Editing VC-1 (section)

==Microsoft codec implementations==
The VC-1 codec specification has so far been implemented by Microsoft in the form of three codecs, each identified with a unique [[FourCC|four character code]].<ref>{{cite web|last=Sullivan|first=Gary J.|title=DirectX Video Acceleration Specification for Windows Media Video v8, v9 and vA Decoding (Including SMPTE 421M "VC-1")|url=http://download.microsoft.com/download/5/d/c/5dc91455-0a8c-4d57-8975-0afe1cfaf0dd/DXVA_WMV.pdf|work=Microsoft Developer Network (MSDN) Library, Windows Development Kit, Windows Driver Kit, Device and Driver Technologies, Display Devices (Adapters and Monitors), Design Guide, Windows 2000 Display Driver Model Design Guide|publisher=[[Microsoft]]|access-date=29 October 2010|orig-year=December 2007|date=August 2010}}</ref>

===WMV3===
The Simple and Main Profiles of VC-1 remained completely faithful to the existing WMV3 implementation, making WMV3 bitstreams fully VC-1 compliant.
The WMV3 codec was designed to primarily support progressive encoding for computer displays. An interlaced encoding mode was implemented, but quickly became deprecated when Microsoft started implementing WMV Advanced Profile. Whereas WMV3 progressive encoding was implemented using the [[YUV 4:2:0]] color sampling scheme, the deprecated interlaced mode was implemented using the less common [[YUV 4:1:1]] sampling scheme.

The [[Windows Media Video]] 9 (WMV3) codec implements the Simple and Main modes of the VC-1 codec standard, providing high-quality video for streaming and downloading. "It provides support for a wide range of bit rates, from high-definition content at one-half to one-third the bit rate of MPEG-2, to low-bit-rate Internet video delivered over a dial-up modem. This codec also supports professional-quality downloadable video with two-pass and variable bit rate (VBR) encoding."<ref name=MSDN-WMC>{{cite web|title=About the Windows Media Codecs|url=http://msdn.microsoft.com/en-us/library/windows/desktop/gg153556(v=vs.85).aspx|work=Microsoft Developer Network|publisher=Microsoft|access-date=28 April 2014}}</ref>

A number of high definition movies and videos have been released commercially in a format dubbed [[WMV HD]]. These titles are encoded with WMV3 Main Profile @ High Level (MP@HL).

===WMVA===
WMVA was the original implementation of WMV Advanced Profile prior to the acceptance of the VC-1 draft by SMPTE. The codec was distributed with [[Windows Media Player]] 10 and Windows Media Format SDK 9.5 install packages. There are slight bitstream differences between WMVA and WVC1, so consequently WMVA is handled by a different [[DirectShow]] decoder than WVC1. Some 3rd party hardware and software decoders only decode WMVA based content. As of 2006, WMVA is considered a deprecated codec because it is not fully VC-1 compliant.

===WVC1===
WVC1, also known as Windows Media Video 9 Advanced Profile, implements a more recent and fully compliant Advanced Profile of the VC-1 codec standard. It offers support for interlaced content and is transport independent. With the previous version of the Windows Media Video 9 Series codec, users could deliver progressive content at data rates as low as one-third that of the MPEG-2 codec and still get equivalent or comparable quality to MPEG-2{{Citation needed|date=February 2010}}. The Windows Media Video 9 Advanced Profile codec also offers this same improvement in encoding efficiency with interlaced contents{{Citation needed|date=February 2010}}. A decoder for WVC1 is included in [[Windows Media Player|Windows Media Player 11]], which is bundled with Windows Vista and is available as a download for Windows XP. This implementation is supported in [[Microsoft Silverlight]].