How to play AC3 files, or avi with AC3 audio ?

How to play AC3 files, or avi with AC3 audio ? I have several video files with ac3 audio. How can I play them with my media player for Windows?

In order to play AC3 (Dolby Digital) files or DTS (Digital Theatre Surround) streams included in AVI/MKV/OGM files you must download and install AC3Filter: Free AC3 Decoding Filter

Run setup program, if installation was successful then in most cases filter is ready to work immediately and does not require any settings. So, you can play your ac3 encoded media files with any directshow-compatible multimedia player for windows.

Main features of AC3 decoder.
* Full AC3 standard compliance.
* S/P DIF passthrough support.
* Decode MPEG2 PES streams.
* Multichannel output support.
* LFE support.
* Dynamic Range Compression (DRC) support.
* Overflow control and automatic gain control.
* Gain levels control.
* Bitstream information (channel format, bitrate, sample rate, coupling freq and maximun freq).
* Input/output levels.
* Matrix mixer with direct control of mixing matrix.
* Stereo to multichannel mixing.
* DolbySurround/ProLogic/ProLogicII downmixing.
* Delays for each channel.
* Equalizer.

Most compatible mode of operation is stereo mode. It should work with any Windows version and any sound card.

Some drivers (Creative!) do not update settings in 'Control Panel->Sounds and Multimedia->Audio->Sound Playback->Advanced' after speaker configuration change in drivers. So it is necessary to check it.

It is possible that some audio processing filter (equalizers, enhancer, etc) may handle multichannel audio format incorrectly and cause problems with playback. For example center channel may fairly disappear or it will be impossible to change speaker configuration at playback time. To prevent this things do not install filter-packs and unregister unnecessary filters.

One of problematic filters is mmswitch filter (filter that support .avi and DVDs with several audio tracks and allow to switch between it, especially for multi-language films). If you mainly watch DVDs it is better to uninstall this filter and use MPEG2 parser wich support stream switching directly (standard MPEG2 Splitter for example). In this case you'll also get lower CPU usage. If MPEG2 parser does not support stream switching (Elecard for example) then many audio rendering chains are created, and all of them are working together when only one is really reproduced.

If mmswitch is really needed then it is several possibilities:

* All audio streams are ac3. For correct stream switching all decoders must have the same output format.
* First stream is ac3, and second is mp3 (or any other non- multichannel). Before switching to mp3 stream ac3 must be configured to 16bit stereo.
* First stream is mp3 and second is ac3. Before switching to ac3 filter must be confugured to 16bit stereo. You can change output format after switching.