Extreme DVD to DivX: Jason and the Argonauts (2000)

[CraigBee]

Extreme DVD to DivX: Jason and the Argonauts (2000)

The Challenge:

The challenge was Jason and the Argonauts (2000) (JatA2k). This is a great three-hour movie. Its also a crappy DVD. While it looks as good as one would expect on an interlaced NTSC television, it looks like crap on a progressive scan Television.

I had ripped this movie about a year ago when I was still using FlaskMPEG. I really like this movie, so I decided to try again. I made several attempts using DVD2AVI and VirtualDUB, but couldn’t improve on the old FlaskMPEG rip. So I decided to dive into AVISynth, and that made all the difference in the world.


The Format:

JatA2k has a very unique frame/field structure. When a film is converted to TV, it normally has 3 progressive frames and 2 interlaced frames. The 2 interlaced frames can be used to reconstruct 1 progressive frame. The converts the movie from 29.97fps interlace to 23.976fps progressive video. JatA2k has a very different frame/field structure that spans 6 frames (not 5 as would be normal). It looks like this:

Frame 1: Progressive
Frame 2: Progressive
Frame 3: Interlaced, field 2 motion blurred
Frame 4: Interlaced, field 2 motion blurred
Frame 5: Interlaced, field 1 motion blurred
Frame 6: Interlaced, field 1 motion blurred

Frames 1 and 2 are great progressive video. Things change in frame 3. Field 1 looks good, but field 2 is motion blurred with the next frame. This creates minor interlaced artifacts. Field 1 of frame 4 and field 2 of frame 5 can reconstruct to make a progressive frame. Field 2 of frame 4 and field 1 of frame 5 are motion blurred and create massive interlacing. Frame 6 is similar to frame 3, except that field 1 is motion blurred creating minor interlaced artifacts.


Why it is like that:

Her is my theory. The film was capture at full progressive 24fps, but the folks who did the conversion to DVD were monsters. First the film was speed up to 25fps to work on European DVDs. Next, the 25fps progressive film was converted to 29.97 fps to work on American televisions. This conversion was done by slowing the 25fps to 24.975fps, and then converting every 5 frames into 6 frames, thus expanding the movie to 29.97fps. 4 of the fields were motion blurred and interlaced to reduce the jerky effect of adding a frame to every 5 frames. The person that did this should be choked to death by his severed genitalia.


How to make DivX look better than the original DVD:

To make JatA2k look its best, I decided to reconvert the movie to 24.975fps by reconstructing the progressive frame hidden in frames 4 and 5. This is what the final structure looks like:

Frame 1: Progressive from original frame 1
Frame 2: Progressive from original frame 2
Frame 3: Deinterlaced from original frame 3
Frame 4: Progressive reconstruct from original frame 4 field 1 and frame 5 field 2
Frame 5: Deinterlaced from original frame 6

Here is the AVISynth script to perform this function:

# d2v reader
LoadPlugin("C:\DVDRips\AVISynth\MPEG2DEC.DLL")
mpeg2source("D:\RIP\Jason and the Argonauts\none.d2v")

# telecide and decimate
LoadPlugin("C:\DVDRips\AVISynth\Decomb.DLL")
Telecide(post=true)
Decimate(cycle=6)


Picture before and after:

Attached to this message are the 6 frames from the Original DVD and the 5 frames processed using the AVISynth script. I have left the pictures in their original 720x480 DVD size. For video encoding, the size was changed for proper 4:3 aspect ratio.


EDIT:

I am not sure if the attached picture is dislaying. If you'd like the picture, please PM or e-mail me. Especially if you can host the picture and link it below. The picture is 477k.

[OUTPinged_]

lol, i have had the same pattern with some other movie dvd a 3 months ago.

instead of decimating to 6, i was just using tmpeg's adaptation2 bottom field drop. :P

took me 4 hours to firuge this out.

looked crappy tho.

[Inindo]

Eh, I have a similar problem. This was viewed using AVISynth's Seperate fields in Virtualdub. I'm assuming that that a is the evin fields, while b is the odd fields.

Frame 1:Both fields good.
Frame 2:Both Fields good
Frame 3:Motion blur in a, can also be seen in b at a lesser extent
Frame 4:Both fields good. Previous motion blur is gone.
Frame 5:Field b bad, the ghost of the previous frame (motion)
Frame 6:Field a has the ghost of the previous frame, to a lesser extent
Frame 7:Field b has motion ghost
Frame 8:Motion made. a and b both have ghosts of previous frame
Frame 9:Good
Frame 10:a has ghost of upcoming frame, b has ghost of previous
Frame 11:both frames have ghosts of previous and upcoming
Frame 12:a is good, b has ghost of upcoming

Yada yada yada. It seems as if each individual field was blended with the fields in both the front and the back.

Whatdo I do with THIS monster?

[tenebrenz]

I have a few NTSC DVD which have gone through one of these nasty conversion. Unfortunately both were non-anamorphic 2.35:1 aswell which gave me very little resolution to play with. I don't think the video was slowed down to 24.975 before the conversion as CraigBee deducts because I think a realtime convertor was used. In the end I decided to use the ChangeFPS command to change to 30fps then did telecide() and decimate(6) to get to 25fps while leaving the audio untouched. The results were a little better than I expected and it played smooth on my monitor, stepping through there was only minor ghosting on some frames. Given the source I was quite pleased with the results.
Theoretically I suppose it would be possible for someone to code a filter that created new frames by subtracting part of the previous / following frame to create a current frame without a ghost, this would be slightly less difficult if the pattern stayed constant in groups of six but this sort of thing is likely to give anyone an extreme headache.