crab I can't see the video because it's private. There are lots of different noises when you use the doppler as you can hear all of the fluid, etc whoosing around but when you find the baby it will sound like a galloping horse/train. When I first started using mine I couldn't find baby very well as I got confused by all of the other noises and could only hear baby faintly (probably because he was so small too!) but now I know what I'm looking for it takes me a couple of minutes to find him but then it sounds really clear!
How far gone are you? I'm now 15+4, I didn't hear the heartbeat really clearly until about 13 weeks, it was quite faint before.
I looked on YouTube for some videos to hear what others sounded like when I was confused about mine which was quite helpful. Are you in the FB group? I can post my video in there if you'd like to see?