IVTC a vob/m2v file before FCP editing

[kmxe]

I'm looking for ideal settings in Compressor which would let me IVTC a vob/m2v file without going through any converting generation loss (which I believe is the best thing to do).

Right now my workflow is:

1) Mac The Ripper to extract vob from DVD
2) MPEG StreamClip to get a mov version of vob, and also demux to get a m2v & aiff files

the mov file is used for editing in FCP, then i intend to use the 'Reconnect Media' option in FCP to render to a file from FCP by connecting back to m2v file

My dilemma is, I believe i should be IVTC ing the original file first before i use the 'Reconnect Media' (and i guess also de-interlace). I've been told that Compressor can Reverse Telecine, but i can't figure out what settings to use. I only got Final Cut Studio last week so still getting my head around it all. But from what I can see, I need to drag the m2v file into Compressor, then choose the settings to perform this. It seems as though that in order to do this I will have to convert the file???

Is there a way that I can IVTC & deinterlace the file before I edit in FCP with FCP & Compressor - without going a conversion to avoid a generation loss?

what would the steps and settings be?

Or am i going about it all wrong?

[Case]

What makes you think that you need to perform IVTC? If you're not sure, perhaps you don't need to do it.
Most NTSC DVDs from film source are 24 fps with just a pulldown flag. No telecine was ever applied.

[kmxe]

im still new to all this so still learning as i go!

but from what ive read, one indication of this is when you go through the video frame by frame and you see 4 frames then a duplicate frame. Wouldn't performing IVTC on this remove the duplicate frame?

What is a pulldown flag?

[Case]

What is a pulldown flag?

The pulldown refers to a "3:2 pulldown" instruction in the MPEG-2 video of the VOB. It is like telecine, but the original frames are not touched. It is done in the output signal of a set top player, not in the digital frames in the VOB.

[jagabo]

What is a pulldown flag?

See the second part of this post:
https://forum.videohelp.com/threads/316415-Check-Over-My-Options-From-DVD-to-XviD-Conve...=1#post1958565

Starting with "First you have to fully understand what interlaced video is."

[kmxe]

What is a pulldown flag?

See the second part of this post:
https://forum.videohelp.com/threads/316415-Check-Over-My-Options-From-DVD-to-XviD-Conve...=1#post1958565

Starting with "First you have to fully understand what interlaced video is."

thanks for this - ive read this a few times to try and make sure i get it all.

Just so I understand correctly - if I rip a NTSC DVD (and which it was originally filmed at 23.97fps but the resulting vob file shows 29.97fps), and I look at the video frame by frame and i see 4 progressive frames and then a duplicate - does this mean that the video has been 'hard telecined' - or not necessarily?

[jagabo]

if I rip a NTSC DVD (and which it was originally filmed at 23.97fps but the resulting vob file shows 29.97fps), and I look at the video frame by frame and i see 4 progressive frames and then a duplicate - does this mean that the video has been 'hard telecined' - or not necessarily?

In the broadest sense it hard telecined but not with the usual 3:2 pulldown. What you're describing is simply duplicating every 4th frame to convert from 23.976 fps to 29.97 fps. When watched on TV you should see 4 little jerks every second (very obvious on panning shots, for example). I've never seen a commercial DVD done like that.

[kmxe]

What you're describing is simply duplicating every 4th frame to convert from 23.976 fps to 29.97 fps. When watched on TV you should see 4 little jerks every second (very obvious on panning shots, for example). I've never seen a commercial DVD done like that.

Just to double check we're talking about the same thing, ive been looking at some of my videos closely and duplicate is not the right word to describe what Im seeing. Im pretty sure its how you describe in your other post as "Every 4 film frames has become 5 interlaced video frames. 3 of those frames look progressive because both fields come from the same film frame. But two of them look interlaced because the two fields come from different film frames." Every 5th frame in my video looks like its made up of the fields before and after the occurence.

With this video and as per my original post, I IVTC the m2v file via compressor (as im thinking that this video needs it to bring the video back to 23.976fps) and then use this IVTC'd m2v to Compressor (after doing my edit in FCP) to render to an mp4.

When I do this, for the most part the end video looks beautiful - comparable to the original vob. Except the problem im having is that every now and then there are frames which are clearly interlaced. There seems to be no pattern to this, it doesnt occur at the same intervals, nor does each occurence last as long as the next. At one point 2 consecutive frames look interlaced and at another point its 8 consecutive frames.

When I try to deinterlace during my render to MP4 instead, it gets rid of all the interlacing, except the now the video looks horrible - pixelated and 'digital'.

What am I doing wrong?

[jagabo]

Every 5th frame in my video looks like its made up of the fields before and after the occurence.

That is a poor telecine from a progressive 25 fps source. Probably a film source converted to progressive PAL then converted to NTSC. You can't use the usual IVTC methods that expect 3:2 pulldown. You can IVTC in AviSynth (Windows) with:

TFM()
TDecimate(mode=2, rate=25)

I don't know if there are any tools on the Mac to deal with this. If you provide a small sample I'll verify that the above works.

[kmxe]

ok cool - this file is roughly 12sec longs.

I used MPEGStreamClip to Demux 12seconds from the vob (NTSC Source) to a m2v file.

[jagabo]

That clip is a mix of normal 3:2 pulldown (with pattern breaks at most cuts because the video was edited after being telecined) and progressive (encoded interlaced) sections. You won't be able to IVTC or deinterlace and keep smooth motion in all shots. If you IVTC (and many IVTC algorithms will have problems with all the pattern breaks) the progressive sections will get jerky because one frame out of every 5 will be dropped. If you (smart) deinterlace the progressive sections will remains smooth but the 3:2 pulldown sections will jerky because one frame out of every four will be duplicated. Of the two, IVTC will probably work better because more of the video is telecined film as opposed to progressive. Here's an IVTC via TFM().TDecimate() in AviSynth (Windows) encoded with 3:2 pulldown flags (ready for DVD):

[Herve]

this file is roughly 12sec longs.

hello, I just saw your extract

NTSC exists in 2 flavours: 30 fps (NTSC VIDEO) and 24 fps (NTSC FILM)
your extract is build with both

the process:
the NTSC FILM part (the woman) is first converted to NTSC VIDEO (with hard -and not sft/flag- duplication of frames to fields)
and then, incorporated in native NTSC VIDEO parts (the man).
The result produced a valid NTSC VIDEO file (compliant with broadcasting)

some remarks:
- if you delete interlacing (=deinterlace), you damage the native NTSC FILM parts
- if you remove pulldown, you damage the native NTSC VIDEO part

just a tip: keep the file as an interlaced NTSC VIDEO. FCP will handle it correctly, and after editing, make a new DVD-VIDEO (it will be correctly displayed on TV)

bye

Edit:
in practice, some example (.m2v, 10MB each one, I delete the black borders =rescale, to better show the differences between each result):
- deinterlaced stream.m2v
- deinterlace strem + reverse hardcoded telecine.m2v
- normal.m2v
(was only my advise/personal choice )

[kmxe]

That clip is a mix of normal 3:2 pulldown (with pattern breaks at most cuts because the video was edited after being telecined) and progressive (encoded interlaced) sections. You won't be able to IVTC or deinterlace and keep smooth motion in all shots. If you IVTC (and many IVTC algorithms will have problems with all the pattern breaks) the progressive sections will get jerky because one frame out of every 5 will be dropped. If you (smart) deinterlace the progressive sections will remains smooth but the 3:2 pulldown sections will jerky because one frame out of every four will be duplicated. Of the two, IVTC will probably work better because more of the video is telecined film as opposed to progressive. Here's an IVTC via TFM().TDecimate() in AviSynth (Windows) encoded with 3:2 pulldown flags (ready for DVD):

i just checked your video sample - wow, thats pretty cool. i can see that the IVTC file i did had slightly better quality (except for the frames which came out interlaced which is not good) but i guess that can't be helped considering.

Ok so when compared to my sample video i can see that the image is butter smooth and not digital like my original video was. This is partly what I want. I also noticed that the fps was 29.97 and that (for example) frames 1-2, 4-5 where essentially duplicates. What I would like to do is delete the duplicates and have the video at 23.976fps instead.

would this possible?

You mentioned that

Of the two, IVTC will probably work better because more of the video is telecined film as opposed to progressive.

.

With the Compressor program I use, there is an option to 'Reverse Telecine' - I thought this was another way of saying IVTC? If so - since I've tried to IVTC the m2v with compressor, would it be fair to say that either a) im not using the right settings (actually, there's no settings to speak of) or b) Compressor is not doing a good job or c) Avisynth is doing something else that Compressor isn't doing?

[kmxe]

this file is roughly 12sec longs.

hello, I just saw your extract

NTSC exists in 2 flavours: 30 fps (NTSC VIDEO) and 24 fps (NTSC FILM)
your extract is build with both

the process:
the NTSC FILM part (the woman) is first converted to NTSC VIDEO (with hard -and not sft/flag- duplication of frames to fields)
and then, incorporated in native NTSC VIDEO parts (the man).
The result produced a valid NTSC VIDEO file (compliant with broadcasting)

some remarks:
- if you delete interlacing (=deinterlace), you damage the native NTSC FILM parts
- if you remove pulldown, you damage the native NTSC VIDEO part

just a tip: keep the file as an interlaced NTSC VIDEO. FCP will handle it correctly, and after editing, make a new DVD-VIDEO (it will be correctly displayed on TV)

bye

Edit:
in practice, some example (.m2v, 10MB each one, I delete the black borders =rescale, to better show the differences between each result):
- deinterlaced stream.m2v
- deinterlace strem + reverse hardcoded telecine.m2v
- normal.m2v
(was only my advise/personal choice )

thanks Herve but I dont think the files were uploaded?

my target file is an mp4 - would you still suggest leaving the file as is?

[jagabo]

i just checked your video sample - wow, thats pretty cool. i can see that the IVTC file i did had slightly better quality (except for the frames which came out interlaced which is not good) but i guess that can't be helped considering.

I just did a quick MPEG2 encoding at a moderate quality level to keep the file size down.

Ok so when compared to my sample video i can see that the image is butter smooth and not digital like my original video was. This is partly what I want. I also noticed that the fps was 29.97

No, the frames were encoded 23.976 fps progressive with 3:2 pulldown flags. I did that to make it DVD compatible.

and that (for example) frames 1-2, 4-5 where essentially duplicates. What I would like to do is delete the duplicates and have the video at 23.976fps instead. would this possible?

That is a problem created by your player. Those duplicates are not in the M2V file. And if they were, and you removed them, the file would no longer be 23.976 fps. Or the running time would be shorter.

You mentioned that

Of the two, IVTC will probably work better because more of the video is telecined film as opposed to progressive.

.

With the Compressor program I use, there is an option to 'Reverse Telecine' - I thought this was another way of saying IVTC?

Yes. And I did IVTC.

If so - since I've tried to IVTC the m2v with compressor, would it be fair to say that either a) im not using the right settings (actually, there's no settings to speak of) or b) Compressor is not doing a good job or c) Avisynth is doing something else that Compressor isn't doing?

B. Most IVTC algorithms don't do well with material with many pattern breaks and mixed telecined/progressive material.

23.976 fps progressive AVC MP4:

[kmxe]

Ok so when compared to my sample video i can see that the image is butter smooth and not digital like my original video was. This is partly what I want. I also noticed that the fps was 29.97

No, the frames were encoded 23.976 fps progressive with 3:2 pulldown flags. I did that to make it DVD compatible.

Ah yes sorry - i missed that pulldown reference in your earlier post

and that (for example) frames 1-2, 4-5 where essentially duplicates. What I would like to do is delete the duplicates and have the video at 23.976fps instead. would this possible?

That is a problem created by your player. Those duplicates are not in the M2V file. And if they were, and you removed them, the file would no longer be 23.976 fps. Or the running time would be shorter.

strange - i played these in FCP - i just thought FCP would ignore the flags in the preview window but i guess not. However, I did think about it and realised that my timeline was set to 29.97fps, and when i switched it to 23.976 and the video was progressive - so my mistake!

so just to make sure its clear in my head - if a file has pulldown flags - these pulldown flags tell the player to perform the pulldown (not sure if im saying it right) to produce 29.97fps?

If so - since I've tried to IVTC the m2v with compressor, would it be fair to say that either a) im not using the right settings (actually, there's no settings to speak of) or b) Compressor is not doing a good job or c) Avisynth is doing something else that Compressor isn't doing?

B. Most IVTC algorithms don't do well with material with many pattern breaks and mixed telecined/progressive material.

i guess i'll need to look for a different program on Mac which has a good algorithm to get results similar to what Avisynth produces. Unless I'm using Compressor wrong!

[jagabo]

so just to make sure its clear in my head - if a file has pulldown flags - these pulldown flags tell the player to perform the pulldown (not sure if im saying it right) to produce 29.97fps?

Yes. When the DVD spec was hashed out DVD players weren't expected to have any intelligence. So the spec allows for flags that instruct the player how to produce 59.95 fields per second (the only thing that ever traveled over analog NTSC video cables and over the air) from 23.976 frames per second video. This is often referred to as 29.97 frames per second because it takes two fields to create a full frame. And digital video files file normally weave two fields together to make full frames.

[kmxe]

Thanks jagabo - your help has been invaluable! I appreciate the time you've taken to explain to a newb these things!

[Herve]

thanks Herve but I dont think the files were uploaded?

hello, I just check the links, all seems OK (files are directly uploaded on VideoHelp server)

my target file is an mp4 - would you still suggest leaving the file as is?

ooops, I didn't noticed it (I only check contents of your file)
Usually mp4 has to be progressive, so you don't have other choice for your output.

my personal taste will be to deinterlace but keep 30fps (to remove duplicate frames/fields is not safe if all vidéos inside are not native 24fps)
take a look to her legs at the end of the extract, a removed pulldown is more jerky than keep 30fps and deinterlace (in fact this video is a b*****t to convert to another format)
If the director was more coherent (only one format used), it will be easier for you and you could correct it (even an hardcoded pulldown like this). But your video is "not made to obtain a good result during conversion"

So you have to do your own partial choice, and none will be perfect

bye