This information is indeed in the youtube website, however, I believe no a lot of people would know it - I took a year to realise this!! :(. Well here are the pointers to remember:
- Video format is best to be H.264, MPEG-2 or MPEG-4 preferred.
- The recommended aspect ratio of the video would be 4:3 or 16:9.
- Resolution: 640x360 or 480x360 (recommended).
- If it has audio format, try to haeve MP3 or ACC preferred.
- It is important to have 30 frames per second.
- The video should not beyond 10 min (2-3 min would be best).
- Maximum file size allowed is 1 GB.
More articeles on Toyang Qren's another blog.