HOME

TheInfoList



OR:

Windows Media Video (WMV) is a series of
video codec A video codec is software or hardware that compresses and decompresses digital video. In the context of video compression, '' codec'' is a portmanteau of ''encoder'' and ''decoder'', while a device that only compresses is typically called an ...
s and their corresponding video coding formats developed by
Microsoft Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washi ...
. It is part of the
Windows Media Windows Media is a discontinued multimedia framework for media creation and distribution for Microsoft Windows. It consists of a software development kit (SDK) with several application programming interfaces (API) and a number of prebuilt techn ...
framework. WMV consists of three distinct codecs: The original video compression technology known as ''WMV'', was originally designed for Internet streaming applications, as a competitor to
RealVideo RealVideo, or also spelled as Real Video, is a suite of proprietary video compression formats developed by RealNetworks – the specific format changes with the version. It was first released in 1997 and was at version 10. RealVideo is supported ...
. The other compression technologies, ''WMV Screen'' and ''WMV Image'', cater for specialized content. After standardization by the
Society of Motion Picture and Television Engineers The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and executives working in the m ...
(SMPTE), WMV version 9 was adapted for physical-delivery formats such as
HD DVD HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the ...
and
Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of sto ...
and became known as
VC-1 SMPTE 421, informally known as VC-1, is a video coding format. Most of it was initially developed as Microsoft's proprietary video format Windows Media Video 9 in 2003. With some enhancements including the development of a new Advanced Profile ...
. Microsoft also developed a
digital container format A container format (informally, sometimes called a wrapper) or metafile is a file format that allows multiple data streams to be embedded into a single file, usually along with metadata for identifying and further detailing those streams. Nota ...
called
Advanced Systems Format Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Media Foundation framework. ...
to store video encoded by Windows Media Video.


History

In 2003, Microsoft drafted a video compression specification based on its WMV 9 format and submitted it to SMPTE for standardization. The standard was officially approved in March 2006 as SMPTE 421M, better known as
VC-1 SMPTE 421, informally known as VC-1, is a video coding format. Most of it was initially developed as Microsoft's proprietary video format Windows Media Video 9 in 2003. With some enhancements including the development of a new Advanced Profile ...
, thus making the WMV 9 format an open standard. VC-1 became one of the three video formats for the
Blu-ray The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of st ...
video disc, along with H.262/MPEG-2 Part 2 and H.264/MPEG-4 AVC.


Container format

A ''WMV file'' uses the
Advanced Systems Format Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Media Foundation framework. ...
(ASF)
container format A container format (informally, sometimes called a wrapper) or metafile is a file format that allows multiple data streams to be embedded into a single file, usually along with metadata for identifying and further detailing those streams. No ...
to encapsulate the encoded multimedia content. While the ASF can encapsulate multimedia in other encodings than those the WMV file standard specifies, those ASF files should use the file extension and not the file extension. The ASF container can optionally support
digital rights management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted work ...
using a combination of
elliptic curve cryptography Elliptic-curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys compared to non-EC cryptography (based on plain Galois fields) to provid ...
key exchange,
DES Des is a masculine given name, mostly a short form (hypocorism) of Desmond. People named Des include: People * Des Buckingham, English football manager * Des Corcoran, (1928–2004), Australian politician * Des Dillon (disambiguation), sever ...
block cipher, a custom block cipher,
RC4 In cryptography, RC4 (Rivest Cipher 4, also known as ARC4 or ARCFOUR, meaning Alleged RC4, see below) is a stream cipher. While it is remarkable for its simplicity and speed in software, multiple vulnerabilities have been discovered in RC4, ren ...
stream cipher and the
SHA-1 In cryptography, SHA-1 (Secure Hash Algorithm 1) is a cryptographically broken but still widely used hash function which takes an input and produces a 160- bit (20- byte) hash value known as a message digest – typically rendered as 40 hexa ...
hashing function. Although WMV is generally packed into the ASF container format, it can also be put into the Matroska container format (with file extension ), or
AVI Avi is a given name, usually masculine, often a diminutive of Avram, Avraham, etc. It is sometimes feminine and a diminutive of the Hebrew spelling of Abigail. People with the given name include: * Avi (born 1937), Newbery award-winning Americ ...
container format (extension ). One common way to store WMV in an AVI file is to use the WMV 9 Video Compression Manager (VCM) codec implementation.


Video compression formats


Windows Media Video

Windows Media Video (WMV) is the most recognized
video compression format A video coding format (or sometimes video compression format) is a content representation format for storage or transmission of digital video content (such as in a data file or bitstream). It typically uses a standardized video compression algo ...
within the WMV family. Usage of the term ''WMV'' often refers to the Microsoft Windows Media Video format only. Its main competitors are
MPEG-4 AVC Advanced Video Coding (AVC), also referred to as H.264 or MPEG-4 Part 10, is a video compression standard based on block-oriented, motion-compensated coding. It is by far the most commonly used format for the recording, compression, and distr ...
, AVS,
RealVideo RealVideo, or also spelled as Real Video, is a suite of proprietary video compression formats developed by RealNetworks – the specific format changes with the version. It was first released in 1997 and was at version 10. RealVideo is supported ...
, and
MPEG-4 ASP MPEG-4 Part 2, MPEG-4 Visual (formally ISO/IEC 14496-2) is a video compression format developed by the Moving Picture Experts Group (MPEG). It belongs to the MPEG-4 ISO/IEC standards. It uses block-wise motion compensation and a discrete cosine ...
. The first version of the format, WMV 7, was introduced in 1999, and was built upon Microsoft's implementation of
MPEG-4 Part 2 MPEG-4 Part 2, MPEG-4 Visual (formally ISO/IEC 14496-2) is a video compression format developed by the Moving Picture Experts Group (MPEG). It belongs to the MPEG-4 ISO/IEC standards. It uses block-wise motion compensation and a discrete cosi ...
. Continued proprietary development led to newer versions of the format, but the
bit stream A bitstream (or bit stream), also known as binary sequence, is a sequence of bits. A bytestream is a sequence of bytes. Typically, each byte is an 8-bit quantity, and so the term octet stream is sometimes used interchangeably. An octet ma ...
syntax was not frozen until WMV 9. While all versions of WMV support
variable bit rate Variable bitrate (VBR) is a term used in telecommunications and computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processe ...
,
average bit rate In telecommunications, average bitrate (ABR) refers to the average amount of data transferred per unit of time, usually measured per second, commonly for digital music or video. An MP3 file, for example, that has an average bit rate of 128 k ...
, and
constant bit rate Constant bitrate (CBR) is a term used in telecommunications, relating to the quality of service. Compare with variable bitrate. When referring to codecs, constant bit rate encoding means that the rate at which a codec's output data should be ...
, WMV 9 introduced several important features including native support for
interlaced video Interlaced video (also known as interlaced scan) is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. Th ...
, non-square
pixels In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the sm ...
, and frame interpolation. WMV 9 also introduced a new profile titled ''Windows Media Video 9 Professional'',Windows Media 9 Series Beta Reviewer's Guide
which is activated automatically whenever the video resolution exceeds 300,000 pixels (e.g., 528 px × 576 px, 640 px × 480 px or 768 px × 432 px and beyond) and the bitrate 1000 kbit/s. It is targeted towards high-definition video content, at resolutions such as
720p 720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcas ...
and
1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ve ...
. The ''Simple'' and ''Main'' profile levels in WMV 9 are compliant with the same profile levels in the
VC-1 SMPTE 421, informally known as VC-1, is a video coding format. Most of it was initially developed as Microsoft's proprietary video format Windows Media Video 9 in 2003. With some enhancements including the development of a new Advanced Profile ...
specification.Using the Advanced Settings of the Windows Media Video 9 Advanced Profile Codec
The ''Advanced Profile'' in VC-1 is implemented in a new WMV format called ''Windows Media Video 9 Advanced Profile''. It improves compression efficiency for interlaced content and is made transport-independent, making it able to be encapsulated in an
MPEG transport stream MPEG transport stream (MPEG-TS, MTS) or simply transport stream (TS) is a standard digital container format for transmission and storage of audio, video, and Program and System Information Protocol (PSIP) data. It is used in broadcast syste ...
or RTP packet format. The format is not compatible with previous WMV 9 formats, however. WMV is a mandatory video format for PlaysForSure-certified online stores and devices, as well as Portable Media Center devices. The
Microsoft Zune Zune is a discontinued line of digital media products and services marketed by Microsoft from November 2006 until its discontinuation in June 2012. Zune consisted of a line of portable media players, digital media player software for Windows PC ...
,
Xbox 360 The Xbox 360 is a home video game console developed by Microsoft. As the successor to the original Xbox, it is the second console in the Xbox series. It competed with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generati ...
,
Windows Mobile Windows Mobile is a discontinued family of mobile operating systems developed by Microsoft for smartphones and personal digital assistants. Its origin dated back to Windows CE in 1996, though Windows Mobile itself first appeared in 2000 as Pock ...
-powered devices with Windows Media Player, as well as many uncertified devices, support the format. WMV HD mandates the use of WMV 9 for its certification program, at quality levels specified by Microsoft. WMV used to be the only supported video format for the
Microsoft Silverlight Microsoft Silverlight is a discontinued application framework designed for writing and running rich web applications, similar to Adobe's runtime, Adobe Flash. A plugin for Silverlight is still available for a very small number of browsers. ...
platform, but the H.264 format is now also supported starting with version 3.


Windows Media Video Screen

Windows Media Video Screen (WMV Screen) are video formats that specialise in
screencast A screencast is a digital recording of computer screen output, also known as a video screen capture or a screen recording, often containing audio narration. The term ''screencast'' compares with the related term ''screenshot''; whereas screensho ...
content. They can capture live screen content, or convert video from third-party screen-capture programs into WMV 9 Screen files. They work best when the source material is mainly static and contains a small color
palette Palette may refer to: * Cosmetic palette, an archaeological form * Palette, another name for a color scheme * Palette (painting), a wooden board used for mixing colors for a painting ** Palette knife, an implement for painting * Palette (company) ...
. One of the uses for the format is computer step-by-step demonstration videos. The first version of the format was WMV 7 Screen. The second version, WMV 9 Screen, supports VBR encoding in addition to CBR. Additionally there is MSA1 (aka “MS ATC Screen codec” or “MSS3”) which is used in
Live Meeting Live may refer to: Arts, entertainment, and media Films * ''Live!'' (2007 film), 2007 American film * ''Live'' (2014 film), a 2014 Japanese film *'' ''Live'' (Apocalyptica DVD) Music *Live (band), American alternative rock band * List of albums ...
2007. FourCCs for the formats are MSS1, MSS2 and MSA1.


Windows Media Video Image

Windows Media Video Image (WMV Image) is a video
slideshow A slide show (slideshow) is a presentation of a series of still images ( slides) on a projection screen or electronic display device, typically in a prearranged sequence. The changes may be automatic and at regular intervals or they may be manu ...
format. The format works by applying timing, panning and transition effects to a series of images during playback. 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 format relies on the decoder (player) to generate video frames in real-time, playing WMV Image files even at moderate resolutions (e.g. 30
frames per second A frame is often a structural system that supports other components of a physical construction and/or steel frame that limits the construction's extent. Frame and FRAME may also refer to: Physical objects In building construction *Framing (con ...
at 1024 px × 768 px resolution) requires heavy computer processing. The latest version of the format, WMV 9.1 Image, used by Photo Story 3, features additional transformation effects, but is not compatible with the original WMV 9 Image format. Hardware support for WMV Image is available from Portable Media Centers,
Windows Mobile Windows Mobile is a discontinued family of mobile operating systems developed by Microsoft for smartphones and personal digital assistants. Its origin dated back to Windows CE in 1996, though Windows Mobile itself first appeared in 2000 as Pock ...
-powered devices with Windows Media Player 10 Mobile. Since no known domestic DVD player supports this format, users of Photo Story 3 wishing to generate material capable of being played in a DVD player will first have to convert to
MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU) is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods, ...
before burning a DVD (average file sizes in MPEG-2 are 5 to 6 times the .wmv file).


Versions


Audio compression formats

The audio format used in conjunction with Windows Media Video is typically some version of
Windows Media Audio Windows Media Audio (WMA) is a series of audio codecs and their corresponding audio coding formats developed by Microsoft. It is a proprietary technology that forms part of the Windows Media framework. WMA consists of four distinct codecs. The ...
, or in rarer cases, the deprecated Sipro ACELP.net audio format. Microsoft recommends that ASF files containing non-Windows Media formats use the generic file extension.


Players

Software that can play WMV files includes
Windows Media Player Windows Media Player (WMP) is the first media player and media library application that was developed by Microsoft for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as ...
, RealPlayer, MPlayer, Media Player Classic, VLC Media Player and
K-Multimedia Player K-Multimedia Player (commonly known as The KMPlayer, KMPlayer or KMP) is an Adware-supported media player for Windows and iOS that can play most current audio and video formats, including VCD, HDML, DVD, AVI, MKV, Ogg, OGM, 3GP, MPEG-1/2/4, ...
. The Microsoft Zune media management software supports the WMV format, but uses a Zune-specific variation of
Windows Media DRM Windows Media DRM or WMDRM, is a Digital Rights Management service for the Windows Media platform. It is designed to provide delivery of audio or video content over an IP network to a PC or other playback device in such a way that the distributor ca ...
which is used by PlaysForSure. Many third-party players exist for various platforms such as
Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, whi ...
that use the
FFmpeg FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing of vid ...
implementation of the WMV format. On the
Macintosh The Mac (known as Macintosh until 1999) is a family of personal computers designed and marketed by Apple Inc., Apple Inc. Macs are known for their ease of use and minimalist designs, and are popular among students, creative professionals, and ...
platform, Microsoft released a
PowerPC PowerPC (with the backronym Performance Optimization With Enhanced RISC – Performance Computing, sometimes abbreviated as PPC) is a reduced instruction set computer (RISC) instruction set architecture (ISA) created by the 1991 Apple– IBM– ...
version of Windows Media Player for
Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lap ...
in 2003, but further development of the software ceased. From January 2006 to May 2014, Microsoft endorsed and distributed the 3rd party Flip4Mac, a
QuickTime QuickTime is an extensible multimedia framework developed by Apple Inc., capable of handling various formats of digital video, picture, sound, panoramic images, and interactivity. Created in 1991, the latest Mac version, QuickTime X, is a ...
Component developed by Telestream that allowed Macintosh users to play WMV files in any player that used the QuickTime framework. Telestream ended sales of Flip4Mac on 1 July 2019 and officially ended support on 28 June 2020. The Elmedia player, which can play WMV files on Macintosh computers, is still available.


Encoders

Many programs can export video in WMV format; a few examples are
Windows Movie Maker Windows Movie Maker (known as Windows Live Movie Maker for the 2009 and 2011 releases) is a discontinued video editing software program by Microsoft. It was first included in Windows Me on September 14, 2000 and in Windows XP on October 25, 2001 ...
,
Windows Media Encoder Windows Media Encoder (WME) is a discontinued, freeware media encoder developed by Microsoft which enables content developers to convert or capture both live and prerecorded audio, video, and computer screen images to Windows Media formats for ...
,
Microsoft Expression Encoder Microsoft Expression Encoder (formerly Expression Media Encoder) is a transcoding and non-linear video editing software application for Microsoft Windows. It can create video streams for distribution via Microsoft Silverlight. This utility is c ...
, Sorenson Squeeze, Sony Vegas Pro,
AVS Video Editor AVS Video Editor is a video editing software published by Online Media Technologies Ltd. It is a part of AVS4YOU software suite which includes video, audio, image editing and conversion, disc editing and burning, document conversion and registry ...
, VSDC Free Video Editor, Telestream Episode, Telestream FlipFactory, and
FFmpeg FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing of vid ...
. Programs that encode using the WMV Image format include
Windows Media Encoder Windows Media Encoder (WME) is a discontinued, freeware media encoder developed by Microsoft which enables content developers to convert or capture both live and prerecorded audio, video, and computer screen images to Windows Media formats for ...
,
AVS Video Editor AVS Video Editor is a video editing software published by Online Media Technologies Ltd. It is a part of AVS4YOU software suite which includes video, audio, image editing and conversion, disc editing and burning, document conversion and registry ...
, and Photo Story.


Digital rights management

While none of the WMV formats themselves contain any
digital rights management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted work ...
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. Windows Media DRM, a component of PlaysForSure and
Windows Media Connect Windows Media Connect (WMC) is a UPnP AV server from Microsoft for Windows XP and later Windows operating systems, to share and stream media on a Windows computer to WMC clients. The first two releases of WMC were made available as stand-alone sof ...
, 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. In 2007, the loss of the ability to restore licenses for WMV files in the Windows Media Player 11 was not positively received.


See also

* JPEG XR/HDHD, an image file format and format developed by Microsoft


References


External links


Description of the algorithm used for Windows Media encryptionDemonstration of WMV 9 delivering 720p video at 1.8 mbit/s ABRDemonstration of WMV 9 delivering 1080p video at 10 mbit/s ABRHistory of Windows Media Player
(archived 2009) {{Compression Software Implementations Video codecs Microsoft proprietary codecs Microsoft Windows multimedia technology Digital rights management systems