If you seek using the seekbar in Presenter ’09 and notice that your inserted .FLV or presenter .FLV jumps really far forward, or really far back, then the the .FLV’s that you are using likely don’t have a lot of keyframes.
What are keyframes?
Here is an explanation of keyframes from FLV Data Rate and Bandwidth... Demysitifed:
In many respects a video is much like a series of images on a timeline. The problem is each image will need to be drawn and this explains why digital video files can be rather hefty in size. To reduce the size of the video file and the "hit" on the processor, digital video employs two types of frames: keyframes and Difference or Delta frames.
A keyframe is a frame in the video containing the entire image. A Difference frame, if you could see it, contains only the differences between the frames. If you were to film one of the authors walking in front of a wall the keyframe would look like a Photoshop image and would contain the author and all of the details in the wall. A difference frame would not contain the wall because it hasn’t changed. The information in the difference frames is not lost, it is simply stored and added back into the frame when the video plays back.
Why are keyframes important for seeking?
The only way to seek in an .FLV is to seek to a keyframe; you can’t seek to frames in between keyframes. If the .FLV creation tool that you use sets keyframes at a low frequency, it can cause the seeking of videos to be jumpy. The good news is that most .FLV creation tools will default the keyframe rate to a frequent level, such as 1 per second, so you will be able to seek to each second in the video. However, other tools might only create them every several seconds, which means you won’t be able to seek to every second in the video.
To improve the seeking of your inserted videos, increase the number of keyframes in the .FLV.
Most .FLV creation tools allow you to do this. The Articulate Video Encoder ’09 defaults to a keyframe rate 1 per 2 seconds, which should allow your seek to behave very nicely.