Jitter during transition in and out...

[Huntr777]

Hi all, here's a dome-scratcher for you...I am working with some Hi-Def footage that I transcoded into ProRes422. Using two video streams, main camera and close up cam. For some reason, any transition will have a little "jitter" to it when it comes in and out. I have been working with this kind of footage and never had this problem before. I tried using different transitions, copying to a different timeline, extending the transition...still does it. And this is after I have rendered it out...

Here is a clip to show you what I am talking about...you can clearly see the video jitter.

http://www.youtube.com/watch?v=1wljwHc9Amo

Any help is appreciated!

T

[lordsmurf]

You have repeated frames. I've seen this before.
What editor are you using?
It may be something as simple as a bad spot on the hard drive.

[Huntr777]

You have repeated frames. I've seen this before.
What editor are you using?
It may be something as simple as a bad spot on the hard drive.

i am using Final Cut Pro, latest version...so how do I get ride of these repeated frames?

[jagabo]

You have lots of missing frames too. I suspect your original video was h.264 encoded and when you converted to ProRes422 the video got messed up. Step though those ProRes422 clips frame by frame and see if there are any problems.

[Huntr777]

You have lots of missing frames too. I suspect your original video was h.264 encoded and when you converted to ProRes422 the video got messed up. Step though those ProRes422 clips frame by frame and see if there are any problems.

You are correct, the original was shot in H.264, then I transcoded to ProRes422 via MPEG Streamclip. I looked through the original footage and there are no missing frames though...

[Huntr777]

Just checked more footage from the same shooter (and transcoded out the same way). I am seeing the same problem again, so I don't think it's an error that was made in changing the footage over.

The question is this, how do I deal with this now that I have this problem?

[jagabo]

I was guessing the problem was in the h.264 to ProRes422 conversion because the out of order encoding and long GOPs of h.264 often lead to lost and duplicated frames. Whereas ProRes422 is all I frames so that's usually not an issue.

If you've ruled that out the problem must be happening in FCP. Are your sources all the same frame rate? Are some interlaced, some progressive?

[Huntr777]

If you've ruled that out the problem must be happening in FCP. Are your sources all the same frame rate? Are some interlaced, some progressive?

No, they are both the same frame rate and progressive

[jagabo]

they are both the same frame rate and progressive

It's hard to imagine how FCP could have screwed up so badly with all progressive intra frame sources.

[Huntr777]

they are both the same frame rate and progressive

It's hard to imagine how FCP could have screwed up so badly with all progressive intra frame sources.

Agreed. Now, do you have any idea how to stop it from happening?

[jagabo]

No ideas.

[Huntr777]

No ideas.

Here's the funny thing, before I render, the video is fine...after I render it, that's when the problems start...

[lordsmurf]

Internal hard drive, or something else as location of source?

[Huntr777]

Internal hard drive, or something else as location of source?

I am running off of an external Western Digital drive as I have done with the other projects and it's never been an issue.

I think what it comes down to is that the H.264 codec isn't really meant to be edited, it's more of a delivery codec...at least that's what Apple told me this morning.

But if you think something might work please, I'll try anything at this point

T

[jagabo]

I think what it comes down to is that the H.264 codec isn't really meant to be edited

That's true, but you've converted to ProRes422 and you claim there are no problems in the converted files. So h.264 is no longer an issue. FCP doesn't know your files were originally h.264.

[Huntr777]

Well, as Apple explained to me...yes and no. One has to keep in mind that H.264 is a very compressed codec. I can transcode it out to any other codec but the quality will never be there since the original is H264. Kind of like this, imagine if you crumple of a piece of paper, then uncrumple it. No matter how hard you try to get those folds out, they will still be there, same idea applies here. I believe that no matter how hard I try, that's going to happen with that footage.

In other words, if you want to shoot for editing later on, do not shoot in H264!

[jagabo]

Obviously. But that has nothing to do with your jerky video problem. Isn't that what you were complaining about?

[Huntr777]

OK, well the explanation I just got is the only thing I have to go on. So until somebody can give me a work-around...

[lordsmurf]

I've seen bad hard drives cause this.
The Final Cut buffer sucks, and will just repeat frames when it hits a bad spot that needs a re-read off a drive.

Copy the video to an internal hard drive. Or a better/different external.