Quick Question

[balbrain]

Hi I am trying to encode an pure NTSC Interlaced movie. I just wanted to confirm something real quick. In Doom9's GKnot guide initially in 'Step 4 : Find the right bitrate' he says :

"If you did not chose Force Film in DVD2AVI due to a too low film content you can perform IVTC during encoding. You'll activate IVTC upon saving the avs file (later on in the guide) but first you should already set FPS to 23.976 so that the correct number of frames for the resulting movie will be shown."

then in 'Step 7: Creating an Avisynth script' he says :

"If DVD2AVI showed your source as NTSC FILM below 95% you enable Inverse Telecine here and you must also change the framerate that you set in step 4."

Does he mean we have to chnage back from 23.976 to 29.97?

Also, If I use decomb for IVTC by editing the AVISynth Script (again as doom9's guide says) :

"While you did activate IVTC within GKnot for the compressability test you can disbable it again (but leave the fps untouched). "

Does he mean leaving it untouched at 23.976 or 29.97?

Thanx. It'd be great if you could incorporate these clarifications in the guides.

[llemor]

If I'm not mistaken, you are refering to a guide for "Gordian Knot/VirtualDub manual combo", isn't it?

If you intend to use DivX 5.02, I think it's better to use GKnot to encode your movie automatically and refer to updated GKnot's guide.

Anyway, here's my understanding:

"If DVD2AVI showed your source as NTSC FILM below 95% you enable Inverse Telecine here and you must also change the framerate that you set in step 4."
Does he mean we have to chnage back from 23.976 to 29.97?
Yes. I think setting first to 23.976 is to calculate the bitrate correctly.

"While you did activate IVTC within GKnot for the compressability test you can disbable it again (but leave the fps untouched). "
Does he mean leaving it untouched at 23.976 or 29.97?
My understanding, leaving untouched at 29.97. Disabling it will put InverseTelecine as comment line in the script. Then you have to add Decomb function. I think this is true for old version of GKnot 0.23.

@ Doom9: Please correct me if I'm wrong.

[Doom9]

first of all.. don't use the manual combo instructions anymore.. the only reason why the guide is still there is that I didn't want to dump the specific divx5 codec instructions.. who knows, maybe I can use them later on (too me rather long to write it all up).. but effectively with GKnot 0.26 there is no reason to resort to the manual way anymore.. it's based on an outdated GKnot version.

that being said the first quote is rather confusion.. you set it to 23.976fps right after loading the d2v and don't touch that value anymore. I couldn't locate the 2nd quote so I can't answer that. In fact I think you're mixing the two guides here as the manual combo makes no reference to the compressability check.

In GKnot 0.26 it's no longer necessary to adjust the fps, there's a switch in the encoder tab (explained in the guide) that will adjust the number of frames when you IVTC.. and that option is only selectable if you have activated IVTC so there's no chance of you accidentally enabling something that would screw up the bitrate calculation.

[balbrain]

Thanx a lot. BTW the second quote was from the link on "Performing better and faster IVTC"

--balbrain