Maybe you have missed to install the appropriate codec. Consider reinstallation of codecs.

In order to use the DirectShow video engine, various codecs (ActiveX filters) have to be installed on your PC. Every file/format requires an ActiveX Splitter to split the streams into: Video, Audio, Subtitles etc. Then each stream requires its appropriate DirectShow ActiveX decoder. When you consider decoding various containers with DirectShow like: AVI, MKV, MOV, MP4, 3GP, FLV etc.. a large number of ActiveX filters are required to be installed on your PC. Problems often occur on PCs loaded with "codec packs" that are marketed as the best solution to decode everything! Codecs conflict is the main reason of failure when playing or decoding most multimedia formats.

To get the most reliable DirectShow configuration, these software prerequisites should be installed on your PC after you have uninstalled any "codec packs":

• Prerequisites Win XP (includes .NET Framework 2.0, WMP11 runtime, ffdshow tryouts, Haali Media Splitter and configfiles for ffdshow)
• Prerequisites Win 7 (includes ffdshow tryouts, Haali Media Splitter and configfiles for ffdshow)