YouTube

YouTube, LLC You
Tube Logo.svg
Type Subsidiary of Google, limited liability company
Founded February 14, 2005
Founder(s) Steve Chen, Chad Hurley, Jawed Karim
Headquarters 901 Cherry Ave, San Bruno,
California, United States
Area served Worldwide
Key people Salar Kamangar (CEO)
Chad Hurley (Advisor)
Industry Internet
Parent Independent (2005–2006)
Google (2006–present)
Slogan Broadcast Yourself
Website YouTube.com
(see list of localized domain names)
Alexa rank steady 3 (February 2012)
Type of site Video hosting service
Advertising Google AdSense
Registration Optional (Only required for certain tasks such as viewing flagged videos, viewing flagged comments and uploading videos)
Available in 54 language versions available through user interface
Launched February 14, 2005
Current status Active
[show]Screenshot

YouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos.

The company is based in San Bruno, California, and uses Adobe Flash Video and HTML5 technology to display a wide variety of user-generated video content, including movie clips, TV clips, and music videos, as well as amateur content such as video blogging and short original videos. Most of the content on YouTube has been uploaded by individuals, although media corporations including CBS, the BBC, VEVO, Hulu, and other organizations offer some of their material via the site, as part of the YouTube partnership program.

Unregistered users can watch videos, while registered users can upload an unlimited number of videos. Videos considered to contain offensive content are available only to registered users at least 18 years old.

In November 2006, YouTube, LLC was bought by Google for US$1.65 billion, and now operates as a subsidiary of Google.

· Features

Viewing YouTube videos on a personal computer requires the Adobe Flash Player plug-in to be installed on the browser. The Adobe Flash Player plug-in is one of the most common pieces of software installed on personal computers and accounts for almost 75% of online video material.

In January 2010, YouTube launched an experimental version of the site that uses the built-in multimedia capabilities of web browsers supporting the HTML5 standard. This allows videos to be viewed without requiring Adobe Flash Player or any other plug-in to be installed. The YouTube site has a page that allows supported browsers to opt in to the HTML5 trial. Only browsers that support HTML5 Video using the H.264 or WebM formats can play the videos, and not all videos on the site are available.

· Uploading

All YouTube users can upload videos up to 15 minutes in duration. Users who have a good track record of complying with the site's Community Guidelines may be offered the ability to upload videos of unlimited length, which requires verifying the account, normally through a mobile phone. When YouTube was launched in 2005, it was possible to upload long videos, but a ten-minute limit was introduced in March 2006 after YouTube found that the majority of videos exceeding this length were unauthorized uploads of television shows and films. The 10-minute limit was increased to 15 minutes in July 2010.[50] File size is limited to 2 GB for uploads from YouTube web page, and to 20 GB if up to date browser versions are used.

YouTube accepts videos uploaded in most container formats, including .AVI, .MKV, .MOV, .MP4, DivX, .FLV, and .ogg and .ogv. These include video formats such as MPEG-4, MPEG, VOB, and .WMV. It also supports 3GP, allowing videos to be uploaded from mobile phones. Videos with progressive scanning or interlaced scanning can be uploaded, but for the best video quality, YouTube prefers interlaced videos to be deinterlaced prior to uploading. All the video formats on YouTube use progressive scanning.

· Quality and codecs

YouTube originally offered videos at only one quality level, displayed at a resolution of 320x240 pixels using the Sorenson Spark codec (a variant of H.263), with mono MP3 audio. In June 2007, YouTube added an option to watch videos in 3GP format on mobile phones.In March 2008, a high quality mode was added, which increased the resolution to 480x360 pixelsIn November 2008, 720p HD support was added. At the time of the 720p launch, the YouTube player was changed from a 4:3 aspect ratio to a widescreen 16:9.With this new feature, YouTube began a switchover to H.264/MPEG-4 AVC as its default video compression format. In November 2009, 1080p HD support was added. In July 2010, YouTube announced that it had launched a range of videos in 4K format, which allows a resolution of up to 4096x3072 pixels.

YouTube videos are available in a range of quality levels. The former names of standard quality (SQ), high quality (HQ) and high definition (HD) have been replaced by numerical values representing the vertical resolution of the video. The default video stream is encoded in H.264/MPEG-4 AVC format, with stereo AAC audio.