I have created a 1280 x 720 edit in Final Cut Pro exporting as Pro Res then re-compressing it in Media Encoder to a 1280 x 720 .mp4 (H.264) which comes out at 150Mb (The youtube HD setting), but when I upload to youtube the playback lags. The edit is really quick throughout and youtube is struggling to playback, I am trying the youtube SD setting to see if that makes a difference, but does anyone have any suggestions? Settings I could try or any advice that could help.
First, you need to look to your computer as the possible culprit, as fast, new Macs with the latest Nvidia and ATI graphics cards don't have the problem playing HD content on Youtube that you're describing. If you do have a newer machine, then the problem may be your Internet connection.
Thanks David, the mac I am using is pretty fast 3.2Ghz Quad core intel (8Gb memory) and plays the pro-res quicktime .mov and the re-compressed .mp4 fine, it could be something to do with the internet connection, or maybe Flash?