Media FX keyframe bug?

fausseplanete wrote on 3/23/2009, 2:00 AM
Location of live event was a conference room with large glass roof on a sunny day with increasing patchy cloud. Multicamera multi-hour shoot. Kept cams on manual exposure with occasional adjustments as the cloud increased and average light level and colour temperature diminished during the day.

So now, in post (Vegas), wanted to apply keyframed Media FX to vary levels and colour compensation over time. BUT Media FX keyframing went buggy once I had more than 2 keyframes. A total show-stopper for this easy way, instead had to individually correct each Event (in a Vegas MultiCam track) by Event FX. Unable to workaround by color correcting the source media to intermediates due to lack of disk space and anyway needed to see the result in context (to check the multi cams match up at each stage). BIG shame therefore. Hours passed...

Anyone encountered this, or know how to work around it?

Comments

farss wrote on 3/23/2009, 2:29 AM
"Media FX keyframing went buggy once I had more than 2 keyframes."

Can you elaborate on this?

Keyframes can appear to be doing many "buggy" things however everytime I think something wierd is going on I step back a bit, check exactly what is going on and then realise the bug is in my head.

Bob.
fausseplanete wrote on 3/23/2009, 6:28 PM
Bob,

The problem can be replicated as follows:

First create a fresh Project, add to it a proper video clip (not a Generated Media) of about an hour (don't know if shorter will suffice). I used an HDV (m2t) clip from a Z1.

Event > RtClk > MediaFX > Add ColorCurves.

Unlike EventFX, MediaFX doesn't have a "Lock to Cursor" mode, i.e. the little button for that (at bottom-left of MediaFX dialog) is disabled. Not a bug but a feature I guess, though nevertheless an impediment, and maybe tends to discourage the use of more than one keyframe in a MediaFX. My workaround is to position main timeline cursor then add a keyframe (in the MediaFX dialog's mini-timeline) with a ridiculous setting then drag the keyframe back and forth in time until the obviousness of the FX is at maximum (e.g. as seen in Preview or, more accurately, on Scopes). Then the keyframe is approximately sync'd with the timeline cursor. Better than nothing.

I mention ColorCurves because I tend to use that rather than Levels when crushing might otherwise occur. Like where half the (live show, uncontrolled) room was in sunlight whereas the speaker was in shadow. Needs keyframing over time because cloud came and went. Ideally done at MediaFX level instead of EventFX because it is a multicam shoot and there are many between-camera cuts hence many Events. And I might want to refine some of these cuts later and not have to worry about missing such FX off some of the new Events so created.

In the MediaFX mini-timeline, first place and adjust one ColorCurves keyframe at the start, another at the end. Next in the main project timeline put the cursor just under (deliberately) half-way along the Event and in the MediaFX's timeline similarly put it in about the middle. Twiddle the ColorCurves tangent control so as to add another keyframe there. Following my previously explained workaround, twiddle it to a ridiculous level, then slide its corresponding keyframe (the middle one) about in time to find the position that syncs with the main timeline cursor. BUT although the main timeline cursor was (deliberately) left of centre, the matching position in the MediaFX dialog's timeline is most definitely right of centre. So something's wrong straight away.

Next put the timeline cursor at the end of the Event and the MediaFX cursor at the final keyframe (already there) at the end of its mini-timeline. BUT adjusting that keyframe no longer has any visible effect.

Incidentally I just tried the same overall experiment with Levels instead of ColorCurves and the same things happened.

David
farss wrote on 3/23/2009, 7:40 PM
I suspect the problem starts with trying to keyframe a MediaFX.
After some mental gymnastics I think I can see why we're not directly offered the option of doing that.
Say we have a 60min clip, put a keyframe at the beginning and end of it. We only use the first minute of it. Then we do a Save With Media. The media that held the end keyframe is gone. One could be created at the end of the new 1 minute clip by interpolation I guess but that's a lot more coding.

From memory I recall that US's multicam lets you add EventFXs that are carried over after you do the mulitcam edit and collapse all the tracks into one. I don't know about the new multicam capability in Vegas as I've not had cause to use it.

I can appreciate why you're trying to do what you're doing, my approach has been similar as well even though it breaks the traditional workflow of edit first then grade. I hope somebody else can recommend a workflow for your kind of situation that works smoothly as so far all I've been able to tell you is why I don't think what you're trying to get to work will work.

Bob.