Windows 7 supports a ton of video codecs by default, but I've found that some of the videos I have will play video but no audio.

Using the MediaInfo application, It looks like the culprit is the DTS-only audio on these video files:

Complete name        : C:\Users\Jeff\Videos\video1.mkv
Format               : Matroska
File size            : 7.95 GiB
Duration             : 2h 13mn
Overall bit rate     : 8 517 Kbps
Encoded date         : UTC 2010-10-09 19:46:55
Writing application  : mkvmerge v2.9.8 ('C'est le bon') built on Aug 13 2009 12:49:06
Writing library      : libebml v0.7.7 + libmatroska v0.8.1

ID                   : 2
Format               : DTS
Format/Info          : Digital Theater Systems
Codec ID             : A_DTS
Duration             : 2h 13mn
Bit rate mode        : Constant
Bit rate             : 1 510 Kbps
Channel(s)           : 6 channels
Channel positions    : Front: L C R, Side: L R, LFE
Sampling rate        : 48.0 KHz
Bit depth            : 24 bits
Stream size          : 1.41 GiB (18%)
Title                : English DTS
Language             : English

(I removed the video section as it isn't relevant)

There is no other audio stream in this file -- only the DTS. Clearly it is the culprit for my "video but no audio" problem. So I have two questions:

  1. Why can't Windows 7 play back DTS audio out of the box?
  2. How do you add DTS audio support to Windows 7 without installing a whole bunch of crazy new codecs I don't want or need?
  • Like I told you: install a codec pack or use VLC to play things! You put us Super Users to shame ;-)
    – Ivo Flipse
    Nov 16, 2010 at 7:28
  • Answers to your questions: 1. All compressed formats require codecs to decode the format. Windows can't playback DTS audio because it does not carry the codec inbox (but it does carry Dolby codecs) 2. You seem to have found an acceptable solution for this. There is no single 'best' approach because everyone has their own opinion on 3rd party codecs/packs. Aug 9, 2013 at 7:03

2 Answers 2


Installing ac3filter "full" from


seemed to work for me, and appears to be just the audio support I needed without adding a bunch of other crufty codecs to my system. -- but I'm unclear if it's the best solution.

  • were you getting no audio at all, or chopped up audio? I've been having problems with my HDMI output and certain mkv files with DTS soundtracks producing chopped up sound Dec 9, 2010 at 23:49

Ac3filter full and media player classic worked for me. In ac3filter on the 'Main' tab under "Output Format" I selected "Do not change" and checked the "use spdif" box, even though i'm using HDMI.

Now 2-channel audio stays 2-channel & HD audio (including DTS) plays in HD.

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