Well, when we received the m2v file, we verified and checked it did played in Microsoft Windows Media player ver 8. So we accepted and paid the contractor. But after we authored the DVD to mux the m2v video with ac3 audio, PowerDVD shows no video. We found out the contractor used TMPGEnc to encode at 29.9 frame rate. But we did not specified and they used High Profile @ High Level instead of MP@ML. Saddly we have to encode with MP@ML again. What a costly lesson. Thanks for your help.