Why does the frame range setting behave differently when using multiple scenes in the Video Sequence Editor?

Question

I am having trouble to understand how Render > Dimensions > Frame Range works when used together with Video Sequence Editor.

1. Start a new scene. Create 2 keyframes for the default created box at position 0 and 100. Have the box make a simple movement. Now under Render menu > Dimensions > Frame Range, set the Start Frame to 50 and End Frame to 80. Render this frame range as video file. It renders correctly.

2. Create a new scene. Use the above setup but now also go to the Video Sequence Editor and do Add > Scene > Scene to add your scene stripe in channel 0.

If you now try to render the same frame range (50-80) to a video, you will see that the rendering starts from frame 100 and finishes at 130.

If I change the frame range to 20-40, then the rendering starts from frame 40 and finishes at 60.

In other words, when the Video Sequence Editor is involved, and I setup a frame range X to Y, the rendering starts from 2*X (twice as many frames after it should start).

I cannot work this out. Can you please help me?

Answer 1

In your first scene you have an animation that plays from frame 50 to 80. Frame 50 is the first frame this scene outputs.

When you use that scene in a scene strip in the VSE, this strip plays that output of the scene, the first frame that the VSE scene strip receives is frame 50 from the first scene. This first frame of the scene strip will show up where the scene strip starts, which may be frame 24 of the new scene.

This would give the same result as if you rendered the first scene to disk then added the file on disk to the VSE.

The frame range in scene two has no connection to the original scene frame range.