DirectShow Playback Guide

Introduction

Native DirectShow filter support was added to MC11.1 in December 2005 and has been improved drastically with MC12. DirectShow is a multimedia API released by Microsoft which became a standard component of Windows with Windows 98. It is essentially a replacement for the earlier Video for Windows technology. In Windows Vista this technology has evolved into the Windows Media Foundation, which performs similar services. It provides developers with a unified interface across different programming languages to allow their applications to render or record media files, using a filter based framework.

1. What is DirectShow? What is a DirectShow filter?

Media Center plays many media formats in DirectShow. This includes DVD and many video and audio files. DirectShow is a Microsoft technology for playing audio/video media on Windows computer.

DirectShow uses the concept of “Filter Graph”. A filter graph is built with individual “Filters”. A filter is a software component in DirectShow that will work with other components to render a media file, each filter processes audio/video data in a specific way to facilitate the playing of the media files.

Filters have “pins” - points of connection between filters. Pins are the means by which media data is passed from one filter to another filter.

Generally speaking, there are three types of filters in terms of functionality: Source filters, transform filters, and renderer filters.

A source filter is a component that loads a media file for playback. The simplest source filter simply loads a file and passes the stream contained in the file to downstream filters for further processing, but some source filter would act as a “splitter”, by parsing the data into separate audio and video streams and then pass them down to other filters. Examples of source filters are “File Source” which reads data from a file, “TV tuner filter” which tunes to a TV channel, and “DVD navigator filter” which reads data from a DVD disk.

A transform filter is a filter that accepts media data from an upstream filter, process the data, and passes the data to a downstream filter. Therefore a transform filter must have both input and output pins (there may be more than one set of input and output pins on a given filter). An input pin connects to the output pin of an upstream filter (such as a source filter, which generally has only output pins). An output pin on a transform filter connects to an input pin of a downstream filter , such as a renderer filter, which has only input pins, or another transform filter. A decoder filter is a typical example of a transform filter.

A renderer filter is a component that renders a media stream, and is thus the last stage in DirectShow filter graph. For example an audio renderer is one that sends audio data to a sound card. A video renderer displays video to your computer screen.

2. What version of DirectX do I need?

In order to play media using DirectShow, you must have Microsoft DirectX installed. We recommend DirectX 9.0c to take advantage of features that are available only in late versions. This version is already installed on Windows XP and later operating systems, and you do not need to do anything in most cases. For earlier versions of Windows operating system, we recommend you download it from Microsoft website and install it.

3. Why do I need to get DirectShow filters?

In order to play media files in DirectShow, one must have DirectShow filters that can handle the media types to be played. DirectShow comes with some of the filters that are needed, for example video and audio renderers. DirectShow, however, does not include all filters that are needed. You must make sure you have needed filters for the file types you want to play. DirectShow filters come from a variety of sources. We do not, and can not, include all filters that are needed in Media Center‘s installation. In most cases you will need to install decoder filters from other sources. For example in order to play DVD on your computer you must have DVD capable MPEG-2 video decoder, and audio decoder(s) that are capable of decoding MPEG-2 audio and/or AC3 audio formats.

Some computers do come with certain filters installed by the computer vendor. However, the filters preinstalled may not be top-notch filters. In such case it is to your advantage to find and install better filters..

4. How do I install DirectShow filters?

It depends on the filter. Some filters come with an installation program. You just need to execute the program, and the installation wizard will guide you through the process. Most filter packs are installed this way.

Not all filters come with an installation wizard. Instead they are just one or more files with file extension .ax or .dll, often contained in an archival file (ZIP or RAR). In such a case, you can first extract the file(s) into a folder (any folder is fine, for example “C:\Program Files\DirectShow Filters\“ would be a good choice). Then register the filter using Windows program Regsvr32.exe. This program exists on every Windows computer. For example, if you downloaded a filter whose file name is NewFilter.ax, and you place the file in “C:\Program Files\DirectShow Filters\“, you can register it by clicking Start button and choose “Run…” command and enter the following line (including quotes):

regsvr32.exe "C:\Program Files\DirectShow Filters\newfilter.ax"

and click OK. A dialog box should pop up saying "DLLRegisterServer in C:\Program Files\DirectShow Filters\newfilter.ax succeeded", indicating that the filter is now registered with the system.

Some filters may come with two versions of them, a Unicode version and a non-Unicode verion. You should register the Unicode version as Media Center supports Unicode.

You can also unregister a filter, in case you decide you no longer need the filter, by using the command line parameter /U. For example to unregister the filter registered in the above example, you issue this command:

regsvr32.exe /U "C:\Program Files\DirectShow Filters\newfilter.ax"

You will also get a confirmation saying “DllUnRegisterServer in C:\Program Files\DirectShow Filters\newfilter.ax succeeded.”

5. What filters do I need and where do I get them?

The answer depends on what media format you want to play. In general you will need decoder filters and, in many cases, you will also need splitter filters. You can obtain commercial filters from various vendors. You can also get free, open source, filters. In this guide we will tell you about some free filters.

Before getting to individual media formats, it is a good idea introducing/recommending the following multi-filter pack and multi-format decoders:

CCCP - Combined Community Codec Pack

[CCCP Home Page]

This is a great multiple-filter pack that provides filters for playback of most media formats, including DVD. CCCP includes FFDShow (see below), which can be used to decode a large number of media formats, MPV video decoder which decodes DVD and other MPEG-2 video, and Haali Media Splitter that can be used for playback of many media types.

Make sure you read instructions before installing CCCP. As a general rule, you should uninstall any previously installed codec packs, as different codec packs often conflict with each other. You should also uninstall previously installed individual filters that CCCP includes, such as FFDShow, Haali Media Splitter. This way you will be sure CCCP install and configure the filters properly.

Additionally, when installing CCCP, make sure you uncheck the option to install FLV Splitter. The version of FLV splitter included with CCCP does not work well. See "FLV" below.

FFDShow

FFDShow is a Multi-Format Decoder filter with major Post Processing capabilities. It can be used to decode many video and audio formats. CCCP includes FFDShow. If you choose not to install CCCP, you should consider installing FFDShow.

It can be difficult for users to find a good version as there are too many different versions/builds out there.

A fairly stable but older version can be found here (ffdshow-20051129.exe)

People have had good experience with Celtic Druid's builds. You can find new builds here.

Even newer versions can be found at FFDShow tryouts.

Very good FFDshow primer on AVS: AVS FFDshow Config Primer

DVD

For DVD playback, you need DVD capable MPEG-2 video decoder and MPEG-2 / AC3 audio decoder. These filters may or may not already exist on your computer. Some computers come with filters for DVD; some do not. Filters may also come with installation of some third-party software. If you do not already have the needed filters, you may need to install them. Commercial decoders are available from various vendors. Free decoders are available and described below.

CCCP can be used for DVD playback (see above).

Alternatively you can try these filters:

Video decoders:

DScaler 5. This is still in alpha. Therefore expect to have some problems with it. I have had only one problem though. It is related to DVD menus. I experience menu problem only with one of several DVD movies I played.

Gabest Universal Open Source MPEG Video Decoder

Older versions of FFDShow video decoder do not work well with DVD (even though it has user interface to turn on DVD decoding capability). Newer versions maybe able to decode DVD.

Audio decoders:

FFDShow Audio decoder works well with DVD.

DScaler 5 (DScaler 5 includes both an audio decoder and a video decoder).

AC3Filter.

mp4 / m4a / m4v

In order to play these types of files in DirectShow engine, you will need not only decoder filters but also splitter filters.

Splitter:

You can use Haali Splitter, or MP4 splitter.

Decoder:

FFDShow (see above) is a good choice.

3ivx has a filter pack that includes all filters (splitter and decoders) needed for mp4 type. It is however not free.

FLV

FLV, flash video, is a format widely used for streaming. For example Google video and YouTube use this format. This format should play correctly in Media Center without user actions. However, if you do have problem playing them, you need to make sure the following filters are properly installed and configured.

FFDShow (see above).

You need to configure it so it will decode FLV video. Media Center should configure it for you automatically, but here is how you can do it manually:

Start -> All Programs -> FFDShow (or Combined Community Codec Pack) -> FFDShow Video Decoder Configuration. Choose "Codecs" from the top of the left panel. On the right panel, find FLV1 in the first column ("Format"), and change the value in the second column ("Decoder") from "disabled" to "libavcodec". Click OK.

FLV Splitter

Download and unzip it. Register it.

Note: The latest CCCP also includes a version of FLVsplitter that does not work with Google/YouTube videos. You should use the version linked here (built by Celtic Druid), which, in addition to being able to play FLV1 videos from Google/YouTube when used with FFDShow, also includes an FLV Video Decoder filter which decodes FLV4 format (FFDShow decodes FLV1).

To be completed ...