An MP4 file (QuickTime container) can contain many different video and audio formats. Wowza Media Server and Flash only support H.264 (AVC1, MPEG4 Part 10), AAC (MP4A, AAC, AAC+, HE-AAC) and MP3 in an MP4 file. The tool GSpot can be used to inspect the details of an MP4 video on demand file to determine the video and audio codecs used to be sure they are supported by Wowza Media Server and Flash. You can download the tool from here:
http://www.headbands.com/gspot/
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