[John Coleyshaw]

Thanks Eric – but the background layer is 2D.

I’ve even tried replacing the background with a flat .png image instead of generating it in AE – and still the same.

[John Coleyshaw]

Thanks for your responses – here’s my System Info:

Intel Core 2 Quad CPU 2.33GHz
8GB RAM
64 bit Windows 7
ATI Radeon HD3800 Series

After Effects CS6 – Version 11.0.3.6 – all up to date

Rendering as an MP4 using Media Encoder on these settings:

Preset – Vimeo HD 720p 29.97fps
Field Order – progressive
Profile – High
Level 3.1
VBR 2 Pass
Target bitrate AND Max bitrate both set to 5

This issue appears to be affecting just the background layer which is a solid with a ramped gradient. I’ve tried redering it seperately as an MP4 and using that in the main comp instead and still get the same effect above.

The comp renders out mostly OK, but in the middle of the comp the background flickers to black and back again. I’ve rendered it out a few times previously with no problemms but this problem started appearing after I started moving the comp’s camera. (this is standard 3d btw, not ray traced. RAM preview is fine.

These are my memory & Multiprocessing settings: