23.976 Vs. 29.970

Stormshadow · 12th December 2006, 01:10

I just wanted to see if people could clear something up for me...

When ever i do a NTSC dvdrip then sometimes the resualt end up with a 29.970 framerate (as sourse of course) but i've had plenty of people telling be that when it uses that framerate then it's bad IVTC (everytime apperently, if i listen to them)

I just wanted to know if thats true??? (and maby a reason)

If yes is there a way to slow down the framerate to 23.976 no matter what in autogk???

I've played around with the hitten option but with no luck...

SS.

CWR03 · 12th December 2006, 01:50

An NTSC DVD rip will always be 29.97. AutoGK will usually decide correctly whether it needs IVTC or deinterlacing (or neither). As far as whether or not the output is 29.97 or 23.976 depends entirely on the source. IVTC'd will output 23.976; some deinterlaced content will still output 29.97.

If the input is bad IVTC and the output is 29.97, the output will look like crap. Without a sample of the source material and the AutoGK log it's impossible to tell what's wrong.

jggimi · 12th December 2006, 02:42

Think of it this way:

Content that was originally shot on film at 24fps was Telecined to 29.97 video. Inverse Telecine (IVTC) reverses most of that process, leaving 23.976fps.

Content originally shot with an NTSC video camera should be left at 29.97.

Stormshadow · 12th December 2006, 03:24

I didn't say that there was anything wrong...

I've just had several people say that 29.970 is bad ivtc and i just wanted that cleared...

Guest · 12th December 2006, 05:54

Quote:

Originally Posted by Stormshadow

I've just had several people say that 29.970 is bad ivtc

It makes no sense at all. If you knew what the words meant, you wouldn't need us to tell you that.

Stormshadow · 13th December 2006, 00:13

Well apperently i don't....

jggimi · 13th December 2006, 00:16

As I tried to explain above, Telecining is the process of converting 24fps film images to 29.97 video. Something that has been Telecined started out as film, then was transferred to NTSC.

I also tried to explain that Inverse Telecining is the reversal of that process. The acronym is IVTC.

This old tutorial will help: www.doom9.org/ivtc-tut.htm

12th December 2006, 01:10	#1 \| Link
Stormshadow Registered User Join Date: Dec 2006 Posts: 35	23.976 Vs. 29.970 I just wanted to see if people could clear something up for me... When ever i do a NTSC dvdrip then sometimes the resualt end up with a 29.970 framerate (as sourse of course) but i've had plenty of people telling be that when it uses that framerate then it's bad IVTC (everytime apperently, if i listen to them) I just wanted to know if thats true??? (and maby a reason) If yes is there a way to slow down the framerate to 23.976 no matter what in autogk??? I've played around with the hitten option but with no luck... SS.

12th December 2006, 01:50	#2 \| Link
CWR03 Custom User Title Join Date: Mar 2005 Posts: 3,733	An NTSC DVD rip will always be 29.97. AutoGK will usually decide correctly whether it needs IVTC or deinterlacing (or neither). As far as whether or not the output is 29.97 or 23.976 depends entirely on the source. IVTC'd will output 23.976; some deinterlaced content will still output 29.97. If the input is bad IVTC and the output is 29.97, the output will look like crap. Without a sample of the source material and the AutoGK log it's impossible to tell what's wrong.

12th December 2006, 02:42	#3 \| Link
jggimi Moderator Emeritus Join Date: Dec 2001 Location: The NW corner of Lake Erie Posts: 5,552	Think of it this way: Content that was originally shot on film at 24fps was Telecined to 29.97 video. Inverse Telecine (IVTC) reverses most of that process, leaving 23.976fps. Content originally shot with an NTSC video camera should be left at 29.97.

12th December 2006, 03:24	#4 \| Link
Stormshadow Registered User Join Date: Dec 2006 Posts: 35	I didn't say that there was anything wrong... I've just had several people say that 29.970 is bad ivtc and i just wanted that cleared...

13th December 2006, 00:13	#6 \| Link
Stormshadow Registered User Join Date: Dec 2006 Posts: 35	Well apperently i don't....

13th December 2006, 00:16	#7 \| Link
jggimi Moderator Emeritus Join Date: Dec 2001 Location: The NW corner of Lake Erie Posts: 5,552	As I tried to explain above, Telecining is the process of converting 24fps film images to 29.97 video. Something that has been Telecined started out as film, then was transferred to NTSC. I also tried to explain that Inverse Telecining is the reversal of that process. The acronym is IVTC. This old tutorial will help: www.doom9.org/ivtc-tut.htm