How come when I try and export my time series in ArcMap it compresses the video to 3 seconds? My time change visualization is at least 10. What can I do to make my exported video longer?
I have found exporting video either from Time or Animation to be rather buggy; I routinely get different results with the same inputs, if I get results at all. Depending on the export and codec options you choose, as well as the player used, you may also get varied results on playback time. More information about exactly what settings you are using could be helpful - particularly which version of ArcMap you're using.
However, I also recall running into the exact same problem you describe. It's been a while, but I believe the solution was on the Time Slider bar go into Options and the Playback tab. There, change from using the playback speed bar to a specified playback duration in seconds. Any exported video should run the specified length.
Alternatively, if playback works as you want it within Arc, you could investigate a screen capture/recording utility and use that to record Arc doing the playback rather than relying on an export.