Features Youtube

Viewing YouTube videos on a personal computer requires the Adobe Flash Playerplug-in to be installed in 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.[35]

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.[36][37] 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.[38][39]

Uploading

Videos uploaded to YouTube by standard account holders are limited to 15 minutes in duration. When YouTube was launched in 2005, it was possible to upload longer 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.[40][41] The 10-minute limit was increased to 15 minutes in July 2010.[42] Partner accounts are permitted to upload longer videos, subject to acceptance by YouTube.[43] File size is limited to 2GB for uploads from YouTube web page, and to 20GB if Java-based Advanced Uploader is used. In December 2010, YouTube announced that holders of standard accounts would be allowed to upload videos of unlimited length, provided that they have a good history of following the site's Community Guidelines and policy on copyright.[44][45] 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.[46] 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.[47]

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),[48][49] with monoMP3 audio.[50] In June 2007, YouTube added an option to watch videos in 3GP format on mobile phones.[51] In March 2008, a high quality mode was added, which increased the resolution to 480x360 pixels[52] In November 2008 720pHD support was added so the YouTube player was changed from a 4:3aspect ratio to a widescreen16:9. .[53] 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.[54][55]

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.[56]

Comparison of YouTube media encoding options fmt value[1] 5 34 35 18 22 37 38 43 45 17 Default container FLV MP4 WebM[57] 3GP VideoEncoding Sorenson H.263 MPEG-4 AVC (H.264) VP8 MPEG-4 Visual Maxwidth(pixels) 400 640 854 480 1280 1920 4096 854 1280 176 Maxheight(pixels) 240 360 480 360 720 1080 3072 480 720 144 Bitrate[2] (Mbit/s) 0.25 0.5 0.8-1 0.5 2 3.5-5 AudioEncoding MP3 AAC Vorbis AAC Channels 12 2(stereo) Samplingrate(Hz) 22050 44100 Bitrate[2] (kbit/s) 96 128

^ 1 fmt was an undocumented URL parameter that allowed selecting YouTube quality mode without using player user interface. Since December 2010 this parameter is no longer supported.^ 2 Approximate values based on statistical data; actual bitrate can be higher or lower due to variable encoding rate.[58][59][60][61]

3D videos

In a video posted on July 21, 2009,[62] YouTube software engineer Peter Bradshaw announced that YouTube users can now upload 3D videos. The videos can be viewed in several different ways, including the common anaglyph (cyan/red lens) method which utilizes glasses worn by the viewer to achieve the 3D effect.[63][64][65].

One of the key features of YouTube is the ability of users to view its videos on web pages outside the site. Each YouTube video is accompanied by a piece of HTML, which can be used to embed it on a page outside the YouTube website. This functionality is often used to embed YouTube videos in social networking pages and blogs.[66] Embedding, as well as ranking and commenting, can be disabled by the video owner.

YouTube does not usually offer a download link for its videos, and intends for them to be viewed through its website interface.[67] A small number of videos, such as the weekly addresses by President Barack Obama, can be downloaded as MP4 files.[68] Numerous third-party web sites, applications and browser plug-ins allow users to download YouTube videos.[69] In February 2009, YouTube announced a test service, allowing some partners to offer video downloads for free or for a fee paid through Google Checkout.[70]

Platforms

Some smartphones are capable of accessing YouTube videos, dependent on the provider and the data plan. YouTube Mobile was launched in June 2007, and uses RTSP streaming for the video.[71] Not all of YouTube's videos are available on the mobile version of the site.[72]

Since June 2007, YouTube's videos have been available for viewing on a range of Apple products. This required YouTube's content to be transcoded into Apple's preferred video standard, H.264, a process that took several months. YouTube videos can be viewed on devices including Apple TV, iPod Touch and the iPhone.[73] A TiVo service update in July 2008 allowed the system to search and play YouTube videos.[74] In January 2009, YouTube launched "YouTube for TV", a version of the website tailored for set-top boxes and other TV-based media devices with web browsers, initially allowing its videos to be viewed on the PlayStation 3 and Wiivideo game consoles.[75][76] In June 2009, YouTube XL was introduced, which has a simplified interface designed for viewing on a standard television screen.[77]

On June 19, 2007, Google CEOEric Schmidt was in Paris to launch the new localization system.[78] The interface of the website is available with localized versions in 31 countries and a worldwide version.[79][80]

Country Language Launch dateBrazilPortuguese (Brazil)02007-06-19June 19, 2007[78]France French 02007-06-19June 19, 2007[78]IrelandEnglish (Ireland)02007-06-19June 19, 2007[78]Italy Italian 02007-06-19June 19, 2007[78]Japan Japanese 02007-06-19June 19, 2007[78]NetherlandsDutch02007-06-19June 19, 2007[78]Poland Polish 02007-06-19June 19, 2007[78]Spain Spanish and Catalan02007-06-19June 19, 2007[78]United KingdomEnglish (United Kingdom)02007-06-19June 19, 2007[78]MexicoSpanish (Mexico)02007-10-11October 11, 2007[81]Hong Kong English and Chinese (Traditional)02007-10-17October 17, 2007[82]Republic of China (Taiwan) Chinese (Traditional)02007-10-18October 18, 2007[82]AustraliaEnglish (Australia)02007-10-22October 22, 2007[83]New ZealandEnglish (New Zealand)02007-10-22October 22, 2007[83]CanadaEnglish (Canada) and French (Canada)02007-11-06November 6, 2007[84]Germany German 02007-11-08November 8, 2007[85]Russia Russian 02007-11-13November 13, 2007 Korea Korean 02008-01-23January 23, 2008IsraelHebrew02008-09-16September 16, 2008IndiaEnglish (India) and Hindi02008-05-07May 7, 2008[86]Czech RepublicCzech02008-10-09October 9, 2008[87]Sweden Swedish 02008-10-22October 22, 2008South AfricaEnglish (South African)02010-05-17May 17, 2010[78]Argentina Spanish 02010-09-08September 8, 2010[79]AlgeriaArabic02011-03-09March 9, 2011[88]EgyptArabic02011-03-09March 9, 2011[88]Saudi ArabiaArabic02011-03-09March 9, 2011[88]TunisiaArabic02011-03-09March 9, 2011[88]JordanArabic02011-03-09March 9, 2011[88]MoroccoArabic02011-03-09March 9, 2011[88]YemenArabic02011-03-09March 9, 2011[88]

The YouTube interface suggests which local version should be chosen on the basis of the IP address of the user. In some cases, the message "This video is not available in your country" may appear because of copyright restrictions or inappropriate content.[89]

The interface of the YouTube website is available in 30 different languages, including Catalan, Danish, Finnish, Greek, Hungarian, Norwegian and Slovene, which do not have local channel versions.[2]

Plans for YouTube to create a local version in Turkey have run into problems, since the Turkish authorities asked YouTube to set up an office in Turkey, which would be subject to Turkish law. YouTube says that it has no intention of doing this, and that its videos are not subject to Turkish law. Turkish authorities have expressed concerns that YouTube has been used to post videos insulting to Mustafa Kemal Atatrk and some material offensive to Muslims.[90][91]

In March 2009, a dispute between YouTube and the British royalty collection agency PRS for Music led to premium music videos being blocked for YouTube users in the United Kingdom. The removal of videos posted by the major record companies occurred after failure to reach agreement on a licensing deal. The dispute was resolved in September 2009.[92] In April 2009, a similar dispute led to the removal of premium music videos for users in Germany.[93]

???????