Recently everything I convert plays back very...poorly. Movement (especially fast movement) isn't fluid and it looks rather poor. I haven't had this issue before ever. Could anyone help?

So I've used Winavi 6.3, 7.1, 7.6, 7.7 and all them spilt any file I try to convert to matter how big it is. I've tried almost every way to convert things and still it doesn't go in one folder! Please help