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Amazon Instant Video (formerly Amazon Video On Demand) is an Internet video on demand service, only available in the United States, offered by Amazon.com which offers television shows and films for rental and purchase. The service became available on September 7, 2006 as Amazon Unbox. On September 4, 2008, the service was rebranded as "Amazon Video on Demand." The Unbox name still refers to the locally installed player, which is now optional. On September 4, 2012, Amazon signed a deal with pay-TV channel Epix to feature movies on their streaming service, in a move to rival their competition Netflix. 
By default, AIV uses Flash Video in all web browsers with the Adobe Flash plugin installed. This feature was launched in public beta July 17, 2008 and was released September 4, 2008. Using Flash should make AIV relatively portable (compared to, e.g., Netflix Watch Instantly).
Customers may also download videos to TiVo Series 2 and Series 3 DVRs, except those made for use with DirecTV (DirecTiVo). Sony BRAVIA TVs equipped with an Internet Video Link device, and Panasonic VIERA TVs equipped with Viera Cast can also use Amazon VOD directly through the TV's menu system. As of April 3, 2012 the Sony PlayStation 3 officially supports Amazon Instant Video. Amazon Instant Video is also available on streaming players such as Roku. As of May 19th, 2012 Amazon Instant Video announced it would be available to Xbox 360 users, via Xbox Live. 
The optional Amazon Unbox player lets users download higher-quality copies of videos. The Unbox player is compatible only with Windows XP, Windows Vista, and Windows 7. Downloaded films include a full-resolution video file and can include a lower-resolution copy for portable devices. The content can be viewed using the Amazon Unbox Video Player, Windows Media Player, a Windows Media Center Extender such as an Xbox 360, a PlaysForSure portable device. Downloaded videos may be burned to a DVD for storage purposes, but the resulting DVD will not play on a DVD player.
Amazon.com describes the content as "DVD quality". The average video bitrate of an Amazon Unbox download equals 2500 kbit/s; this means that a two hour movie consumes roughly two gigabytes (2 GB) of storage space. In comparison, a typical DVD averages 5600 kbit/s, which makes a 2-hour movie about 4.7 GB. However, Amazon uses the VC-1 codec, a more modern codec than MPEG-2, which is used on DVDs. VC-1 achieves a higher quality picture at a smaller file size.
The quality for the TiVo files is advertised as being 2800 kbit/s and as being "of equal or better quality than videos recorded at the Best Quality setting on a TiVo Series2 DVR." 
Due to the large size of the files being downloaded, the service requires a broadband internet connection capable of sustaining transfer speeds of 800 kbit/s. A 2-hour movie may take 7 hours and 20 minutes to download using a 750 kbit/s DSL/cable connection or 1 hour and 50 minutes with a 3.0 Mbit/s DSL/cable connection. Amazon asserts that for customers with an internet connection of 3 Mbit/s or more, any Unbox file will start playing within 5 minutes. In November 2007, TiVo enabled "progressive download" for Unbox content so that users may watch downloaded files before the download is complete.
While the download versions utilize VC-1 in a WMV container, the format used for streaming HD (both purchased content and Amazon Prime unlimited streaming) is AVC with an average video bitrate of 2500 kbit/s. On a computer, this encode is streamed in a FLV container.
Users of the streaming video on demand service need only a web browser with the Adobe Flash plugin to stream videos.
For transfer to portable device, the service requires the installation of a client application which manages playback and the transfer of video to portable devices that bear the Microsoft PlaysForSure certification, such as the Creative Zen or a Portable Media Center.
For use with a TiVo DVR, no client application is needed. The user only needs a broadband enabled (and connected) Series2 or Series3 DVR. DirecTiVo DVRs are not supported.
For use on Xbox live the user needs broadband connected Xbox with Xbox live gold membership.
Sony BRAVIA TVs require an Internet Video Link to play Amazon VOD videos. Some models come equipped with this device; for other DMeX-capable models, a separate device must be purchased and installed.
Amazon VOD videos can also be played on Panasonic TVs with VIERA CAST, as well as on Samsung 650 series(pre 2011 models; not available on new Samsungs) and above HDTVs, as well as newer Vizio and LG TVs.
In the first version of Unbox, a background service would launch itself upon system startup to contact the Amazon server to see if there were any new videos to download. Also, the program would attempt to contact the Amazon server when uninstalled. This automatic behavior, which could not be disabled without uninstalling the Unbox application, drew negative reviews for its implicit permission to run arbitrary code as designated by Amazon.com personnel. This is also confirmed in the video player's license agreement. In an upgrade released shortly after launch, thought to be a response to these criticisms, Amazon made "launch on startup" optional, though disabling it necessarily disables the RemoteLoad feature, and makes the program impossible to run in non-administrator accounts.
Rented Unbox movies cannot be transferred to a portable device. They can only be viewed on the device to which they are downloaded.
TV Passes purchased in the middle of a television season require the purchase of all previous episodes of the current season. Further, TV Passes are restricted to a single season, and the user isn't notified when new seasons become available, so the user must find out through other means when the new season starts and then manually order it at the appropriate time.