I have video files with MP4 extension (downloaded from my cellular phone) and it appears automatically associated with WMP in the computer.

It doesn't play correctly because the sound is not synchronized with the video. Why is that?

How can I correct this problem?

I already downloaded a Media Player Codec Pack, but I don't know if it needs some configuration and I don't know how to make it.


Install K-Lite Codec pack, it automatically removes faulty codecs.


Uninstall that codec package and any others that are installed (a must), then download this one and install it.


Says it is for Vista but is for XP also.


I wouldn't install any humongous codec packs, instead I always install these two things:

  1. ffdshow http://codecs.com/download/FFDShow.htm
  2. Haali Media Splitter (for Matroshka, mkv) http://haali.su/mkv/

ffdshow will replace other codecs, and if it, for some reason, does not:

  1. Download http://www.softella.com/dsfm/index.en.htm now either

    • Look through the codec list... See what codecs decode h.264 (which is mostly in MP4 nowadays), Google if need be
    • Just bump up the priority of the ffdshow codec, most of the time nothing will be wrong with that.

Do you insist on using WMP?
Sometimes WMP won't play files even if codecs are there.
Why don't you prefer something like VLC Media Player?

As an added bonus, if volume is actually out of sync for video in question, you can adjust volume offset in VLC.

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