Learn more about using Wikipedia for research.
if (wgNotice != '') document.writeln(wgNotice);
/*
Styles for Notices
*/
.notice-wrapper-wikimania-reg, .notice-collapsed-wrapper-wikimania-reg {
margin: 2px auto 0;
width: 100%;
padding: 0;
font-family: 'Arial','Helvetica','Tahoma',sans-serif;
color: #333;
background-color: #ddd;
font-size: .9em;
font-weight: 200;
}
.notice-wrapper-wikimania-reg
{
border: 1px solid #bbb;
background-color: #fcfcfc;
text-align: left;
font-size: .9em;
}
.notice-wrapper-wikimania-reg a
{
color: #006699;
}
.trans-box
{
text-align: right;
padding: 0;
white-space: nowrap;
}
.toggle-box-wikimania-reg
{
text-align: right;
padding: 0;
white-space: nowrap;
}
.notice-text-wikimania-reg
{
margin: 0 auto;
padding: 0 5px 3px 5px;
font-size: 1.1em;
}
.notice-links-wikimania-reg
{
text-align:right;
padding-right:4px;
font-size: .9em;
}
.line-ht-fix
{
line-height: 1em;
}
#centralNotice.collapsed .siteNoticeUser
{
display:none;
}
Registration for Wikimania 2009 is now open. Learn more.
[Hide] [Help us with translations!]
Windows Media Video
From Wikipedia, the free encyclopedia
(Redirected from Wmv)
Jump to: navigation, search
Windows Media Video
Filename extension
.wmv
Internet media type
video/x-ms-wmv
Uniform Type Identifier
com.microsoft.windows-?media-wmv
Developed by
Microsoft
Type of format
video file format
Windows Media Video (WMV) is a compressed video file format for several proprietary codecs developed by Microsoft. The original codec, known as WMV, was originally designed for Internet streaming applications, as a competitor to RealVideo. The other codecs, such as WMV Screen and WMV Image, cater for specialized content. Through standardization from the Society of Motion Picture and Television Engineers (SMPTE),[1][2] WMV has gained adoption for physical-delivery formats such as HD DVD and Blu-ray Disc.[3][4]
Contents[hide]
1 History
2 Container format
3 Codecs
3.1 Windows Media Video
3.2 Windows Media Video Screen
3.3 Windows Media Video Image
4 Video quality
5 Players
6 Decoders / Transcoders
7 Encoders
8 Digital rights management
9 Criticism
10 Versions
11 See also
12 References
13 External links
//
[edit] History
This article may be confusing or unclear to readers. Please help clarify the article; suggestions may be found on the talk page. (February 2009)
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 specifications.[3][4]
[edit] Container format
Main article: Advanced Systems Format
A WMV file is in most circumstances encapsulated in the Advanced Systems Format (ASF) container format.[5] The file extension .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.
The ASF 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.
Although WMV is generally packed into the ASF container format, it can also be put into the AVI or Matroska container format. The resulting files claim the .AVI, or .MKV file extensions, respectively. WMV can be stored in an AVI file when using the WMV 9 Video Compression Manager (VCM) codec implementation.[6][7] Another common way to store WMV in an AVI file is to use the VirtualDub encoder.
[edit] Codecs
[edit] Windows Media Video
Diagram illustrating the relative frame sizes of several common video resolutions targeted by Windows Media Video 9 Professional, starting with 480p.
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 MPEG-4 AVC, AVS, RealVideo, DivX, and Xvid. The first version of the codec, WMV 7, was introduced in 1999, and was built upon Microsoft's implementation of MPEG-4 Part 2.[8] Continued proprietary development led to newer versions of the codec, but the bit stream syntax was not frozen until WMV 9.[9] While all versions of WMV support variable bit rate, average bit rate, and constant bit rate, WMV 9 introduced several important features including native support for interlaced video, non-square pixels, and frame interpolation.[10] WMV 9 also introduced a new profile titled Windows Media Video 9 Professional,[11] which is activated automatically whenever the video resolution exceeds 300,000 pixels (e.g, 528x576, 640×480 or 768x432 and beyond) and the bitrate 1000 kbit/s[citation needed]. It is targeted towards high-definition video content, at resolutions such as 720p and 1080p.
The Simple and Main profile levels in WMV 9 are compliant with the same profile levels in the VC-1 specification.[12] The Advanced Profile in VC-1 is implemented in a new WMV codec called Windows Media Video 9 Advanced Profile. It improves compressions efficiency for interlaced content and is made transport-independent, making it able to be encapsulated in an MPEG transport stream or RTP packet format. The codec is not compatible with previous WMV 9 codecs, however.[13]
WMV is a mandatory video codec for PlaysForSure-certified online stores and devices, as well as Portable Media Center devices. The Microsoft Zune, Xbox 360, Windows Mobile-powered devices with Windows Media Player, as well as many uncertified devices, support the codec.[14] WMV HD mandates the use of WMV 9 for its certification program, at quality levels specified by Microsoft.[15] WMV is also the only supported video codec for the Microsoft Silverlight platform.[16]
[edit] Windows Media Video Screen
Windows Media Video Screen (WMV Screen) is a screencast codec. It can capture live screen content, or convert video from third-party screen-capture programs into WMV 9 Screen files. It works best when the source material is mainly static and contains a small color palette.[17] Depending on the complexity of the source material, the codec may switch between lossy and lossless encoding to enhance compression efficiency.[17]
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.[17]
[edit] 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.[18] 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.[18]
Hardware support for WMV Image is available from Portable Media Centers, Windows Mobile-powered devices with Windows Media Player 10 Mobile.[14]
[edit] 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;[19] Microsoft also claims that WMV 9 is 15–50% better than WMV 8 in terms of compression efficiency.[19] One test report published in January 2005, however, showed that WMV 9 had worse compression efficiency than WMV 8.[20] Many 3rd party WMV compilers have had worse performance than Windows Movie Maker.
[edit] Players
Screenshot of Windows Media Player 11, built into the Windows Vista operating system and available for Windows XP (all versions) as a free download which supports all Windows Media Video codecs.
Software that can play WMV files include Windows Media Player, GOM Player, ALLPlayer, The KMPlayer, PowerDVD, RealPlayer, MPlayer, VLC Media Player, Zoom 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 Macintosh platform, Microsoft released a PowerPC version of Windows Media Player for Mac OS X in 2003,[21] but further development of the software has ceased. Microsoft currently endorses the 3rd party Flip4Mac WMV, a QuickTime Component which allows Macintosh users to play WMV files in any player that uses the QuickTime framework.[22] According to the Flip4Mac website, WMV files with DRM encryption are not compatible with the component.
[edit] Decoders / Transcoders
Linux users can rely on FFmpeg based software like mplayer, mencoder.
For Mac users who wish to convert WMV to MP4, iSquint is a freeware that will do the job.
[edit] Encoders
Software that exports video in WMV format include Avid (PC Version), Windows Movie Maker, Windows Media Encoder, Microsoft Expression Encoder, Sorenson Squeeze,[23] Sony Vegas Pro,[24], Adobe Premiere Pro, Telestream Episode, and Telestream FlipFactory.[23]
Programs that encode using the WMV Image codec include Windows Media Encoder and Photo Story.
[edit] Digital rights management
Main article: Windows Media DRM
While none of the WMV codecs themselves contain any digital rights management facilities, the ASF container format, in which a WMV stream may be encapsulated, can. Windows Media DRM, which can be used in conjunction with WMV, supports time-limited subscription video services such as those offered by CinemaNow.[25] Windows Media DRM, a component of PlaysForSure and Windows Media Connect, is supported on many modern portable video devices and streaming media clients such as the Xbox 360.
[edit] 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.[26] The loss of the ability to restore licenses for WMV files in the Windows Media Player 11 was not positively received.[26] In addition, the Microsoft Zune does not support the standard Windows Media DRM system, rendering protected WMV files unplayable.[27]
[edit] Versions
Public Name
FourCC
Description
Microsoft MPEG-4 Video Codec V1
MPG4
Video for Windows-based codec. Non-standard MPEG-4 codec incompatible with the later standardized version of MPEG-4.
Microsoft MPEG-4 Video Codec V2
MP42
Video for Windows-based codec. Non-standard MPEG-4 codec incompatible with the later standardized version of MPEG-4.
Microsoft MPEG-4 Video Codec V3
MP43
Video for Windows-based codec. Non-standard MPEG-4 codec incompatible with the later standardized version of MPEG-4. This version however can only encode to ASF files, it cannot be used to encode AVI files without hacking.
Microsoft ISO MPEG-4 Video Codec V1
MP4S
DirectX Media Objects (DMO)-based codec. MPEG-4 Simple Profile compliant.
Microsoft ISO MPEG-4 Video Codec V1.1
M4S2
Windows Media Video V7
WMV1
DMO-based codec.
Windows Media Screen V7
MSS1
DMO-based codec. Optimized for low-bitrate sequential screen captures or screencasts. Deprecated in favor of Windows Media 9 Screen codec.
Windows Media Video V8
WMV2
DMO-based codec.
Windows Media Video 9
WMV3
DMO-based codec. Video for Windows (VfW/VCM) version also available.
Windows Media Video 9 Screen
MSS2
DMO-based codec. Optimized for low-bitrate sequential screen captures or screencasts.
Windows Media Video 9.1 Image
WMVP
DMO-based codec. Optimized for encoding video from sequential bitmap images. Used, for instance, by Photo Story.
Windows Media Video 9.1 Image V2
WVP2
DMO-based codec. Optimized for encoding video from sequential bitmap images. Used, for instance, by Photo Story.
Windows Media Video 9 Advanced Profile
WMVA
DMO-based codec. Video for Windows (VfW/VCM) version also available. Deprecated as VC-1 non-compliant.
Windows Media Video 9 Advanced Profile
WVC1
DMO-based codec. VC-1 compliant format.
[edit] See also
Codec – The technical term for compressor and decompressor
VC-1 – The SMPTE codec standard based on WMV 9 that supports additional broadcast industry requirements
WMV HD – The marketing name for high definition videos encoded using WMV 9 codecs
Windows Media DRM – A digital rights management component of Windows Media that controls how content can be used
Windows Media Audio – An audio file format and codec developed by Microsoft
JPEG XR / HD Photo – An image file format and codec developed by Microsoft
Windows Movie Maker – A video editing tool included with the Microsoft Windows operating system
MPlayer – A third-party, open source, cross-platform media player capable of playing many WMV files using FFmpeg
FFmpeg – A third-party cross-platform free software codec library which implements WMV and VC-1 among other formats
WMV Player – A third-party, commercial codec which allows viewing of WMV files in QuickTime for Mac OS X
Flip4Mac – QuickTime component to play and encode Windows Media files in QuickTime
Lossy data compression – Data compression with loss of information
Lossless data compression – Data compression without loss of information
Comparison of video codecs
[edit] References
^ SMPTE VC-1 Receiving Industrywide Support
^ Microsoft VC-1 Codec Now a Standard
^ a b Blu-ray Disc BD-ROM Specification Adds Microsoft's VC-1 Advanced Video Codec
^ a b Microsoft Technology Brings HD DVD to the Mainstream
^ MSDN: The Difference Between ASF and WMV/WMA Files
^ Microsoft Corporation (2003-07-07) Windows Media Video 9 VCM, Retrieved on 2009-08-07
^ Windows Media Video 9 Series Codecs: Windows Media Video 9 VCM
^ MPEG-4 makes the scene
^ Windows Media Audio & Video 9 Series
^ Microsoft Windows Media - Demos Video Quality
^ Windows Media 9 Series Beta Reviewer's Guide
^ Using the Advanced Settings of the Windows Media Video 9 Advanced Profile Codec
^ streamingmedia.com Best Practices for Windows Media Encoding
^ a b Windows Media Player Mobile FAQ
^ WMV HD DVD Encoding Profile Guidelines
^ Microsoft Silverlight Developer Server Audio Video Streaming FAQ
^ a b c Windows Media Video 9 Series Codecs: Windows Media Video 9 Screen
^ a b Windows Media Video 9 Series Codecs: Windows Media Video 9 Image Version 2
^ a b Windows Media Video 9 Series Codecs: Advanced Profile
^ Subjective quality of internet video codecs - Phase 2 evaluations using SAMVIQ
^ Windows Media Player 9 for Mac OS X
^ Important information for Windows Media Player for Mac users
^ a b Sorenson Media
^ Sony Creative Software - Vegas Pro 8 - Technical Specifications
^ PlaysForSure: CinemaNow
^ a b Microsoft Media Player shreds your rights
^ Zune won't play MS DRM infected files
[edit] External links
Windows Media Homepage at Microsoft
Description of the algorithm used for Windows Media encryption
WMV HD Content Showcase
Demonstration of WMV 9 delivering 720p video at 1.8 mbit/s ABR
Demonstration of WMV 9 delivering 1080p video at 10 mbit/s ABR
History of Windows Media Player
[show]
v • d • eMultimedia compression formats
Video compression
ISO/IEC
MJPEG · Motion JPEG 2000 · MPEG-1 · MPEG-2 (Part 2) · MPEG-4 (Part 2/ASP · Part 10/AVC) · HVC
ITU-T
H.120 · H.261 · H.262 · H.263 · H.264 · H.265
Others
AMV · AVS · Bink · CineForm · Dirac · DV · Indeo · Pixlet · RealVideo · RTVideo · SheerVideo · Smacker · Sorenson Video · Theora · VC-1 · VP6 · VP7 · VP8 · WMV · XVD
Audio compression
ISO/IEC
MPEG-1 Layer III (MP3) · MPEG-1 Layer II · MPEG-1 Layer I · AAC · HE-AAC
ITU-T
G.711 · G.718 · G.719 · G.722 · G.722.1 · G.722.2 · G.723 · G.723.1 · G.726 · G.728 · G.729 · G.729.1
Others
AC3 · AMR · AMR-WB · AMR-WB+ · Apple Lossless · ATRAC · DRA · FLAC · GSM-FR · GSM-EFR · iLBC · Monkey's Audio · μ-law · Musepack · Nellymoser · OptimFROG · RealAudio · RTAudio · SHN · Siren · Speex · Vorbis · WavPack · WMA · TAK · True Audio
Image compression
ISO/IEC/ITU-T
JPEG · JPEG 2000 · JPEG XR · lossless JPEG · JBIG · JBIG2 · PNG · WBMP
Others
APNG · BMP · EXR · GIF · ICER · ILBM · MNG · PCX · PGF · TGA · TIFF · JPEG XR / HD Photo
Media containers
General
3GP · ASF · AVI · Bink · BXF · DMF · DPX · EVO · FLV · GXF · M2TS · Matroska · MPEG-PS · MPEG-TS · MP4 · MXF · Ogg · Ogg Media · QuickTime · RealMedia · RIFF · Smacker · VOB · VVF
Audio only
AIFF · AU · WAV
See Compression Methods for methods and Compression Software Implementations for codecs
[show]
v • d • eData compression software implementations
Video compression(Comparison)
MPEG-4 ASP
3ivx · DivX · Nero Digital · FFmpeg MPEG-4 · HDX4 · Xvid
H.264/MPEG-4 AVC
CoreAVC · Blu-code · DivX H.264 · Nero Digital AVC · QuickTime H.264 · x264
Lossless
CorePNG · FFV1 · Huffyuv · Lagarith · MSU Lossless · SheerVideo
Others
CineForm · Cinepak · DNxHD · Helix DNA Producer · Indeo · libavcodec · Schrödinger (Dirac) · SBC · Sorenson · VP7 · libtheora · Windows Media Encoder
Audio compression(Comparison)
Lossy
Freeware Advanced Audio Coding (FAAC) · Helix DNA Producer · l3enc · LAME · TooLAME · libavcodec · Musepack · libvorbis · Windows Media Encoder
Lossless
FLAC · ALAC · Monkey's Audio · OptimFROG · TTA · WavPack
Archivers(Comparison)
Free software
7-Zip · Ark · bzip2 · compress · File Roller · gzip · Info-ZIP · KGB Archiver · lzop · PAQ · PeaZip · The Unarchiver · tar · Xarchiver
Freeware
7zX · DGCA · Filzip · IZArc · LHA · StuffIt Expander · TUGZip · UHarc/WinUHA · Zipeg · ZipGenius
Proprietary
ARC · ALZip · Archive Utility · ARJ · JAR · MacBinary · PKZIP/SecureZIP · PowerArchiver · Squeez · StuffIt · WinAce · WinRAR · WinZip
Command line
ARC · ARJ · JAR · Info-ZIP · LHA · lzop · PAQ · PKZIP · RAR · UPX · UHarc · tar
See Compression Methods for methods and Compression Formats and Standards for formats
Retrieved from "http://en.wikipedia.org/wiki/Windows_Media_Video"
Categories: Computer file formats Video codecs Microsoft Windows multimedia technology Digital rights management
Hidden categories: Wikipedia articles needing clarification from February 2009 All articles with unsourced statements Articles with unsourced statements from July 2009
Views
Article
Discussion
Edit this page
History
Personal tools
Try Beta
Log in / create account
if (window.isMSIE55) fixalpha();
Navigation
Main page
Contents
Featured content
Current events
Random article
Search
Interaction
About Wikipedia
Community portal
Recent changes
Contact Wikipedia
Donate to Wikipedia
Help
Toolbox
What links here
Related changes
Upload file
Special pages
Printable version
Permanent link
Cite this page
Languages
Česky
Dansk
Deutsch
Eesti
Español
Français
한국어
Hrvatski
Bahasa Indonesia
Italiano
Kapampangan
Nederlands
日本語
Polski
Português
Русский
Slovenčina
Српски / Srpski
Svenska
Türkçe
Українська
中文
This page was last modified on 7 August 2009 at 12:26.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of Use for details.Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policy
About Wikipedia
Disclaimers
if (window.runOnloadHook) runOnloadHook();
Wednesday, August 19, 2009
Subscribe to:
Post Comments (Atom)
adobe-premiere pro cc crack
ReplyDeletewas created by Adobe Inc. as part of the Adobe Creative Cloud licence scheme and published in the time-line. Adobe Premiere Pro was first introduced in 2003 and succeeds Adobe Premiere.