Here's some hints and tips for reducing your 8 hours of video to some interesting short clips that can then be sent to me to include in a ride video 
1. Download "MPEG Streamclip". It's free, just google it, there's even a MAC version.
2. Open your MP4 file in it
Spacebar to start\stop playback
Cursor keys right and left to scroll forward and back
Cursor keys up and down for fast forward and rewind
3. When you find the start of something interesting (seel below), press the "I" key (for "In")
4. Play or scroll forwards until it's less interestinbg and press to "O" key (for "Out")
5. Press Ctrl+T (trims the clip to only what's between the In and Out
6. Press Ctrl+S (to save the clip)
7. Press CTRL+Z to undo the trim and return you to the place you marked with "I"
8. Fast forward to the end of the grey section of the location bar (that's where you pressed "O")
9. Play or scroll to the start of the next interesting bit and repeat from step 3
10. When you reach the end of the file, Press Ctrl+O to open the next file
Saving clips:
If you have video of several days, always start the name of the saved file with the day (Sat, Sun etc)
If the clip is of a particular incident or place, use that in the name and add a counter (e.g. "in the castle 01", "in the castle 02")
If it's just general on the road stuff I just number the clips 01, 02 etc (it's the quickest way to save the file without typing a long file name)
What to save:
Hours and hours of the back of someone's bike is boring. Look for:- Overtakes, Junctions, all the bikes passing you when you are marking a corner, arriving at a stop and leaving a stop, anything OFF the bike like lunchtime. The back of someones bike on long sweeping bends with nice scenery are also good though.