VC-1 is the informal name of the SMPTE 421M
video codecA video codec is a device or software that enables video compression and/or decompression for digital video. The compression usually employs lossy data compression. Historically, video was stored as an analog signal on magnetic tape...
standard, which was initially developed as a
proprietaryProprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...
video format by
MicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
before it was released as a formal SMPTE standard video format on April 3, 2006. It is today a supported standard found in
Blu-ray DiscBlu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
s,
Windows MediaWindows Media is a multimedia framework for media creation and distribution for Microsoft Windows. It consists of a software development kit with several application programming interfaces and a number of prebuilt technologies, and is the replacement of NetShow technologies.The Windows Media SDK...
, Microsoft's Silverlight framework,
SlingboxThe Slingbox is a TV streaming media device made by Sling Media that encodes video into the VC-1 format for transmission over the Internet and provides an infrared blaster. The video encoding and IR blaster can both be operated remotely over the Internet...
, and the now-discontinued
HD DVDHD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...
.
Format
VC-1 is an evolution of the conventional
DCTA discrete cosine transform expresses a sequence of finitely many data points in terms of a sum of cosine functions oscillating at different frequencies. DCTs are important to numerous applications in science and engineering, from lossy compression of audio and images A discrete cosine transform...
-based video codec design also found in
H.261H.261 is a ITU-T video coding standard, ratified in November 1988. It is the first member of the H.26x family of video coding standards in the domain of the ITU-T Video Coding Experts Group , and was the first video codec that was useful in practical terms.H.261 was originally designed for...
,
H.263H.263 is a video compression standard originally designed as a low-bitrate compressed format for videoconferencing. It was developed by the ITU-T Video Coding Experts Group in a project ending in 1995/1996 as one member of the H.26x family of video coding standards in the domain of the ITU-T.H.263...
,
MPEG-1MPEG-1 is a standard for lossy compression of video and audio. It is designed to compress VHS-quality raw digital video and CD audio down to 1.5 Mbit/s without excessive quality loss, making video CDs, digital cable/satellite TV and digital audio broadcasting possible.Today, MPEG-1 has become...
,
MPEG-2MPEG-2 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 which permit storage and transmission of movies using currently available storage media and transmission...
, and
MPEG-4 Part 2MPEG-4 Part 2, MPEG-4 Visual is a video compression technology developed by MPEG. It belongs to the MPEG-4 ISO/IEC standards. It is a discrete cosine transform compression standard, similar to previous standards such as MPEG-1 and MPEG-2...
. It is widely characterized as an alternative to the latest
ITU-TThe ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
and MPEG video codec standard known as
H.264/MPEG-4 AVCH.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...
. VC-1 contains coding tools for interlaced video sequences as well as
progressiveProgressive scanning is a way of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence...
encoding. The main goal of VC-1 Advanced Profile development and standardization was to support the compression of interlaced content without first converting it to progressive, making it more attractive to broadcast and video industry professionals.
Both
HD DVDHD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...
and
Blu-ray DiscBlu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
have adopted VC-1 as a video standard, meaning their video playback devices will be capable of decoding and playing video-content compressed using VC-1.
Windows VistaWindows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...
partially supports HD DVD playback by including the VC-1 decoder and some related components needed for playback of VC-1 encoded HD DVD movies.
Microsoft has designated VC-1 as the
Xbox 360The Xbox 360 is the second video game console produced by Microsoft and the successor to the Xbox. The Xbox 360 competes with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generation of video game consoles...
video game consoleA video game console is an interactive entertainment computer or customized computer system that produces a video display signal which can be used with a display device to display a video game...
’s official video format, and game developers may use VC-1 for
full motion videoFull motion video based games are video games that rely upon pre-recorded TV-quality movie or animation rather than sprites, vectors, or 3D models to display action in the game. In the early 1990s a diverse set of games utilized this format...
included with games. By means of an October 31, 2006 update, people can now play all formats of Windows Media Video on the Xbox 360 from a disc, USB storage device, or streaming from their PC via Windows Media Connect/Windows Media Player 11. This allows anyone to play VC-1 encoded video on the console.
VC-1 is also supported in the
PlayStation 3The is the third home video game console produced by Sony Computer Entertainment and the successor to the PlayStation 2 as part of the PlayStation series. The PlayStation 3 competes with Microsoft's Xbox 360 and Nintendo's Wii as part of the seventh generation of video game consoles...
console and the
FFmpegFFmpeg is a free software project that produces libraries and programs for handling multimedia data. The most notable parts of FFmpeg are libavcodec, an audio/video codec library used by several other projects, libavformat, an audio/video container mux and demux library, and the ffmpeg command line...
project includes a
freeFree software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
VC-1 decoder.
Microsoft codec implementations
The VC-1 codec specification has so far been implemented by Microsoft in the form of 3 codecs, each identified with a unique
four character codeA FourCC is a sequence of four bytes used to uniquely identify data formats.The concept originated in the OSType scheme used in the Macintosh system software and was adopted for the Amiga/Electronic Arts Interchange File Format and derivatives...
.
WMV3
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 in the YUV 4:2:0 color space, the deprecated interlaced mode was implemented in the less common YUV 4:1:1 color space.
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. Windows Media Video 9 is already supported by a wide variety of players and devices."
A number of high definition movies and videos have been released commercially in a format dubbed
WMV HDWindows Media High Definition Video is the marketing name for high definition videos encoded using Microsoft Windows Media Video 9 codecs...
. 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 PlayerWindows Media Player is a media player and media library application developed by Microsoft that is used for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows Mobile-based devices...
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
DirectShowDirectShow , codename Quartz, is a multimedia framework and API produced by Microsoft for software developers to perform various operations with media files or streams. It is the replacement for Microsoft's earlier Video for Windows technology...
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. The Windows Media Video 9 Advanced Profile codec also offers this same improvement in encoding efficiency with interlaced contents. A decoder for WVC1 is included in
Windows Media Player 11Windows Media Player is a media player and media library application developed by Microsoft that is used for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as on Pocket PC and Windows Mobile-based devices...
, which is bundled with Windows Vista and is available as a download for Windows XP. This implementation is supported in
Microsoft SilverlightMicrosoft Silverlight is an application framework for writing and running rich Internet applications, with features and purposes similar to those of Adobe Flash. The run-time environment for Silverlight is available as a plug-in for web browsers running under Microsoft Windows and Mac OS X...
.
Profiles
|
Simple |
Main |
Advanced |
| Baseline intra frame compression |
|
|
|
| Variable-sized transform |
|
|
|
| 16-bit transform |
|
|
|
| Overlapped transform |
|
|
|
| 4 motion vector per macroblock |
|
|
|
| ¼ pixel luminance motion compensation |
|
|
|
| ¼ pixel chrominance motion compensation |
|
|
|
| Start codes |
|
|
|
| Extended motion vectors |
|
|
|
| Loop filter |
|
|
|
| Dynamic resolution change |
|
|
|
| Adaptive macroblock quantisation |
|
|
|
| B frames |
|
|
|
| Intensity compensation |
|
|
|
| Range adjustment |
|
|
|
| Field and frame coding modes |
|
|
|
| GOP In Video coding, a group of pictures, or GOP structure, specifies the order in which intra- and inter-frames are arranged. The GOP is a group of successive pictures within a coded video stream. Each coded video stream consists of successive GOPs...
Layer |
|
|
|
| Display metadata |
|
|
|
|
Simple |
Main |
Advanced |
Bit rates and resolutions
| Profile |
Level |
Maximum Bit Rate In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
|
Resolution / Framerate |
| Simple |
Low |
96 kbit/s |
176 × 144 / 15 (QCIF CIF , also known as FCIF , is a format used to standardize the horizontal and vertical resolutions in pixels of YCbCr sequences in video signals, commonly used in video teleconferencing systems. It was first proposed in the H.261 standard.CIF was designed to be easy to convert to PAL or NTSC...
) |
| Medium |
384 kbit/s |
240 × 176 / 30
352 × 288 / 15 (CIFCIF , also known as FCIF , is a format used to standardize the horizontal and vertical resolutions in pixels of YCbCr sequences in video signals, commonly used in video teleconferencing systems. It was first proposed in the H.261 standard.CIF was designed to be easy to convert to PAL or NTSC...
) |
| Main |
Low |
2 Mbit/s |
320 × 240 / 24 (QVGA) |
| Medium |
10 Mbit/s |
720 × 480 / 30 (480p)
720 × 576 / 25 (576p) |
| High |
20 Mbit/s |
1920 × 1080 / 30 (1080p) |
| Advanced |
L0 |
2 Mbit/s |
352 × 288 / 30 (CIF) |
| L1 |
10 Mbit/s |
720 × 480 / 30 (NTSC-SD)
720 × 576 / 25 (PAL-SD) |
| L2 |
20 Mbit/s |
720 × 480 / 60 (480p)
1280 × 720 / 30 (720p) |
| L3 |
45 Mbit/s |
1920 × 1080 / 24 (1080p)
1920 × 1080 / 30 (1080i)
1280 × 720 / 60 (720p) |
| L4 |
135 Mbit/s |
1920 × 1080 / 60 (1080p)
2048 × 1536 / 24 |
Other implementations
Due to its origins in Microsoft's WMV9 codec, the most popular implementations of VC-1 encoders have so far been done by Microsoft, though third-party implementations exist as well. Sonic Cinevision PSE, a professional VC-1 encoding tool used predominantly in
HD DVDHD DVD is a discontinued high-density optical disc format for storing data and high-definition video.Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format...
and Blu-ray encoding, is a commercial version of Microsoft's PEP (Parallel Encoder) encoding tool and VC-1 Analyzer tool. Microsoft owns the code development whereas
Sonic SolutionsSonic Solutions, acquired by Rovi Corporation in 2010, was a computer software company headquartered in Novato, California. In addition to having a number of offices in the U.S., the company also maintained offices in Europe and Asia.-History:...
owns the sales and distribution. Microsoft also provides a separate VC-1 Encoder SDK which allows any company or software developer to integrate VC-1 encoding into their applications.
Non-Microsoft VC-1 implementations (based entirely on the SMPTE specifications) have been done by
Tandberg TelevisionEricsson Television, formerly Tandberg Television, is a company providing MPEG-4 video on demand, and interactive television systems to telecommunications network operators and broadcasters. It was acquired by Swedish company, Ericsson in 2007, and was re-branded as Ericsson Television in 2010.The...
,
MainConceptMainConcept GmbH is a software company developing video/audio codecs and also applications and plug-ins related to video/audio encoding.-History:...
and
Enciris Technologies. The
FFmpegFFmpeg is a free software project that produces libraries and programs for handling multimedia data. The most notable parts of FFmpeg are libavcodec, an audio/video codec library used by several other projects, libavformat, an audio/video container mux and demux library, and the ffmpeg command line...
project includes a
freeFree software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
VC-1 decoder.
Encoding software
Windows Media EncoderWindows Media Encoder is a freely downloadable trial version 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 live and on-demand delivery. It is the successor...
9 Series encodes VC-1 compliant video files, including WVC1
FourCCA FourCC is a sequence of four bytes used to uniquely identify data formats.The concept originated in the OSType scheme used in the Macintosh system software and was adopted for the Amiga/Electronic Arts Interchange File Format and derivatives...
media. Windows Media Format 11 Runtime or Windows Media Player 11 must be installed on the computer to ensure full VC-1 compliance across all three profiles (Simple, Main and Advanced). If either of these are installed,
Windows Movie MakerWindows Movie Maker is a video creating/editing software application, included in Microsoft Windows Me, XP, and Vista. It contains features such as effects, transitions, titles/credits, audio track, timeline narration, and Auto Movie. New effects and transitions can be made and existing ones can be...
can also save VC-1 compliant videos, as can any other application built on the Windows Media Format SDK or Windows Media Codec DMOs. A Windows Media Encoder Studio Edition was initially announced for professional encoding but later cancelled by Microsoft.
Microsoft Expression EncoderMicrosoft Expression Encoder is a Windows-based program for encoding digital video for web-based video. Expression Encoder can be used to create video compressed VC-1 as well as H.264 for distribution via Microsoft Silverlight. Expression Encoder features a WPF-based modern graphical user...
which is part of
Expression StudioMicrosoft Expression Studio is a suite of tools for designing and building web and Windows client applications and rich digital media contents.- Overview :...
supports encoding VC-1 video to the Windows Media (
ASFIn computing:* Advanced Systems Format , a Microsoft streaming format associated with Windows Media Player....
) file format and the IIS Smooth Streaming format.
Video encoder products made by Inlet, Digital Rapids, Harmonic, Envivio, Elemental, Anystream, Telestream and Rhozet support VC-1 encoding (based on the Microsoft VC-1 Encoder SDK) for IPTV and Web streaming.
Hardware-based encoding and decoding
Because VC-1 encoding and decoding requires significant computing power, software implementation that run on a general-purpose CPU are typically slow, especially when dealing with
HDHigh-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...
video content. To reduce CPU usage or to do real-time encoding, special-purpose hardware may be employed, either for the complete encoding or decoding process, or for acceleration assistance within a CPU-controlled environment. A hardware VC-1 encoder can be an
ASICASIC may refer to:* Application-specific integrated circuit, an integrated circuit developed for a particular use, as opposed to a customised general-purpose device.* ASIC programming language, a dialect of BASIC...
or an FPGA.
Hardware-accelerated (also known as hardware-assisted) video decoding can either be done on dedicated, special-purpose hardware or on generic, multi-purpose hardware such as GPUs. The former is typically found in consumer electronics devices such as
Blu-ray DiscBlu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...
players and 3G/4G mobile phones, while the latter is typically found in PCs. Nearly all video cards manufactured since 2006 support some level of GPU-accelerated VC-1 decoding on the Windows platform via DirectX Video Acceleration APIs. The native Windows WMV9/VC-1 decoder (wmvdecod.dll) only supports DXVA profiles A, B and C, while 3rd party VC-1 decoders such as
CyberlinkCyberLink is a digital entertainment and multimedia products software corporation. CyberLink's 2008 revenue was $140 million with market capitalization of $420 million. Cyberlink's headquarters are based in Taipei, Taiwan with worldwide offices in Fremont, USA; Tokyo, Japan; and the Netherlands...
's support the full DXVA Profile D decode acceleration. There is no support for GPU-accelerated VC-1 decode on the MacOS platform.
Legal status
Although widely considered to be Microsoft’s product, there are actually fifteen companies in the VC-1
patent poolIn patent law, a patent pool is a consortium of at least two companies agreeing to cross-license patents relating to a particular technology. The creation of a patent pool can save patentees and licensees time and money, and, in case of blocking patents, it may also be the only reasonable method...
(as of August 17, 2006). As an SMPTE standard, VC-1 is open to implementation by anyone, although implementers are hypothetically required to pay licensing fees to the
MPEG LAMPEG LA, LLC, is a Denver-based firm that licenses patent pools covering essential patents requiredfor use of the MPEG-2, MPEG-4 Visual , IEEE 1394, VC-1, ATSC and AVC/H.264 standards...
, LLC licensing body or directly to its members, who claim to hold
essential patentAn essential patent is a patent which discloses and claims one or more inventions that are required to practice a given industry standard. Standardisation bodies, therefore, often require members disclose and grant licenses to patents and pending patent applications that they own and that cover a...
s on the format (since it is a non-exclusive licensing body).
See also
- Comparison of H.264 and VC-1
H.264 and VC-1 are popular video compression standards gaining use in the industry .-Overview:-Terminology:All sources for the below information are from the respective specifications listed in the overview section.-Features:-External links:* * * *...
- Video Compression
- VC-2 (Dirac)
External links