making PAL DVD from AVI when frame rate is 29.970 fps

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-- making PAL DVD from AVI when frame rate is 29.970 fps

Posted by djdawn on Apr-28-2004 14:56:

making PAL DVD from AVI when frame rate is 29.970 fps

title says it all...possible?

got most of the necessary tools and I'm not completely unfamiliar with stuff like this.

thx!

Posted by djdawn on Apr-29-2004 06:52:

nevermind, found this at doom9

- A Tale by Herr MACHiAVELLi -

+ Version 0.1 +

I decided to write down some notes on the encoding of silents and fucked up PAL or NTSC region
DVDs, since there have been some problems lately and people couldn't find out how to fix them.
What kind of fucked up PAL/NTSC DVDs do I have in mind? Only one category: bad mastered PAL ->
NTSC or NTSC -> PAL conversions. An extension of the theory applied on "restoring" this kind
of fuck-ups lead me to developing a method to encode silents.

Some notes before we start with the real job:
- PAL standard is 25 fps
- NTSC standard is 29.97 fps, but I round it up to 30 fps (easier calculations)
- FILM is 23.976 fps, and I rounded this up to 24 fps (for easier calculations)
- I assume that people know the basics behind telecining 24 -> 30 fps
- I further assume that you are aware of encoding utils as avisynth (avs) and Decomb. If not,
I advise to read things over at doom9's utopia (www.doom9.org). It should be explicitly
noted that the methods only work for Decomb (at least, that's the only thing I found
capable of doing the job right). Consequently, all presented methods are described for
avs in combination with Decomb.
- I use certain examples from the "DivX ;-) SCENE HiSTORY" to illustrate certain aspects of
the theory and its application in practice. These groups are not targeted whatsoever: I
don't have the intention to praise them, nor to bash them. They are just examples... :P
- It seems that up till now, few encoders are aware of what will be described in the following
text. I can only hope that those who are really interested in this technique, take the
effort and TIME to experiment, and that their experience will lead to an enhancement of
the DivX ;-) scene quality.

Table of contents:

1. Introduction
2. Bad NTSC -> PAL conversion
3. Bad PAL -> NTSC conversion
4. The art of encoding silents
5. Conclusion & final notes

1. iNTRODUCTiON
---------------

The latest TDX rules (TDX 2002) contain this small line: "MUST be as close to original
source framerate as possible." A simple soul will immediately think of the inverse telecining
(IVTC) that should be applied when dealing with NTSC DVDs (at least, if the DVD source is
not 100% NTSC or hybrid). But there are other possible scenarios, more exotic and pretty
rare, but they exist ergo encoded and kicked on somebody's ftp. These scenarios are worked
out in the following chapters...

2. BAD NTSC -> PAL CONVERSiON
-----------------------------

The normal case scenario for converting NTSC to PAL is as follows: The 30 fps NTSC source is
IVTCed to 24 fps FILM. The FILM source is speeded up to 25 fps, which complies to the PAL
standards. This works well if the source is telecined FILM. If the source is native NTSC, id
est shot at 30 fps (most notably concerts and TV shows), then IVTCing of the source is off
course impossible (this would give very choppy results).

Good conversion methods:
- NTSC -> FILM -> PAL => IVTCing of the NTSC source, followed by speeding up the FILM source
by 1 fps. This speeding up process causes a difference in runtime
between movies shown on TV in NTSC and PAL regions. This difference
amounts a factor 25/23.97; check the runtime difference for The
Matrix for instance: 136 minutes in the USA, 131 minutes in Germany.
Also note that the majority of companies have the FILM source available,
so they won't have to IVTC some obscure NTSC discs.
- NTSC(native) -> PAL => Since native NTSC cannot be IVTCed to obtain PAL, frames will have to
be merged together. Decimation of 5 fps is impossible, since it would
result in choppy movies. Merging of some frames can result in less
frames, but you'll have ghosting effects. Some good examples are the
Star Trek Enterprise DVDs. Those DVDs are hybrids in NTSC regions
(mixed FILM and native NTSC parts), but are 25 fps in PAL regions.
The parts where native NTSC parts occured on NTSC discs show clearly
ghosting artefacts on PAL discs. Anyway, there isn't a better method
to convert native NTSC to PAL.

maybe I'll just make a NTSC DVD and buy a player that plays PAL & NTSC!!!