Up till now, I have opened up to youtube videos in equal windows, side by side. adjusted each to a similar starting point, then tried to get both playing at the same time. It is very hit & miss.
I came across this alternative...
1. Download & install the free software called 'Kinovea' I think it is available for both Apple & Windows?
2. Go to Youtube & open up the videos you want to compare.
3. Copy the address line of the first video.
4. Open up a free software in another window called 'savefrom.net' Paste the saved address link & save to your Hard disc. It's quick!
6. Repeat for the second video you want to compare.
7. Open up the Kinovea software. click on View from the menu, then select 'two playback analysis screens'
8. Select 'File' then 'open video file' & select the first video you want to compare. Repeat for the second video in the second split screen.
You can now scrub each video to a starting location you want to compare, move frame by frame in each video so that you get it spot on. You can choose the speed of the playback of each video, save sequences.
What is really useful is the slo-mo ability. It allows you to see clearly who is compensating for oversteer/understeer by the angle of the steering wheel, turn in points, braking points, who's hitting the apex, who uses the full width of the track entering or exiting the corner, bad habits with hands on the wheel (I curl my thumbs in turning in, which looks really pants!)
Anyway, I'm sure many of you use other programs such as iMovie etc. But, this is really easy & quick. It is a really good analysing tool.