VHS --> NTSC film SVCD? IVTC and pulldown...

[thestallion]

I'm preparing to capture a couple of VHS movies to put on SVCD, and I'm wondering if my "plan" is correct:

capture at 480x480 29.97fps
inverse telecine to get 23.97fps
encode MPEG-2 with 3:2 pulldown in TMPGEnc

I've found all sorts of info about "force film" etc for DVD rips, but little info for actual captures from VHS... I want to be sure that I'm understanding properly that I can take my 29.97fps capture and end up encoding at 23.97fps through IVTC and 3:2 and have decent results. So please correct me if I'm wrong in my assumptions:

I should capture at 29.97fps to get all the fields
I should IVTC to get rid of repeated fields and produce 23.97fps
I use 3:2 pulldown to insert flags in the final encode to play the 23.97fps at 29.97fps.

I've done successful SVCDs at 29.97fps but would like to squeeze a little more quality out of the stuff that is probably 23.97fps. Having only a 10GB HD and a PIII/450 cuts down my time and power for experimenting, so I thought I'd get some advice...

[kinneera]

Your plan is correct. (Assuming the VHS source is in fact film).

[Tony Yip]

I was about to ask this same question.

I'm assuming you capture you VHS movie film using VirtualDub or Avi_io
then take the resulting avi files and encode using Tmpeg.

Can somebody provide a Tmpeg template to do this since I'm still not sure
what some of the settings are to do this correctly.

For instance, do we using VBR mode for the ecncoding and is there an order in which we use the filters in the advanced tab.

[thestallion]

I'm ASSUMING that the source is film, is there any way to be sure based on the capture file?

[vhelp]

thestallion, and others (newbies)

yeah, i think this is how it's done - I do it, and it works every
time for me.

Assuming you're in virtual dub (it's quicker to add just one avi
file for this test)
.
.
* magnify clip at 2x
* quickly move to scene with movements (hands, etc. )
* then, using your cursor rt/left keys, crsr right, and count
how many times your clips is clear.
* now, continue crsr righting around, till you hit your first
interlace or squigly lines and begin counting that as your first.

Ok, based on above, in short, you should see a sequence like this:
123,45 123,45 123,45
3 2 3 2 3 2
or better yet, 3:2, 3:2, 3:2. . . he, he... .. ..

Another tip, don't count it when the scene changes complletely, as
this will not always keep the 3:2 sequence proper in your head, as
as on screen.

You can't alwyas go by this method though because a lot also has
to do with your capture card too, and not every tv program is the
same. Some are "film", "progressive", "F'ed" and what not.
Also, any dropped frames will "F" up your 3:2 structure in your
avi files, and when you proceed to encode cce or tmpg, you have to
take this into account when you view your final enocde, and see
for yourself how quality in some scenes can be awful or distorted.
If you drop frames, this WILL reflect your 3:2 sequence. Sometimes
it's better to just encode with "interlace", unless you're encodes
are for VCD, then it doesn't really matter, he, he...

I have other tips about how to handle this problem, but will spare
you the confusing details (though it works for me) its for for
advanced encoders. The above is MORE than enough for the newbie
If you have any further questions on this, ask someone else here,
cause I'll only put you ta sleep with my long details. . .

Well, hope I've ben helpful.

-vhelp

[FranckV]

I tend to desagree with using the 3:2 pulldown in TMPGENc because to me this does not set any flag telling the DVD player to play the 23.97 movie at 29.97, it recreates the telecined effect you just got rid off by IVTC the file (please someone correct me if I am wrong).

Moreover, if you use the 3:2 pulldown from TMPGEnc, make sure you set the output rate to 29.97 otherwise, if set to 23.97 TPMGEnc will do the pulldown on the 23.97 !!

The real question is: can the DVD player play a 23.97 fps movie. If yes then bingo, you can capture at 29.97 - 640 x 480, change the frame rate down to 23.97 by getting rid off the extra artificial frames (do not forget to change the timing in the sound stream, IVTC suppresses 6 frames per sec of movie so you need to "delay" the sound by 33ms for every deleted frame).
Then filter & resize the movie to 480 x 480 and then encode using either TMPGEnc or CCE.

If the DVD player can't play 23.97 fps movie, then no choice, you have to keep the source at 29.97 fps and encode it that way.

Question to Video Gurus out there:
If the DVD player (like my Samsung DVD1000 combo) can play the 23.97 fps movie it means it must be adding frames because the TV only understands 29.97 so is the DVD player really recreating the 3:2 pulldown properly or is it just repeating 1 frame every 4 (jerky effect when fast background movement) ? If someone can tell me the answer to this last one, I would appreciate.



Hope this helps

[kinneera]

Sorry, but you need to review your understanding of these settings. The 3:2 pulldown on playback setting in TMPGEnc is merely a flag in the MPEG header. The 3:2 pulldown filter, however will undo the IVTC. If you are making an SVCD, you will obtain the highest quality by doing an IVTC and applying the 3:2 pulldown flag - which will then cause your DVD player to telecine on the fly. This is exactly how most DVDs are encoded, and the weak link is your NTSC TV which expects an interlaced signal, not your DVD player.

If you do use the 3:2 pulldown flag or filter, do NOT set the output framerate in TMPGEnc to 29.97 or there is no telling what will happen to the output.

[FranckV]

Ok, I'll test it witn the different options.

[malducci]

Yeah, what Kin said. Capture your video at XXX by 480, you can resize the video and still do the IVTC as long as the vertical resolution stays at 480( want to keep both fields ). Apply the IVTC to the video, assuming you know the video was film based or originally 23.976fps. Encode the video as MPEG2 at 23.976. I personally use pulldown.exe apply the 2:3 flags. This will insert flags so the DVD player will play the video back as 29.97fps ( it doesn't actually add frames ).

[FranckV]

What are the settings to be used with Pulldown.exe ?

[malducci]

example:

pulldown d:\movies\sample.mpv d:\movies\pulldown.mpv

syntax = pulldown *source* *destination*

type pulldown /? for options, but the default options should work fine. Pulldown is for video files only - not video files with audio. Just re-mux the audio to the new MPV file and waalaa.