Hands On: Decoding Matroska's mysteries

If you like playing high-definition video on your PC, you’ll almost certainly have come across the Matroska file format (MKV).

Matroska has become the AVI of the HD era, and is commonly used for transporting high-definition content.

If you’ve tried to play an MKV file though, you may have experienced disappointing performance with dropped frames or an inability to hear multi-channel surround sound.

Like all digital formats, Matroska has been used to distribute copyrighted material, but it can equally be used for open, officially licensed or personally owned content.

As such, it’s an important format and here we’re concerned with the requirements for playing it smoothly on your PC.

What is Matroska?
Matroska is actually a container for AV files. So like AVI, you can’t encode a file into the Matroska format, then decode it for playback. Instead you would encode a file into something like MPEG2, DivX or H.264, then transport it in Matroska.

As a container format, Matroska takes care of navigation of the actual content, along with managing multiple audio and subtitle streams. Matroska is an open format and aims to be extendable and as future-proof as possible, giving it an advantage over many existing container formats.

You’ll come across Matroska as a container for video and audio, using the file extension MKV, although there’s also an audio-only version called MKA.

Playing Matroska
To play Matroska files on a Windows PC, you’ll typically need three pieces of software: a media splitter, media decoder and a media player. The media splitter is used to access the video and audio files within the Matroska container. The most popular for Matroska playback is the free Haali Media Splitter.

The media splitter allows access to the separate video and audio files, but knows nothing about how they’re encoded, so you’ll then need the appropriate decoding software. This depends on what encoding format was used for the video files in question, but most of those commonly contained in Matroska files are covered by the free FFDShow.

You should now be able to enjoy most Matroska files in the media player of your choice, but you may still be disappointed by the result. If you’re running the latest Windows Media Player for example, you may still experience choppy playback and stereo sound when you expected smooth video and multi-channel audio.

Rather than automatically looking at upgrading your hardware, the answer could be to use a different media player. One of the most popular for Matroska is a modified version of an older Windows Media Player.

The so-called Media Player Classic is freely available and at first glance appears very basic. But it’s this simplicity, along with built-in support for modern tasks, which makes it one of the consistently reliable media players around.

We’ve wasted hours trying to get WMP 10 or 11 to work smoothly or deliver multi-channel audio, only to find Media Player Classic getting it right first time without modification. We’ve also found it integrates better with third-party utilities like the AC3 Filter, which can be used to ensure multi-channel audio is either passed-through an SPDIF connector unmodified, or encoded in real-time to Dolby Digital.

The latest Media Player Classic is a March 2006 file. AC3 Filter can be found here. You can also use alternative media players, some of which already have the required codecs built-in. VLC, the Core Media Player and Zoomplayer are popular choices.

The easy route
Recognising that Matroska playback typically involves downloading a splitter, a codec and an appropriate media player, many sources now offer a single pack with the latest versions of each, along with additional utilities and codecs to cover most eventualities. The Combined Community Codec Pack (CCCP) is a popular choice, or the K-Lite codec pack.

While single packs appear to offer the most convenient route, we’ve found they often install more items than you need, so for a minimalist approach, we’d recommend installing a separate splitter, decoder and player.

Job done
If you’ve had headaches getting modern media players working smoothly, it can be a breath of fresh air to find Media Player Classic just getting the job done without hassle or unnecessary overheads.