Media Trimming

How does the media trimming exaclty work within a timeline? I am having issues using the start point and media property start time to dial effects in. My files all are the same length as the timline so I assume I would be able to adjust all the properties accordingly but that does not work. 

Example. Effect is at 19.11 on the media file. I set the start point to 19.11 and the media property start to 19.11 but nothing happens. If I reset all the properties or re ad the file to the layer its fine. The problem is then any other effects below will not happen. 

Any one have thoughts?

  • Could you post a snapshot of your timeline?

  • This timeline is for sporting lights at an arena. As youll see there are several different Pixel Matrices. I built all the media files in Adobe After Effects at the same length as the timeline to correspond to a video with small h.264 mp4 files that match the same size as the Pixel Matrix layer in Mosaic. Those files just contain a white background to flash and fade a specific times.Since layering comes into play in Mosaic I need to trim these files down specific time codes. At this point I could have probably just built the same effects in mosaic but I am stubborn and want to figure this out. 

  • I think I understand. I've tried several different ways and so far I'm not recreating. Lemme see if I can repeat back correctly...

    The master video you are syncing to is (let's say) 60 seconds. You made several movie files that are all 60 seconds long. One of these videos has a white flash at 19.11seconds. So you dragged that movie to 19.11 in your timeline, then made the clip also start at 19.11 in its content.

    So my question now is, is there something else that is being output to those fixtures when that clip at 19.11 starts that it layers on top of? Or is this the only thing playing on those fixtures?

    Clip started at 0.00

    Clip started at 0.00 - Playback paused at 5.00, no change to clip start time

    Clip started at 5.00 - Playback paused at 5.00, clip start time changed to 5.00

  • Ok here is my problem. Note that 19.11 is actually before the effect and the effect is around 19.12. 

    Here is the video clip as a whole. 

    You can see the top left lights are now white so they are on. 

    Now when I trim the Start time to 19.11 they go off. I also trim the end so it does not effect fixtures after this effect. 

    If I set the media property to 19.11 they are still off. 

    If I set the Media property to 20.11 like magic they are on. 

    That is what I am confused by. Why is it right if when added from start to end, but when you go to trim the file it messes it all up? 

  • Ah ha. It's because your timeline is set to a timecode timeline. So the Start time is represented in frames and your media start time is represented in 1/100ths.

  • So set the media start time to 19.33 (if you have your timeline set to 30fps)

  • How does the math come out to 19.33? Also that didnt light anything. 

  • 100/30fps =.03 . 11 frames x .03. But again that's assuming you selected SMPTE30 or NTSC30. Change your timeline to Internal and it should work with the numbers you originally put in.

  • Thank you!

    The original numbers are all timecode from After Effects. So the 19.11 is 19 seconds and 11 frames. I also checked and I accidentally used 29.97 and not 30 FPS, so that will add some more wrinkles... Guess I will have to spend some time tweaking. 

  • Right on. Welcome!

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