which video players do not require file format conversion?

[memnoch]

I want to use a video player using html 5 and flash. Now the video player will be displayed on online exams and teachers will simply upload video files. I have basic extension validation where the teacher has to choose either \[code\].mp4, .ogg, .wav or .flv.\[/code\]. Now I want the video player to work on all major browsers and I do not want users to mess about converting formats. I want a video player which works for the above formats stright away on all browsers without any problems or conversions needed.Could somebody recommend a video player which can do this? I tried to use jwplayer but realised after uploading an .mp4 file that it would not display the video until I convert the video. I don't want teachers or students who have no knowledge or no access rights to be able to do this so that is why I want a different video player which just works straight away with ease.