Linux bubastis 3.10.25-gentoo #10 SMP Thu Jan 30 22:17:35 UTC 2014 x86_64 Intel(R) Core(TM) i7-4800MQ CPU @ 2.70GHz GenuineIntel GNU/Linux
NVIDIA Corporation GK107GLM [Quadro K1100M]
Short description of error
The video sequence editor's preview window does not match up with
the rendered output when a video strip refers to a blender scene
with an aspect ratio different from the aspect ratio of the
Exact steps for others to reproduce the error
Create first scene with 40x40 resolution. fill it with 3d objects
Create second scene with 1920x1080 resolution. put some text on the right side.
Create third scene with 1920x1080 resolution. This is a VSE project. Incorporate the first scene on top of the second scene.
Check the Image Offset option on the 40x40 scene
Add a transform strip to the 40x40 scene and set the scale and position parameters so it fills the left side of the composite scene with the text from the second scene visible on the right.
Notice how at each stage the rendered output is different from the view in the preview window. This discrepancy confounds new users as they attempt to construct a mental model of how blender works and delays understanding and competence.
I am pretty sure this relates to the TODO regarding a rewrite of the Video Sequence Editor, but I'm going to incorporate my narrative from the sample .blend because I don't want the issues relating to pixel_aspect_ratio to fall through the cracks when this TODO transitions to a todone.