I'am not an expert in Video Codecs but it seems somehow to wait for a main frame (scene change) to wait till it continuous - and this might take some minutes. During this time the picture is still and only looks like it's hanging - but in fact it does not (the filters didn't make it better).
The "main frame" you're referring to is called a Keyframe. MPEG codecs (all versions) are temporal compression codecs. Most videos don't differ much from one frame to the next. For example, in a video when someone walks from one side of the room to the other, the person moves, but the rest of the room stays pretty much the same. Temporal compression works by using the similarities in the different frames to "save space" by not repeating the same information for all of the pixels in the video that stay the same from one frame to the next. So, instead of describing every single pixel in the video for each frame, it only says "show exactly the same thing as the last frame, but change this, this, this, and this. Every so often, the videos include keyframes, which are essentially "full frames" (they include all of the data regardless of whether it had changed from the previous frame).
When you are creating the video file, you can specify how often you want the software to include these keyframes. The more keyframes you include, the better "scrubbing" (FF and RW) support you have, but the larger the video file will be (because Keyframes aren't compressed very well at all).
You may want to take some time to educate yourself on how DirectShow works. There is an extensive guide available here:
http://wiki.jrmediacenter.com/index.php/DirectShow_Playback_Guide