I doubt you will succeed on appeal. You apparently did have the opportunity to show a larger portion of the video for context. You apparently did not object to the shorter clip, or to the manner in which the longer version was played back. You apparently also did not object to the full-length version. You did not obtain your own version to present, and apparently did not attempt formal discovery or a subpoena to obtain a copy before trial. You apparently also didn't seek discovery, assuming it was permitted in the court where the litigation occurred, to compel that the other side turn over any copy of its exhibits before trial. You knew of the full videotape before the trial, and you knew what was on it, so you can't claim that this is newly discovered evidence.
I suspect the appellate court will view this as your wanting a "do over". It's your job to have your witnesses and evidences ready on the day of trial.
I suspect that the real problem here is that the other side had the sense to get help from a lawyer and the lawyer took full advantage of your unfamiliarity with the legal process and rules of evidence - that's perfectly legal.
Still, if you want to appeal, it appears to be the only path to recovery. Be aware, though, that appeals aren't easy, either.

