Markers Move When Importing VMS File To DVDAS

BobWard wrote on 9/26/2010, 9:47 AM

I set markers in my movie project in VMS10 to identify different scenes. I rendered the VMS project to MPEG-2 and AC3 and opened the file in DVD AS 5.0.

It appears that the markers that I set in VMS10 are at slightly different locations when viewed in DVD AS.

Has anyone else noticed this? If so, is there a procedure to insure that the marker locations will not move when the rendered VMS files are opened in DVD AS?

Bob

Comments

Former user wrote on 9/26/2010, 11:00 AM

If the markers are moving only a few frames, then this is probably the result of the markers moving to an I-frame. In Vegas pro there is an option to create an iframe at the marker point when rendering to an MPEG file. I don't know if VMS supports this feature.

The Chapter mark always has to be on an iFrame and if you can't control that with VMS, you have to plan on it being off a bit.

Dave T2

BobWard wrote on 9/26/2010, 12:47 PM

Thanks for the response Dave. I have no idea what an I-frame is and a word search in the VMS10 Help document did not reveal the phrase "I-Frame".

However, in the VMS10 "Render As" diaglog box for MPEG-2 files, there is an option under the Custom tab to "Insert I-frames at markers". This box is checked as a default setting. So I assume an I-frame got inserted at each marker when I rendered the file in VMS 10.

However, something must have transpired in the import to DVD AS to cause the markers to move just a little bit from where they were in VMS. Could that simply be due to the file conversion to MPEG-2, i.e., maybe the frame count is slightly different in the rendered file?

Bob

musicvid10 wrote on 9/26/2010, 2:20 PM

Bob, an I-frame is a reference frame.

Former user wrote on 9/27/2010, 12:44 PM

No, the frame count should be identical. If the chapter is moving from your selected point and the iFrame option is checked, then it should be in the same spot you select when you create the timeline.

I don't know of anything reason it would move. Maybe someone else more familiar with VMS could offer some information.

Dave T2

musicvid10 wrote on 9/27/2010, 5:15 PM

I have had several instances where DVDA added a few frames at the end of the timeline, probably to end up perfectly with the audio. I also noticed that my markers were off a frame or two, but moving them to the nearest I-frame was enough for my purposes. DVDA may be moving the GOP indexes around a bit to keep audio sync, but that is just a silly guess.

Whether frame-accurate chapter points are always possible in DVDA, and what methods are necessary to accomplish them, would take a bit of testing, but if someone would like to undertake it, I would enjoy hearing the results.