Resulting xvid .avi is 23.98 fps from a DVD NTSC which is 29.97 fps with Auto GK 2.4!

[nukesgoboom]

Using Auto GK 2.4, i encoded Apocalypse Now Redux which was a NTSC DVD so it was 29.97 fps, but the resulting xvid .avi has 23.98 fps. why is this? is this some sort of de-interlacing technique? the file looks good, i just dont understand why the frame rate was changed. does it have anything to do with the instructed file size? i told auto GK 2.4 to use 1390 MB and it was nearly exactly that. the movie is 3 hours and 22 minutes long.

why would auto gk 2.4 lower the source 29.97 fps to 23.98 fps?

[buzzqw]

search "Force Film"

BHH

[Blue_MiSfit]

Right. :search: !

In a nutshell - it's a hollywood movie, which means it was shot at 24fps on film. Pulldown fakes 29.97fps so that it will look right on an NTSC tv, which operates at 60hz (29.97fps). Soft pulldown is easy to remove and recover the original 24fps, as it's just a flag in the MPEG-2 bitstream. It's a very good thing, as encoding at 23.98 means more bits/pixel*frame.

~MiSfit

[jggimi]

See www.doom9.org/ivtc-tut.htm for more info; the software discussed there is out of date, but the information about film and video will be very helpful.

[nukesgoboom]

thank you for the link to the ivtc it was a great read. thank you guys for replying as well. there are only a few issues i am confused about still.

so films played at the cinema are 24 fps because its a standard of film. what is magic about 24 fps? why was that number chosen?

what about movies that are done entirely on the computer, such as Over The Hedge or The Incredibles? no physical camera is used, all images are rendered by software. are they naturally 24 fps when all the footage is ready for the transfer from the digital realm to film?

what if i recorded some gameplay footage using fraps on quake 3, using 30 fps. then i convert the footage to dvd NTSC format which is 29.97 fps, but if i used auto gk to convert back to a .avi, would it be down framed to 23.98 fps?

is that because DVD video is actually is 23.98 fps with a flag to fake the 29.97 fps?

[CWR03]

what about movies that are done entirely on the computer, such as Over The Hedge or The Incredibles? no physical camera is used, all images are rendered by software. are they naturally 24 fps when all the footage is ready for the transfer from the digital realm to film?
For now, because HD projectors are too expensive and aren't as bright as film, movies like that are transferred to film for theaters. That makes them no different than normal movies as far as framerate is concerned.
what if i recorded some gameplay footage using fraps on quake 3, using 30 fps. then i convert the footage to dvd NTSC format which is 29.97 fps, but if i used auto gk to convert back to a .avi, would it be down framed to 23.98 fps?
AutoGK determines what it needs by determining whether it's telecined or interlaced. If you input a non-interlaced 29.97 file, it seen no need to use deinterlace or IVTC on it, so you'll get the same 29.97 framerate output.
is that because DVD video is actually is 23.98 fps with a flag to fake the 29.97 fps?
Most films on DVD are that way, but there are other materials that are different. Videotape on DVD is 29.976. Interlaced and telecined have the lines "mixed" horizontally and they have to be unmixed. There are hybrid sources that have both, and AutoGK usually does a good job of determining which parts need what processing.

[nukesgoboom]

astonishing that auto gk can automatically detect those parameters from a dvd! im shocked. i had no idea that level of complexity was comming into play with the frame rate.

thank you for showing me the answer to some big mysteries that i had not understood!

[BigDid]

astonishing that auto gk can automatically detect those parameters from a dvd! ...
:)
Even if not perfect, AGK is mature. I suppose Len0x having reached his personal(s) goals with his program has just ....stopped

Let's do with what we have ;)

Did

[CWR03]

astonishing that auto gk can automatically detect those parameters from a dvd! im shocked.
To be accurate, it's DGIndex that determines the needs of the video.

[Blue_MiSfit]

Yeah, open source is pretty cool. Anyone try using Apple's Cinema Tools (their pulldown / telecine / inverse telecine program)? It's a joke!