I'm trying to run .wmv video files and collect responses. But every time I run the test, the videos play inconsistently - sometimes smoothly, sometimes smoothly with audio about 500ms behind, sometimes in a very stop-start manner and sometimes as if in slow-motion with stop-start audio.

When I run them in standalone WMP 10 or 11, I get some audio sync problems, but not quite to the same extent. I've tried every possible combination of WMP video acceleration setting and tried increasing the trial interval, but it's still inconsistent. Is there something I'm missing?

M