Changing Frame Rate Of A Non-MPEG For Convention Submission?

[Melichan923]

I will be submitting to an AMV contest this year which recently changed it's rules a little. Normally, a DVD ready MPEG was requested but this year the convention asks for videos to be in AVI format. I actually prefer this since it's the higher quality option if I can send it as a lossless file, but I have a few questions on how to get it right. I'd prefer to ask all you smart people here before I go bombarding the poor contest coordinator with tons of questions.

The Convention rules are:
- 720x480 pixels in size
- Frame rate of 29.97fps (NTSC)
- Audio at 48000 Khz
- Video must be NTSC (not PAL or SECAM)

My exported video from Sony Vegas is:
- 848x480, Anamorphic
- Frame Rate of 23.976 (IVTC)
- Audio 44100Hz

I think all formats will be re-encoded to MPEG for the convention showing. Usually, I use TMPGEnc and the Otaku Video profile like mentioned here to convert for conventions and that calls for just applying a simple 3:2 pulldown flag to change the framerate. I looked up ways on how to change the frame rate of an AVI from 23.976fps to 29.97fps while keeping audio synced and I found this in the guides:

Code: Select all

AssumeFrameBased
ComplementParity
SeparateFields
SelectEvery(8, 0,1, 2,3,2, 5,4, 7,6,7)

(It's for top field first because that is the most common, if I remember correctly.)

But changing the frame rate this way makes me slightly nervous for some reason. I'm not very knowledgeable in this area and I probably have the wrong idea, but how will I be able to tell that the interlacing won't be embedded in the file when the convention re-converts it? I'm just worried that if it gets into the contest, there will be noticeable interlacing or even jumpy motion on the screen when I convert this way. Maybe I'm just being paranoid, but I'm in a stressed out AMV-editing streak and I don't want anything to go wrong.

Below is going to be my full script for their specifications. Could someone please say if it looks correct or not or if I should change anything?:

AviSource("C:\Documents and Settings\Desktop\ToConvert.avi")
Lanczos4Resize(720,352)
AddBorders(0,64,0,64)
SSRC(48000)
AssumeFrameBased
ComplementParity
SeparateFields
SelectEvery(8, 0,1, 2,3,2, 5,4, 7,6,7)
Weave

Thanks for reading and I look forward to your replies.

[Scintilla]

First off, let me say that those lines should be AssumeFrameBased(), ComplementParity(), SeparateFields(), and Weave().

But changing the frame rate this way makes me slightly nervous for some reason. I'm not very knowledgeable in this area and I probably have the wrong idea, but how will I be able to tell that the interlacing won't be embedded in the file when the convention re-converts it?

The interlacing WILL be embedded in the file. The lines you're adding are manually telecining the footage from progressive 23.976 to interlaced 29.97. The idea is that, if the video is to be played back on an interlaced display (such as a standard-def television set), this will provide the best result.

That said, I would definitely ask the contest coordinator what to do. They may be willing to take your 23.976fps file and do the conversion themselves, or they may tell you what field order they prefer for interlaced video.

[Melichan923]

Again thank you very much for much for replying to my question, Scintilla! You are always helping me out and I appreciate it a lot!

First off, let me say that those lines should be AssumeFrameBased(), ComplementParity(), SeparateFields(), and Weave().

Oh, right! *Smacks self* How could I not put in the ()'s!? I just copied it off the page I found it on.

The interlacing WILL be embedded in the file. The lines you're adding are manually telecining the footage from progressive 23.976 to interlaced 29.97. The idea is that, if the video is to be played back on an interlaced display (such as a standard-def television set), this will provide the best result.

That said, I would definitely ask the contest coordinator what to do. They may be willing to take your 23.976fps file and do the conversion themselves, or they may tell you what field order they prefer for interlaced video.

That is probably the best thing to do. I was browsing the conventions forums after I posted and I think I may have found the answer and that they will, but I'll play it safe and re-ask them in a PM. I'd like to leave them with less work as possible if I can. All those videos sent in!

Even if I may not use it for this Con, this information is good to know for future reference.

[Qyot27]

Note: if they accept progressive video, then instead of telecining the file, you could just add ChangeFPS(29.97), since ChangeFPS duplicates frames to achieve the result. You'd have to eyeball it to see if it introduces jerky motion, though.

[Melichan923]

Note: if they accept progressive video, then instead of telecining the file, you could just add ChangeFPS(29.97), since ChangeFPS duplicates frames to achieve the result. You'd have to eyeball it to see if it introduces jerky motion, though.

I'll try that out if they accept it. Thanks!