz_]

ohhh i see.. thanks thanks! maybe my eyes just read it wrong.. what a relief. and i thought there was something wrong w/ my virtualdubmod. thanks.

[jagabo]

VirtualDubMod doesn't perform the pulldown. VirtualDubMPEG2 does perform the pulldown unless you disable the feature.

[_migz_]

ohhhh!!! there!!! thanks so much for the info! finally i can convert it in 29.97 fps... but.. is it possible to enable this option in VirtualDubMod??

[jagabo]

I don't think there is any way to make VirtualDubMod perform the pulldown. Why do want to?

[_migz_]

oh ok i just though that VDM could do pulldowns. never knew that there was VirtualDubMPEG2... 'till now. haha! thanks!

[manono]

finally i can convert it in 29.97 fps

Why do want to?

Unless you have some reason for doing that (some silly player requires it, or something like that), it's not such a good idea. The "true" framerate is 23.976fps, and by converting to 29.97fps you'll be wasting bits, and making the resulting video play choppy, or blurry, or interlaced, or some combination of the 3.

[_migz_]

soooo. its really better to inverse telecine the video rather than deinterlacing it??

[guns1inger]

If the source is encoded at 23.976 then you don't need to inverse telecine it, just use it as is, without applying pulldown.

[_migz_]

yup i understand that ... but if the mpeg2 video is at 23.976 and pulldown is automatically used (like ripped DVD's right?), is it better to use inverse telecine feature, or disable the option 'Honor "repeat first field" flags' in VDUBMPEG2?

[jagabo]

If the source is 23.976 fps and it's been converted via pulldown to 29.97 fps, then yes it's best to inverse telecine back to 23.976 fps (depending on what you plan to do with the video). But since you have a choice, just leave it at 23.976 fps to start with.

Pulldown followed by inverse telecine will slow things down. IVTC is difficult to do perfectly. VirtualDub's automatic IVTC isn't very good. Most players do not handle interlaced AVI files very well. 29.97 fps video will require more bitrate to encode that 23.976 fps video.

The only time it's necessary to add pulldown in VirtualDub is when the MPEG file uses variable frame rates and pulldown is needed to create a stable 29.97 fps. Or if you are creating DV AVI files or some other format that requires 29.97 fps.

[manono]

is it better to use inverse telecine feature, or disable the option 'Honor "repeat first field" flags' in VDUBMPEG2?

Neither. It's not only better, but best, for you to create a D2V project file in DGIndex using the Force Film option, and then frameserve a 23.976fps AviSynth script file into whatever you want (VDub, VDubMod, VDubMPEG2, etc.).

If the video is hard telecined and requires that you use the Honor Pulldown Flags option in DGIndex, then you apply an IVTC filter in your script and frameserve it as 23.976fps into your encoder.

The last thing you'd ever want to do to a film sourced video is deinterlace it.

[_migz_]

ohhh ok... hmm.. maybe i'll try playin w/ DGIndex.. i haven't really tried usin it. thanks for all those info guys! appreciate the help!

[manono]

Make sure you read the 3 docs that come included in DGMPGDec, especially the QuickStart Guide:

http://neuron2.net/dgmpgdec/QuickStart.html

[_migz_]

oh there! i was lukin for a guide in google. thanks for posting!

[Alex_ander]

... does VirtualDubMod use pulldown on a ripped mpeg2? i was surprised to see that the framerate of the mpeg2 video that i ripped was 23.976... i perfectly remember a time when VirtualDubMod detected mpeg2 DVD rips as 29.97.. is this a problem with the VirtualDubMod i use?

It simply ignores pulldown flags (if any) and decompresses the actual number of frames, so you see the actual encoding framerate 23.976 for a film-sourced video encoded at 23.976 with pulldown flags and in your other case you see 29.97 for a video telecined at avi level (or originally interlaced), then encoded at 29.97 as any interlaced video.
Be careful when selecting field operation in DGindex: the only case when you can identify the source as encoded at 23.976 is when you see the word 'Film' in preview. Then you can IVTC at project level by using 'Forced film' mode. In all other NTSC cases you deal with video encoded at 29.97 and you have to make project with 'Honor pulldown flags' (as mentioned), then perform IVTC in Avisynth (if film-sourced).

[_migz_]

hmmm through your experience, is the IVTC feature of virtualdub better than using DGIndex to Inverse Telecine? because jagabo said VirtualDub's IVTC isn't that perfect.

[manono]

hmmm through your experience, is the IVTC feature of virtualdub better than using DGIndex to Inverse Telecine? because jagabo said VirtualDub's IVTC isn't that perfect.

The IVTC feature of VDub isn't better than anything. But you're asking about apples and oranges here. When you Force Film in DGIndex, you're pretty much just reading the flags and removing duplicate fields based on the RFF flags. It only really works when it's 100% Film, and it's not a true IVTC. If there's some video or hard telecine in there, it just removes every 5th frame, and during those sections you'll get jerky playback, interlacing, or both. If it's not 100% Film (most guides say over 95% Film) but is sourced from film (a mix of hard and soft telecine, or pure hard telecine), you should do a full IVTC. In AviSynth and not VDub. Time for you to learn some AviSynth. Or, if making AVIs, let AutoGK do it for you.

[_migz_]

ohhh soo there are different types of telecine... haha actually i know how to use AviSynth.. but the only thing i use it on is to open a video using Directshow. ).. that's it..

"DirectShowSource("blahblah", blah, blah)" that's the only thing i use it on. hahaha. and sometimes i set the framerate.

hmm.. maybe i'll try AutoGK too.

[manono]

In the AviSynth world, soft telecine refers to progressive 23.976fps with the flags set to output 29.97fps. When you open that in VDubMod, all you see is the progressive 23.976fps because, as Alex_ander said, the flagging is ignored. Hard telecine refers to video already telecined and encoded as interlaced 29.97fps. When you open that in VDubMod, you see 29.97fps with 2 of every 5 frames being interlaced. A D2V project file for that kind is made using Honor Pulldown Flags, and an IVTC is applied (Decomb, TIVTC, Smart Decimate, etc.) in the AviSynth script.

[_migz_]

ohh. so there are really complicated ways of telecining... and other complicated ways of doing IVTC??... can i ask.. i have a video, when i open it in GSpot, it says that the:

Pics/s - 29.970
Frames/s - 29.970
and the Fields/s - 59.94

.. it is also an interlaced video that's Top Field First.. i never found ways to IVTC this video perfectly. i would always get jerky output and the motion was never fluent when i use virtualdub's IVTC feature.... soo does this mean that there's some hard telecining used??

[manono]

soo does this mean that there's some hard telecining used??

No way to tell from the information you've provided. If you'd like to provide a small sample, we'd be happy to have a look. Maybe it's pure interlace (30fps) and you can't IVTC it at all. Maybe VDub's IVTC screwed up. Maybe it's fieldblended garbage and you'll have to use other methods to unblend it. Lots of possibilities.

[_migz_]

soo does this mean that there's some hard telecining used??

No way to tell from the information you've provided. If you'd like to provide a small sample, we'd be happy to have a look. Maybe it's pure interlace (30fps) and you can't IVTC it at all. Maybe VDub's IVTC screwed up. Maybe it's fieldblended garbage and you'll have to use other methods to unblend it. Lots of possibilities.

If its ok w/ you, sure! i'd be happy to give u the video... its just short anyway. hmmm i'll upload it somewhere, then maybe i'll post the link here.

[manono]

We'll just need a small 10 second or so section with movement. We don't need audio. Open it in DGIndex, use the [ and ] buttons to isolate a small part, and Save Project And Demux Video. Upload the resulting M2V if it's small enough.

[_migz_]

It's actually a game rip from FFX-2 using "CubeMediaPlayer". haha ... but anyway if u wanna check it out here's the link:

"http://rapidshare.com/files/36252527/Yuna.mpg"

i'd be happy to know what information you get from it. for a long time, i was trying to reduce the frame rate to 23.976 through IVTC but.. i cant seem to do that.. i was wondering if IVTC was possible with this video.

[_migz_]

its just about 20 seconds. 12MB

[45tripp]

it's 29.97 progressive.
you leave it as is.

anything you do in attempts to reduce to 23.97 will butcher your material.

[_migz_]

ohh.. i knew it.. it didn't look like it was interlaced.. but how come Gspot detected it as an interlaced video.. is it just a glitch in Gspot or sumthin?

[manono]

Yep, can't be IVTC'd.

Bitrate Viewer, ReStream, and DGIndex all say it was encoded as progressive. Or has this been reencoded and you changed it from interlaced to progressive? Anyway, it's not unusual for progressive material to be encoded as interlaced.