@Hendrik, would the navigator filter not be neutral for the audio path? I've(maybe had) no problem when watching the movie without the menu feature.
I come back soon after I check again. What kind of information would be helpful?
Audio and Video is stored in the files interleaved, ie. audio and video alternating, so if you read the file, you read both audio and video equally. This is nice for playback, since you can just linearly read the file and all is well.
But it causes problems if you need different amounts of audio and video before it gets to the output. If the video processing chain buffers around 1 second of video (say 24 frames), but the audio chain has a latency of 2 seconds, where does the extra second of video go?
Thats most likely the cause for these problems, the source doesn't have anywhere to put the extra video while the audio chain is still asking for more data. To overcome this problem, there is a bit of buffering, so it can store a few frames of audio or video to compensate for differences in processing latency, which usually works fine. But there is a limit to how much it can buffer to keep the interactive parts of the menu actually properly interactive (if you buffer too much, that suffers), and you may be running against that limit.
Of course I could just make the buffer generally bigger, but as said above too large buffers cause the interactivity to suffer (especially in Menu playback) - which is why its fine outside of menu playback, since there bigger buffers are fine. But maybe I can add some checks that allow the buffers to dynamically grow if the audio is still starving for data, since broken playback is worse then a bit sluggish interactive playback.