Image/movie Node basics #b3d


Have you ever felt the life draining out of yourself, as if you are trying to struggle up the side of the Sarlacc Pit on Tatooine?

This is how I feel, trying in vain to make Blender’s image/movie node match with the VSE timeline. The reason for my angst is Blender’s naming of frame values. Specifically the naming of one particular value … Start Frame.

Start Frame appears in both the Image node and in the VSE strip properties but it is calculated differently.

The VSE Start Frame is the value of a strip’s location on the timeline, without the strip being trimmed. There is another value that offsets the beginning, or trim value, of the strip and its called Trim Duration (Hard or Soft).

The Compositor Start Frame is the value of the clip’s location in the scene timeline (that you visualize) including the trim value. And to do that you’ll need the right formula.


Add an “Input Image” node and use Movie as the source.

Frames will give you control on the source’s duration (in frames): How many frames do you want to use? Playback will repeat the last frame unless you choose Cyclic* (see below)

Start Frame is the frame in the scene at which the video clip will start playing.

Offset allows you to select the first frame of the video source.

Cyclic* will make the cycle of frames start over. If you want to hold a frame, before or after the specified number of frames or freeze a frame you would need to disable this box.

Auto Refresh if disabled you may not see the sequence of images change.

WHY are they called the same thing if they don’t work the same?!!!!!!!

So if you would like to replicate a VSE edit in the node editor then you can adjust the :

length, frame start and offset

Here is a node mimicking a VSE edit:

Replicate a trimmed VSE strip in nodes
  • VSE Length = Node Frames (duration in frames eg.73)
  • VSE Start Frame = Node Start Frame (Position on timeline + Offset eg. 73+(526), note that this could have a negative number for start value when the strip begins before zero on the timeline)
  • VSE Trim Duration “START” = Node Offset (Trimmed clip start eg. 526)

Below are a range of examples with matching VSE and Node values.


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