What is Interlaced Video? What is Pulldown? - digitalFAQ.com Forums [Archives]
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#1
06-10-2004, 07:54 AM
 khusru Free Member Join Date: Jan 2004 Location: Southgate, North London Posts: 263 Thanks: 0 Thanked 0 Times in 0 Posts
some very silly questions, but honestly i dont know the answers and would like to know as they are very basic things

1.what is interlaced video? and whats the difference between interlaced and de-interlaced?

2. what is pulldown (e.g3:2 pulldown) and what does it do?
Someday, 12:01 PM
 Site Staff / Ad Manager Join Date: Dec 2002 Posts: 42 Thanks: ∞ Thanked 42 Times in 42 Posts
#2
06-10-2004, 10:13 AM
 incredible Free Member Join Date: May 2003 Location: Germany Posts: 3,189 Thanks: 0 Thanked 0 Times in 0 Posts
A's:

1.
http://www.kvcd.net/forum/viewtopic.php?t=9808

2.

A 23.976 progressive source where most of the "movies" are shot on, cant be interpreted by a NTSC TV set directly as NTSC TV is showed at 29.97 interlaced.

So how can we get that 23.976 progressive to 29.97 interlaced?

Here I do quote the german "exotic interlacing" guide from Scharfis_brain

Code:
```Filmframe     A   B   C  D   E   F   G  H   I    J  K
Videofield1   A  B  B  C  D  E  F  F  G  H  I  J  J  K
Pairs          |  |/  /  /|   |  |/  /  /|   |  |/  /
Videofield2    A  B  C  D  D  E  F  G  H  H  I  J  K  L
Time        --p--p--i--i--p--p--p--i--i--p--p--p--i--i->```
Means, fields will be doubled and field shifted, and thats why a 29.97 comes out and why finally its combed (cause of dynamical field shifts).

You can do that with avisynth, BUT that would mean you also need to encode at 29.97 which in a case of real 23.976 sources WE DO NOT DO!

But we do keep 23.976 when encoding and the encoder applies a little information to the encoded stream which does say to the saplayer that the saplayer should perform that 3:2 Pulldown internally before sending it to the TVset. And thats called in TmpgEnc "Pulldown while play" or if cce or mencoder is used we do add to that 23.976 encoding the info afterwards using "pulldown.exe"
#3
06-10-2004, 12:33 PM
 khusru Free Member Join Date: Jan 2004 Location: Southgate, North London Posts: 263 Thanks: 0 Thanked 0 Times in 0 Posts
thanks pal, got it

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