Since it is analog, it is top field first.

Is that true? I think the field order is determined by the capture device and, if it is captured to the NTSC DV format, it will be bottom field first.

Lots of variables here. Make sure the project settings are standard (in terms of field order). Same thing for the media and the render settings. You might try rendering 10-20 seconds to DV tape and play that back from your camcorder to a TV monitor. Also, I would make sure you can render the telecined version and have it look correct before you use the IVTC script.

...the field order is determined by the capture device and, if it is captured to the NTSC DV format, it will be bottom field first.

That's strange, maybe I should have done more research before I posted. I was explained to a while back that analog is upper-field first, DV is lower-field, and HDV is upper-field.

I guess things just aren't as simple as I thought. Thanks John.

j razz

Did some exhaustive testing using a short clip and ALL variations of:

Project template: NTSC DV or NTSC DV 24p
Deinterlace method: none, blend, interpolate.
Field Order lower, upper, progressive (24p project)

For all renders using the DVDA NTSC standard video stream template, I get the blinds.
For all renders using the DVDA 24p NTSC video stream template, no blinds.

The blinds, when they occur, do so on 2 of 5 frames, ie you get the 3-2-3-2 cadence. 3 frames no blinds, 2 frames blinds. My weak understanding of pulldown and deinterlacing is showing here.

All of the above renders came out 21 frames long, the length of my original.

Then went to frameserving to AVIsynth to MC standalone encoder using this script from JohnMeyer:

loadPlugin("C:\Program Files\AviSynth 2.5\plugins\Decomb521.dll")
AVISource("V:\temp\frame.avi")
Telecide(show=false,order=0,guide=1,post=2,vthresh=60)
Decimate(cycle=5)
AssumeFPS(23.976, true)
ConvertToRGB32(interlaced=false)
Levels(16, 1, 235, 0, 255, coring=false)

Project set as DV NTSC when rendered gets the window blinds effect and is 15 frames long. 15/21~ 70%, shouldn't it be 80%? ie 24/30? About 17 frames unless there's a nonlinear reason for a frame to get dropped at each end.

For grins I set the project properties to 24p NTSC and frameserved to the same script above. This seems like you're doing IVTC twice now, once by vegas and once by AVI synth. I expected some kind of error instead it ran, and it looks good with no "blinds". This was 12 frames long which is 80% i.e. 24/30.

My weak understanding of pulldown and deinterlacing is still showing here.

thanks again all,
rocky

If you are getting duplicate frames or other weird stuff, you need to change show to "true" and then experiment with vthresh. The Telecide doc describes this. This will make sure you don't get lots of duplicates or combs in the output.

Jrazz,

Generally, what you will find is that DV AVI footage is always lower field first, regardless of source. So if you capture VHS footage from a DV AVI converter it will be lower field.

But if you capture using a device that captures as MJPEG, it will be upper field first. It has not been converted to a DV AVI file. Since it used to be common for A/D capture devices to use MJPEG it was accepted that analog digital captures are upper field first.

Dave T2

I'm capturing as DV AVI.

Ignoring the Telecide results for a minute, If I'm rendering with Vegas' MC encoder, do I always need to render it as 24p if I have telecined source? That is the only way it seems to be working right.

OK, I've experimented with the threshold level to no effect. Have a look at this still and see if you can give me a clue what's going on.



http://www.cindyandrocky.com/

thanks all,
rocky

bump

If I'm rendering with Vegas' MC encoder, do I always need to render it as 24p if I have telecined source?

No. If you capture as 29.97 NTSC DV, you render it as 29.97 NTSC DV. 24p is only if your video (not the original film) is 24p. This will only be true AFTER you use the IVTC process which recovers the original, pristine, progressive film frames.

The simple way to do this project is to just render the video using the standard DVD Architect NTSC template in Vegas, and then render the audio using the Stereo AC-3 template. Combine the two in DVD Architect. Create the DVD. View on a standard TV monitor.

I just looked at the screen capture you posted. That big ugly blotch in the middle of the picture is definitely NOT simply combing artifacts. Instead, what I see is something that looks like a shutter blade.

Are you sure that this videotape was telecined??? Telecine refers to a very specific process that is only done with a very high-end piece of equipment, like a $50,000 Rank Cintel (although my $2,000 Workprinter can do it). Each frame is captured individually, and then AFTER that capture, they are combined in a "3:2 pulldown" sequence where fields (two interlaced fields per frame) from each video frame are duplicated in order to increase the number of frames per second from 24 to 29.97.

However, many low-end film transfer systems simply point the video camera at the film projector and grab the results. If you look at the results, one frame at a time, you will see some frames of video that represent blends of adjacent film frames. If done correctly, the shutter on the video camera should be set to exactly 1/60 of a second during this capture so that the shutter is open the entire length of time during which each field is "exposed" (in NTSC video, each field represents roughly 1/60 of a second in time). However, it the video camera's shutter speed is set to something higher than 1/60 of a second, you may actually see a dark shadow of a shutter. This will ruin the transfer.

In order to really tell what is going on, can you do the following:

1. Put the original, unaltered video (the file that resulted from your capture of the VHS tape) on the Vegas timeline.
2. Select exactly one second of that video.
3. Render that one second loop, using the standard DV, AVI template.

This should simply cut one second of the video without altering it.

Upload this to some site. You can use http://beta.yousendit.com or any other similar site. I'll take a look at it and see what is going on.

I'll do that John. I've some new data now: On the Vegas timeline I stepped through the original capture a frame at a time looking at it and saw a clear 3-2 pattern, i.e. 3 frames looking fine followed by 2 combed frames.

Project properties are standard NTSC 29.97 interlaced.

After rendering, this effect occurs on the 2 frames of 5 that are combed.

thanks,
rocky

Here's a link to the clip:

http://www.savefile.com/files/8563602

weirder and weirder, getting inconsistent behavior. That is, right now I'm not able to reproduce this effect. I need to do some more experimenting, but right now it looks like it might be affected by Vegas' preview DRAM setting. I have network render problems if I don't set it to zero (also wax requires it set to zero) but I like to have it set to 1024 MB for editing.

rocky

The file you posted looks absolutely fine. It is exactly just like you said, namely a telecined movie. I used the IVTC script and created a very nice 23.976 fps progressive clip. You can download that one-second clip here:

23.976 IVTC of your clip

Note that when you bring this into Vegas, you need to set the Vegas project properties to 24 fps film, not 23.976 IVTC. I am not sure what Vegas does at 23.976, but it sure doesn't seem right. If the sound gets out of sync, then change this back to 23.976. Also, right click on the media itself, select "Properties" and then select the Media tab. Change the Field Order from Lower Field First to Progressive. This tells Vegas that there is zero temporal information between fields in each frame. If you playback the clip with each of the four variations of Project properties set to 24 or 23.976, and the media field order set to Lower Field vs. Progressive, and then view the results on the TV monitor (NOT your computer display, which is misleading), you will get the best results, I think, if you follow my suggestion.

So the good news (or maybe it is the bad news) is that everything seems to look just fine with your clip, and the IVTC script works perfectly, creating a gorgeous looking 24 fps progressive clip that will give you a DVD that will look ten times better than what you would get if you encoded the clip without doing the IVTC.

Thanks John for all of your help. I have not been able to reproduce the "window blinds" effect so am unable to say what was causing it. It was reproducible every render for a while. I know because I did a controlled experiment rendering the same clip about 10 times with different settings trying to get it go away - then it went away and I can't get it back.

In any case, now that it's gone, I have successfully done an IVTC of the project using your script - it does look much better, especially when I project it on a screen.