Title artifact on compression
 

I hope someone may be able to help me solve a small but aggrevating mystery. I have a short sequence that consists of some static titles over a still photo, followed by a scrolling title sequence over a slug, all composed in FCP 3. I exported as a FC movie and compressed in Compressor 1.1. I've tried compressing at 60 min. both in HQ (2 pass) and Quick (1 pass) modes. Everything is fine, except that the scrolling title sequence is preceded by a blip that shows the first line of the scrolling titles, completely visible at the bottom of the screen, for one frame, three frames before the same line appears as it should, scrolling onto the screen. Where did this one frame come from, and how can I get rid of it? It's a small, but unprofessional glitch to include in the final product. Any help would be appreciated (though I'd especially appreciate suggestions that don't involve a couple of hundred dollars of upgrade to a newer product that will no doubt have some other problem I'll find later).

Linc Kesler

I've had this same thing happen to me many times and it drives me crazy.

You're looking in the wrong place for the error. Its in your original FCP project. You may not notice it when watching your video on the computer screen, I never did. I wouldn't notice until I output to tape and then watched the tape. Once I got a real monitor as part of my setup, I could more easily see the flash when reviewing the video by playing the timeline.

There is a bug either in Calligraphy or Final Cut that causes this to happen. My solution was to go back into Calligraphy and trick it into thinking that I made a change (add a space then delete it) to cause a rerender of the title.

Sometimes it took a couple of tries to get it to rerender correctly.

Now whenever I use the scrolling text I pay VERY careful attention to the result.

Thanks, Mike. I tried your tactic of re-rendering, but with no success. I also stepped through the rendered source track a frame at a time and did not see the artifact. I exported it as a QT movie and stepped through it and saw no artifact there either (not surprising since it's the same source file). I think the artifact gets introduced visually not in the rendering, but in the MPEG compression, though it wouldn't surprise me if something in the encoded file sets the condition for it to appear. I wish I knew more about the file structure of both kinds of files.

I thought at one point that it might have something to do with the 3 kinds of frames found in the MPEG file, so I set a compression marker in the source file at the first frame in which the scrolling title appears, but that didn't seem to help.

If you have any further ideas, I'm all ears.

Thanks again,
Linc

I can guarantee you that the problem is not in the MPEG encoding because I saw it long before I started producing DVDs.

Do you have a broadcast monitor (or a TV) to watch the actual NTSC signal? Like I said, you will not see this in the Viewer or Canvas windows.

The more I think about this, the better my memory gets.

I'm just now remembering that the problem appears in only one of the interlaced frames and not the other, which is why you don't see it on the computer screen.

Another thing to try on the rerender. Go back to Calligraphy and add a blank line or two to the beginning of the scolling text. This may cause things to change enough to make the false half frame disappear. You will have to adjust your in point on the scrolling text to compensate for the two extra blank lines. In fact, moving the in point may be enough by itself. Did you try setting the in point of the scrolling text to be after the errant frame?

I have experienced the same problem in FCP 3, but as per Mike's experience, the problem always could be found in the Sequence in the Timeline after rendering. Re-rendering would occasionally fix it, though I swear it would reappear when restarting the project the next day. My final solution was to put a Slug, Shape, or Opacity change over the first few frames that were causing me the grief.

If, however, as Linc has suggested, the problem is absolutely not appearing until the MPeg compression, well I am stumped. Having never seen this I cannot even imagine a solution, except to go back and check all of the elements again. Ouch.

By the way, small consulation, but I have not had the same problems in FCP 4, but I don't often create scrolling text that way anymore.

Good point Duane, now that I recall, I haven't seen this issue in FCP 4 or later, at all.

Many thanks to all of you, but especially to you, Mike, both for the workaround and for the humbling elegance of your suggestion. I just inserted two blank lines. No doubt the bug, whatever it is, flashed the early frame again, but it was a blank one. Why didn't I think of that? Well, for me, that's evidence of the utility of forums such as this one.

I haven't yet returned to my main editing station to see if the artifact appears in the NTSC half-frame before compression, but I'm curious enough to do it when I can. In the meantime, thanks again for the help and the lesson in logic.

Linc

Glad I could help you.

And yes, this forum is wonderful. I check it every day.