Editing DirectShow (section)

==Features==
By default, DirectShow includes a number of filters for decoding some common media file formats such as [[MPEG-1]], [[MP3]], [[Windows Media Audio]], [[Windows Media Video]], [[Musical Instrument Digital Interface|MIDI]], [[Container format (digital)|media containers]] such as [[Audio Video Interleave|AVI]], [[Advanced Systems Format|ASF]], [[WAV]], some splitters/demultiplexers, multiplexers, source and [[Sink (computing)|sink]] filters, some static image filters, some video acceleration, and minimal [[digital rights management]] (DRM) support.<ref name="formats">{{cite web|url=https://msdn.microsoft.com/en-us/library/ms787745(VS.85).aspx|title=Formats supported by default in DirectShow|work=MSDN Library|publisher=Microsoft|access-date=2005-09-11}}</ref><ref>{{cite web|url=http://retrakker.antville.org/stories/1548487/|title=Microsoft's next scapegoat - DirectShow!|work=retrakker|date=2007-01-13|access-date=2010-08-18}}</ref> DirectShow's standard format repertoire can be easily expanded by means of a variety of filters, enabling DirectShow to support virtually any container format and any audio or video codec. For example, filters have been developed for [[Ogg Vorbis]], [[Musepack]], and [[Dolby AC-3|AC3]], and some codecs such as [[MPEG-4|MPEG-4 Advanced Simple Profile]], [[Advanced Audio Coding|AAC]], [[H.264]], [[Vorbis]] and containers [[.mov|MOV]], [[MP4]] are available from 3rd parties like [[ffdshow]], [[K-Lite]], and [[Combined Community Codec Pack|CCCP]].<ref name="ovfilter">{{cite web|url=http://www.illiminable.com/ogg/|title=illiminable Directshow Filters for Ogg Vorbis, Speex, Theora and FLAC|access-date=2006-03-11|url-status=dead|archive-url=https://web.archive.org/web/20060224081849/http://www.illiminable.com/ogg/|archive-date=2006-02-24}}</ref><ref>{{cite web|url=http://blog.monogram.sk/janos/directshow-filters/|title=Monogram's DirectShow filters for Musepack, AAC and AMR|access-date=2008-03-08|archive-url=https://web.archive.org/web/20110926032811/http://blog.monogram.sk/janos/directshow-filters/|archive-date=2011-09-26|url-status=dead}}</ref><ref>{{cite web|url=http://ac3filter.net/|title=AC3Filter|access-date=2010-08-13}}</ref> Incorporating support for additional codecs such as these can involve paying the licensing fees to the involved codec technology developer or patent holder.{{Citation needed|date=August 2010}} Finally, there are "bridge" filters that simultaneously support multiple formats, as well as functions like stream multiplexing, by exposing the functionality of underlying multimedia APIs such as [[VLC media player|VLC]].<ref>{{cite web|url=http://www.sensoray.com/support/videoLan.htm|author1=Anderson, Dean |author2=Lamberson, Jim |title=Using VideoLan VLC in DirectShow|work=An open source bridge from VLC to DirectShow|year=2007|access-date=2008-02-15}}</ref>

The amount of work required to implement a filter graph depends on several factors. In the simplest case, DirectShow can create a filter graph automatically from a source such as a file or URL.<ref>{{cite web|url=http://www.flipcode.com/archives/DirectShow_For_Media_Playback_In_Windows-Part_III_Customizing_Graphs.shtml|title=DirectShow For Media Playback In Windows - Part III: Customizing Graphs|author=Thompson, Chris|work=FLIPCODE.COM|date=2000-09-13|access-date=2010-08-18}}</ref> If this is not possible, the developer may be able to manually create a filter graph from a source file, possibly with the addition of a custom filter, and then let DirectShow complete the filter graph by connecting the filters together. At the next level, the developer must build the filter graph from scratch by manually adding and connecting each desired filter. Finally, in cases where an essential filter is unavailable, the developer must create a custom filter before a filter graph can be built.{{Citation needed|date=August 2010}}

Unlike the main C API of QuickTime where it is necessary to call MoviesTask in a loop to load a media file, DirectShow handles all of this in a transparent way. It creates several background threads that smoothly play the requested file or URL without much work required from the programmer.{{Citation needed|date=August 2010}} Also in contrast to QuickTime, nothing special is required for loading a URL instead of a local file on disk{{snd}}DirectShow's filter graph abstracts these details from the programmer, although recent developments in QuickTime (including an [[ActiveX control]]) have reduced this disparity.{{Citation needed|date=August 2010}}