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Windows Media Video ('''WMV''') is a and Blu-ray Disc Blu-ray Disc BD-ROM Specification Adds Microsoft's VC-1 Advanced Video Codec Microsoft Technology Brings HD DVD to the Mainstream . HISTORY In 2003, Microsoft drafted a video codec specification based on its WMV 9 codec and submitted it to SMPTE for standardization. The standard was officially approved in March 2006 as SMPTE 421M, better known as VC-1 , thus making the WMV 9 codec an open but still proprietary standard. Since then, VC-1 has become one of the three mandatory video codecs for the BD-ROM and HD DVD-ROM specifications. CONTAINER FORMAT See Also: Advanced Systems Format A ''WMV file'' is in most circumstances .WMV typically describes ASF files that use Windows Media Video codecs. The audio codec used in conjunction with Windows Media Video is typically some version of Windows Media Audio , or in rarer cases, the deprecated Sipro ACELP.net audio codec. Microsoft recommends that ASF files containing non-Windows Media codecs use the generic .ASF file extension. Although WMV is generally packed into the ASF container format, it can also be put into the encoder. This container can optionally support Digital Rights Management using a combination of Elliptic Curve Cryptography key exchange, DES block cipher, a custom block cipher, RC4 stream cipher and the SHA-1 hashing function. CODECS Windows Media Video .]] Windows Media Video (WMV) is the most recognized codec within the WMV family. Usage of the term ''WMV'' often refers to this codec only. Its main competitors are and 1080p . The ''Simple'' and ''Main'' profile levels in WMV 9 are compliant with the same profile levels in the or RTP packet format. The codec is not compatible with previous WMV 9 codecs, however. streamingmedia.com Best Practices for Windows Media Encoding WMV is a mandatory video codec for PlaysForSure-certified online stores and devices, as well as platform. Microsoft Silverlight Developer Server Audio Video Streaming FAQ Windows Media Video Screen Windows Media Video Screen (WMV Screen) is a and Lossless encoding to enhance compression effiency. One of the uses for the codec is computer step-by-step demonstration videos. The first version of the codec was WMV 7 Screen, The second and current version, WMV 9 Screen, supports VBR encoding in addition to CBR. Windows Media Video Image Windows Media Video Image (WMV Image) is a video Slideshow codec. The codec works by applying timing, Panning and transition effects to a series of images during playback. Windows Media Video 9 Series Codecs: Windows Media Video 9 Image Version 2 The codec achieves a higher compression ratio and image quality than WMV 9 for still images as files encoded with WMV Image store static images rather than full-motion video. Since the codec relies on the decoder (player) to generate video frames in real-time, playing WMV Image files even at moderate resolutions (eg., 30 Frames Per Second at 1024 × 768 resolution) requires heavy computer processing. The latest version of the codec, WMV 9.1 Image, used by Photo Story 3, features additional transformation effects, but is not compatible with the original WMV 9 Image codec. Hardware support for WMV Image is available from Portable Media Centers, Windows Mobile -powered devices with Windows Media Player 10 Mobile. VIDEO QUALITY Microsoft claims that WMV 9 provides a compression ratio that is two times better than MPEG-4 , and three times better than MPEG-2; Windows Media Video 9 Series Codecs: Advanced Profile Microsoft also claims that WMV 9 is 15-50% better than WMV 8 in terms of compression efficiency. One test report published in January 2005, however, showed that WMV 9 had worse compression efficiency than WMV 8 Subjective quality of internet video codecs - Phase 2 evaluations using SAMVIQ . PLAYERS Software that can be play WMV files include Windows Media Player , PowerDVD , RealPlayer , MPlayer , VLC Media Player , and Media Player Classic . The Microsoft Zune media management software supports the WMV codec, but uses a Zune-specific variation of Windows Media DRM which is used by PlaysForSure. Many third-party players exist for various platforms such as Linux that use the FFmpeg implementation of the WMV codecs. On the WMV, a QuickTime component which allows Macintosh users to play WMV files in any player that uses the QuickTime framework. Important information for Windows Media Player for Mac users ENCODERS Software that exports video in WMV format include application suite. Programs that encode using the WMV Image codec include Windows Media Encoder and Photo Story . DIGITAL RIGHTS MANAGEMENT See Also: Windows Media DRM While none of the WMV codecs themselves contain any , is supported on many modern portable video devices and streaming media clients such as the Xbox 360. CRITICISM WMV has been the subject of numerous complaints from users and the press. Users dislike the digital rights management system which is sometimes attached to WMV files Microsoft Media Player shreds your rights The loss of the ability to restore licenses for WMV files in the Windows Media Player 11 was not positively received. In addition, the Microsoft Zune does not support the standard Windows Media DRM system, rendering protected WMV files unplayable. Zune won't play MS DRM infected files Digg - Microsoft's Zune WILL NOT Play Protected Windows Media VERSIONS SEE ALSO
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