Render is 1 Frame Early

cold-ones wrote on 2/9/2009, 8:58 AM
Usually, when I export a portion of a program into AVI or Mpeg the render is frame accurate. But if I export to QuickTIme or Windows Media, the render begins with the frame immediately PRIOR to the desired first frame.

All events on the timelines are Quantized to Frame, and I've tried different ways to select the portion I want to render (either by selecting part of the timeline, or between markers, or a region) to no avail.

I've also turned on the "Show Unquantized Event Start" & "Show Unquantized Event End" in the internal preferences, thinking that maybe the events weren't Quantized. All was OK. But I noticed that when I reimport a rendered WMV file back into the timeline to look at it, not only is the first frame early but the movie's end point is highlighted as an Unquantized Event End.

Ever seen this?

Comments

megabit wrote on 2/9/2009, 10:54 AM
Yes - exactly the same happened to me when I wanted to render out a small portion of my lengthy project into a piece for Vimeo.

I had to physically copy the desired fragment to separate tracks to get rid of the early frames (I'm not sure whether it was exactly 1 frame or more).

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cold-ones wrote on 2/10/2009, 7:34 AM
I think it's one frame, although I'm getting a bit punchy with all the trials of what should be a no-brainer. megabit, I agree---I've seen a similar odd behavior with mp4 renders, which when played under QuickTime show a white flash frame at the end of each movie. ??Perhaps because it's starting too early??

Another surprise: I used "Edit Details" to add one frame to each Region starting point, just typed in the next frame number. Lo & behold the Region marker moved slightly MORE than a frame, putting the marker in sub-frame limbo.

I have snapping enabled, etc. Is there any way to make Regions & Markers snap to frames?
cold-ones wrote on 2/11/2009, 7:10 AM
Kudos to Randall Campbell (he of "Veggie Toolkit" fame) for figuring this one out: the culprit was my render settings for wmv & mp4 files. If their fps doesn't exactly match the timeline that's spawning them, you'll get frame mismatches (in my case, the timeline was 29.97 fps and the wmv render setting was 30 fps).

Now I can use the Veggie Toolkit Multi-Render (BTW, these tools are a must-have, I use them every day) and make frame-accurate compressed movies.

One thing that remains unexplained is the weird behavior of markers when you increment them by one frame in Edit Details, they get placed on the timeline in weird sub-frame areas. Also, while the resulting movies now start at the correct frame, their duration is slightly longer (perhaps 1/5 of a frame?) than it should be (it's flagged as having an Unquantized end point). Two for another day...
fldave wrote on 2/11/2009, 8:10 AM
Thank you! I thought is was some weird V8 thing. I started using V8 recently after an 8 month project in V7. My first Batch Render to avi of several regions was fine, but my QT MOV renders included frames from other regions.

I must have had the MOV set to 30 instead of 29.97. Thanks for the explanation!