Framerate Problem

[benedict]

I have six AVI clips with different framerates that I want to merge; three at 9.990 fps and three at 14.985 fps. (I assume these were created by dropping frames from an initial 29.970 fps.) Simply changing the fps of one group or the other (or both) will cause speed-ups and/or slow-downs to one or both groups of clips, neither of which are acceptable in my final video. Obviously, I have to add or drop frames. I see several options here:

1) Repeat every second frame in the lower fps segment.

2) Drop every third frame in the higher fps segment.

Because of the initial low framerates on my input files however, I suspect that either of these is likely to increase the "jitter" already present in these files. To prevent that, my thought is to duplicate every frame on the higher fps file and triple every frame on the lower fps file.

Question: Does anyone know of software (freeware?) that can do this?

[DJ Bobo]

Use AviSynth

1) To get 29,97fps out of 9,99fps:

avisource("filename.avi")
selectevery(3,1,1,1,2,2,2,3,3,3)

2) To get 29,97fps out of 14,985fps:

avisource("filename.avi")
selectevery(2,1,1,2,2)

[benedict]

Cool! I knew there had to be something! Thanks! An additional question, if I might.

I'm not at all a newbie to computers. 17 years professional, and as many in a non-professional capacity. I'm not unfamiliar with scripting languages (although they used to go by other names). I checked out the AviSynth web site briefly also (and D/L'd already), and I'm sure I can find my answers there with some additional time and will certainly do some more reading. It's just that I'm so impatient when I get a new toy.

My question: Just what am I saying when I use the statements "selectevery(3,1,1,1,2,2,2,3,3,3)" or "selectevery(2,1,1,2,2)"? Does this have something to do with that half-frame stuff I've heard about? Exactly how are these decoded? I seem to be seeing a pattern in them but can't quite put my finger on it, and I so love to know exactly what I'm telling my machine to do. I've got a quite good feeling you know, and so I'd like to pick your brain a bit.

Anyways, thanks for the info so far. I had this stuff out on other forums for a week and more and got absolutely nothing.

P.S. Oh, yeah, one more quickie: Do I need to split off my audio tracks when I do that or does that all just fall back in OK?

[benedict]

Call me Dumbo!

It's right there: For every 3 frames, do frame1, frame1, frame1, frame2, frame2,...yadda, yadda, yadda. Nothing at all to do with half frames. I was trying to over-think it!

BTW: Spent a bit more with the AviSynth web site... Haven't even used it yet, but I'm already liking this toy a lot. Kind of like taking the training wheels off, isn't it?

[DJ Bobo]

As far as I know, there is no impact on audio synch, so you can keep the original audio as is (I tested this on a karaoke video, so I'm pretty sure of that).

Don't know if newer AviSynth versions can handle compressed audio well, but with version 1.05 I'm using, the audio won't be "seen" from AviSynth, so you'll have to extract the audio from the original AVI using AVI2WAV for example, then mux it with the newer (audioless) AVI files using VirtualDub.

[benedict]

Yeah, these clips all have MP3 audio and, from what I've read on Avisynth, that's a no-no even with the latest version..

I did find the Avisynth forum here, and I've been checking it out and trying to digest all this new stuff that they say to read first before posting there. Obviously, as a first-time scripter in that, I'll probably have my share of questions, and will post them there. Thanks for you help thus far.

By the way, from what I'm seeing, I can convert and join all of these in a single script. I can also add fade-in/out titles and credits and overlap those with the merged video itself, and that's what I want to end up with.

I'm thinking this might be a tad ambitious for a first script. But as I said above, I love new toys.
:p

[TactX]

benedict,

I really like your signature :)

[benedict]

@TactX

Actually, the signature that really got me was from the person who said he couldn't die until the government found a safe place to dispose of his liver! I asked if he could inform if there was extra room there when they found that place. He replied that they were considering rocketing it into the sun.

Finally, at last, we know what triggers the sun to become a "red giant"!