Newbie problem re. interlacing

[Guest]

Archived from groups: rec.video.desktop (More info?)

Hey all,

I'm attempting to back up my "Strangers with Candy" DVDs to separate
AVI files-on-DVD for easier portability. However, I'm encountering
several issues (which are reminding me why I put this off for so
long), and I don't know what to do about 'em.

OK, so firstly, I rip the DVD (chapter by chapter, as chapters
correspond to episodes). I load the VOBs in DVD2AVI, and get a report
that the video is interlaced...no surprise there, as this is a NTSC
television show. I turn off FORCED FILM, and make my D2vs.

Here's the problem. I'm using GordionKnot to make my DivXes, and it
clearly shows "combing" in the frames. So I set up all my paremeters,
get to the encoding step, and tell it to Inverse Telecine. It gives me
a warning, but I hit OK and am on my merry well.

Thing is, the resultant file is not only far bigger than I specified
(250mb, as opposed to the 200mb I told it to create), but has very
"jumpy" video...it seems like frames are missing randomly.

I guess this might be a Gordionknot peculiarity, but as I've never
encoded TV shows before, I have NO idea what I'm doing wrong. Can
anybody help?

-D

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

On 31-Mar-2004, David Goodwin <ksg1-2@yifan.nyet> wrote:

> OK, so firstly, I rip the DVD (chapter by chapter, as chapters
> correspond to episodes). I load the VOBs in DVD2AVI, and get a report
> that the video is interlaced...no surprise there, as this is a NTSC
> television show. I turn off FORCED FILM, and make my D2vs.

That may be your first mistake. Just because a DVD is from a television show
doesn't mean that the VOB is interlaced. My Highlander DVDs (Season 1) were
originally shot on film (24fps) and telecined for broadcast. In fact, many
tv shows originate on film (Law & Order, NYPD Blue, etc). The production
company can either master the original 24P footage to DVD (most do) or
master the 29.97 footage to DVD (a waste of valuable disc space).

The DVD spec allows source material in 24P. The DVD player adds the 2:3
pulldown. This is simply the result of setting two flags on the DVD: TFF
(top field first) and RFF (repeat first field). The player adds the pulldown
and sends "interlaced NTSC" to the TV.

A "quck and dirty" way that I have of determining if the source MPG of a DVD
is 24P is this:

pause the DVD
advance forward one frame at a time
watching the "time counter" display, count as you advance one frame at a
time.
If you only advance 24 frames over the course of one second on the display,
there's a good chance the source MPG is 24P

This is not 100% relieable. Some DVD players don't advance "single frames"
precisely. Others might in fact advance the "NTSC frames" (i.e. 29.97). My
DVD play, however, advances "film frames" when using pause -> frame advance.


Try turning FORCED FILM on and see if you get any decent MPG. Or better yet,
use Vobrator or another VOB extractor to extract the source MPGs from the
VOBs. Then you'll know for certain whether the source material is 24P
(23.976) or 60i (29.97).


> Here's the problem. I'm using GordionKnot to make my DivXes, and it
> clearly shows "combing" in the frames. So I set up all my paremeters,
> get to the encoding step, and tell it to Inverse Telecine. It gives me
> a warning, but I hit OK and am on my merry well.

Inverse telecine is only used on 29.97 footage that is from a 24P source
(i.e. it does the same thing that FORCED FILM does, only in a different
way).

If, indeed, your source DVD *is* 29.97 "native" (meaning: from an NTSC
interlaced source) then inverse telecine is going to munge it up badly. You
should have heeded the warning. Turn it off and de-interlace instead.


> Thing is, the resultant file is not only far bigger than I specified
> (250mb, as opposed to the 200mb I told it to create), but has very
> "jumpy" video...it seems like frames are missing randomly.

Sounds like "Strangers With Candy" was shot on film and sourced to the DVD
as 24P. In this case, even if you used the best compressor in the world,
your file is going to be larger because you are compressing 30 interlaced
frames per second instead of 24 progressive frames per second. That's why
production houses use 24p source MPG for DVD when the source was shot on
film - because it makes no sense to add bits unnecessarily.


> I guess this might be a Gordionknot peculiarity, but as I've never
> encoded TV shows before, I have NO idea what I'm doing wrong. Can
> anybody help?

I haven't used GordianKnot, so I can't speak to that. However, I think you'd
be in better shape ripping the 24p MPGs from the VOBs using Vobrator and
re-encoding those with GordianKnot. You'll have smaller files and better
quality.

--
Chris

Munged email. To reply by email (each "word" a letter):
see jay bee are oh oh kay ee [AT] em ess en [DOT] see oh em

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

On Wed, 31 Mar 2004 20:27:35 GMT, "FlyByKnight"
<FlyByKnight@example.invalid> wrote:

>
>Try turning FORCED FILM on and see if you get any decent MPG. Or better yet,
>use Vobrator or another VOB extractor to extract the source MPGs from the
>VOBs. Then you'll know for certain whether the source material is 24P
>(23.976) or 60i (29.97).

I turned on Force Film, but I still get the obvious "combing" effect
in GordionKnot. I'm unsure exactly what to do about this (or whether I
have to encode it first to see if the problem can be fixed that way).

The doom9.org guides say to leave Forced Film off unless the frame
type is FILM above 95%.

I've never used Vobrator before. It'll tell me exactly what hte MPG
is? What do I do then?

>Inverse telecine is only used on 29.97 footage that is from a 24P source
>(i.e. it does the same thing that FORCED FILM does, only in a different
>way).

Ahh, OK.

>
>If, indeed, your source DVD *is* 29.97 "native" (meaning: from an NTSC
>interlaced source) then inverse telecine is going to munge it up badly. You
>should have heeded the warning. Turn it off and de-interlace instead.
>

Wait, what's the difference between IVTC and deinterlacing?

>
>Sounds like "Strangers With Candy" was shot on film and sourced to the DVD
>as 24P. In this case, even if you used the best compressor in the world,
>your file is going to be larger because you are compressing 30 interlaced
>frames per second instead of 24 progressive frames per second. That's why
>production houses use 24p source MPG for DVD when the source was shot on
>film - because it makes no sense to add bits unnecessarily.

GordionKnot has an option where you tell it the source-file size
"goal," and it determines compressability, etc. accordingly. I've only
ever encoded movies before, and it's never been "off" quite like this.
If I turn IVTC off, will it hit the mark?

>
>I haven't used GordianKnot, so I can't speak to that. However, I think you'd
>be in better shape ripping the 24p MPGs from the VOBs using Vobrator and
>re-encoding those with GordianKnot. You'll have smaller files and better
>quality.


Can those MPGs I get be frameserved in? I'm really very new to video
encoding, and my problem is that while I understand the basic process,
the intricacies are still somewhat lost on me. For example, every
single guide I find is geared towards DivX-ing movies...nobody bothers
talking about television shows on DVD, and the interlacing issue seems
to be tremendously complicated. I just have *no* idea what to do, as
my attempt with IVTC failed miserably and everything else I've tried
in the interim doesn't get rid of the "combing" effect.



-D

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

On Wed, 31 Mar 2004 20:27:35 GMT, "FlyByKnight"
<FlyByKnight@example.invalid> wrote:


>
>pause the DVD
>advance forward one frame at a time
>watching the "time counter" display, count as you advance one frame at a
>time.
>If you only advance 24 frames over the course of one second on the display,
>there's a good chance the source MPG is 24P
>


FWIW, PowerDVD went through 29 frames for the one second on the
display.



-D

 

[Brian]

Archived from groups: rec.video.desktop (More info?)

David Goodwin <ksg1-2@yifan.nyet> wrote:

>Hey all,
>
>I'm attempting to back up my "Strangers with Candy" DVDs to separate
>AVI files-on-DVD for easier portability. However, I'm encountering
>several issues (which are reminding me why I put this off for so
>long), and I don't know what to do about 'em.
>
>OK, so firstly, I rip the DVD (chapter by chapter, as chapters
>correspond to episodes). I load the VOBs in DVD2AVI, and get a report
>that the video is interlaced...no surprise there, as this is a NTSC
>television show. I turn off FORCED FILM, and make my D2vs.
>
>Here's the problem. I'm using GordionKnot to make my DivXes, and it
>clearly shows "combing" in the frames. So I set up all my paremeters,
>get to the encoding step, and tell it to Inverse Telecine. It gives me
>a warning, but I hit OK and am on my merry well.
>
>Thing is, the resultant file is not only far bigger than I specified
>(250mb, as opposed to the 200mb I told it to create), but has very
>"jumpy" video...it seems like frames are missing randomly.
>
>I guess this might be a Gordionknot peculiarity, but as I've never
>encoded TV shows before, I have NO idea what I'm doing wrong. Can
>anybody help?
>
>-D

Take a look at the site www.dvdrhelp.com they have some great
tutorials on ripping DVD's etc

Regards Brian

 

[Guest]

Archived from groups: rec.video.desktop (More info?)

On Thu, 01 Apr 2004 11:58:41 +1200, Brian <nospam@anywhere.com> wrote:


>
>Take a look at the site www.dvdrhelp.com they have some great
>tutorials on ripping DVD's etc
>
>Regards Brian


They do, but none addresses my problem.

Here's the maddening thing: I think I found what can fix it. In
TMPGenc, the "Even Field Deinterlace" option clears up the picture
almost perfectly. The thing is, TMPGenc can't encode to DivX! Is there
any way I can use this filter outside of that program?



-D