Selecting Chapter Markers in VS10+

blplhp · Post by **blplhp** » Mon Sep 04, 2006 2:42 pm

When I am in Share|Create Disc|Add Chapters, I use the "jog wheel" to advance to the exact frame I want to mark as a chapter point, but the timecode display and the video preview screen "snap back" to a different timecode value, usually about a 1/2 second (15 frames) or so backward. So, then I move the jog wheel again, this time to a few frames in advance of my original selection, but the timecode display snaps back again to the same value as before. When I advance the jog wheel some more, sometimes it will snap forward about a 1/2 second or so. Is this normal? Why won't the program let me select the exact frame I want to use for my chapter marker? Is there a way of adjusting this time "interval" of selecting chapter markers?

Trevor Andrew · Post by **Trevor Andrew** » Mon Sep 04, 2006 2:59 pm

Hi

Sorry but my version also reacts the same. Version 9 was just the same.
Seems to move 13 frames from the last position????

I do not use chapters that much, i just live with the problem.

It has to be a bug of some kind.

I realise that this does not cure your problem, but you are not on your own.

Trevor

zehavi · Post by **zehavi** » Mon Sep 04, 2006 3:36 pm

Hi,
for this purpose I am using the "jog bar" to go approximately to the desired point, and then I am using the "go to next/previous frame" (under the jog bar) and it does the work.
Abraham

blplhp · Post by **blplhp** » Mon Sep 04, 2006 7:12 pm

Hi Zehavi,

Thanks for your suggestion, but it does not work for me. My timecode always snaps back 15 frames or snaps ahead 15 frames. It responds this way everytime I do the following:

1) use the jog wheel to dial in to the exact timecode setting I want.
2) if I press the play button and then click on the stop button, I see the timecode change settings.
3) if I click on the "Go to next/previous key frame" button, it too will snap back 15 frames or snap ahead 15 frames.
4) if I try to go directly into the timecode and change the number values directly, the timecode snaps back or snaps forward 15 or so frames
5) if I try to click on the little up arrows and down arrows in the timecode box, same thing happens, the timecode snaps back or forward about 15 or so frames.

There seems to be a built-in time interval of about 15 frames. And it will round to the nearest 15 frames. If I advance the timecode to 7 frames above the value it snaps back to, it will snap back to that same value again. If I advance the timecode to 8 frames above the value it snaps back to, then it will snap forward to the next 15 frame increment. It is not haphazard.

No matter which navigational tool button I use, I cannot get the program to stop on the exact frame I desire.

Are Steve J., Ken Berry, DVDDoug, Joe Louvar, Guy, BlackLab, Maddrummer3301 or anyone else on this forum having this same problem with their VS10+? I know that Trevor Andrew said above that his reacts the same way that mine does.

If so, then Ulead needs to be notified of this irritating bug.

Thanks.

Post by **Ron P.** » Mon Sep 04, 2006 7:26 pm

Your action is correct, it snaps to the Nearest Keyframe which apparently is 15. If you mouse over the < > advance to Next buttons, you will find it states Keyframe.

I just checked mine, and it responds the same.
Ron P.

blplhp · Post by **blplhp** » Mon Sep 04, 2006 7:33 pm

Ron,

You are exactly correct. The button is called "Go to next/previous keyframe", not "go to next frame".

So I guess VS10+ automatically sets this "Keyframe" to every 15 frames or so. Again, this needs to be fixed!!!

It should be "Go to next frame".

Thanks, Ron.

Post by **Ron P.** » Mon Sep 04, 2006 9:41 pm

Well I took a short 30 sec clip then rendered it, however before doing so I changed the I-frames from 15 to 1, just to see if VS was looking at the Iframes in the video clips. Guess what????? No such luck, it still uses the 15 frames, which is what the default Iframes are in DVD MPEG-2. So I suspect it is hardcoded into the program.

Ron P.

blplhp · Post by **blplhp** » Mon Sep 04, 2006 10:11 pm

Ron,

What are you referring to when you say "I-frames"? And where do you adjust it from 15 to 1?

Post by **Ken Berry** » Mon Sep 04, 2006 10:20 pm

I don't pretend to understand the technology involved, but I think this is all tied up with GOPs (Groups of Pictures) if the video you are editing is mpeg-2. A GOP starts (after a GOP header) with an I-frame or 'intra-frame' which doesn't need any reference to any other picture. It is followed by a sequence of P-frames (forward Predicted) and B-frames (Bi-directionally predicted). In a sequence which involves a low amount of motion, there will be more B-frames; in one with fast motion, there will be more P-frames. The size of a GOP can vary between programs, but I am guessing that in Ulead products it is set at 15, which seems to be a fairly average size.

Anyway, if this is indeed at the base of your problem, I don't think it can be called a bug -- it is just the nature of how mpeg-2s are constructed.

Indeed, I even suspect that the elusive GOP may be at the base of out of sync problems with mpeg-2s -- I think if a clip is cut in the middle of a GOP, the B or P frames on one side will no longer have their I-frame and in effect will be lost to the video stream, and this will throw out the audio stream by that many frames... If lots of editing cuts have been made, then the effect will be cumulative.

But then again, I could be completely wrong, and I for one would certainly welcome any clarification by people who know more about GOPs than me.