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Chromecast is a line of digital media players developed by Google. Designed as small dongles, the devices play audio/video content on a high-definition television or home audio system by directly streaming it via Wi-Fi from the Internet or a local network. Users select the media to play using mobile apps and web apps that support the Google Cast technology. Alternatively, content can be mirrored from the Google Chrome web browser running on a personal computer, as well as from the screen of some Android devices. The first-generation Chromecast, a video streaming device, was announced on July 24, 2013, and made available for purchase on the same day in the United States for US$35. The Google Cast SDK was released on February 3, 2014, allowing third parties to modify their software to work with Chromecast. According to Google, over 20,000 Google Cast–ready apps are available, as of May 2015. Chromecast was favorably received by critics, who praised its simplicity and potential for future app support. Over 20 million units have sold globally since launch, and it was the best-selling streaming device in the United States in 2014, according to NPD Group. From Chromecast's launch to May 2015, it handled more than 1.5 billion stream requests. The second-generation Chromecast and audio-only model called Chromecast Audio were released in September 2015. ==Features and operation== Chromecast devices are dongles that are powered by connecting the device's micro-USB port to an external power supply or a USB port. Video-capable Chromecasts plug into the HDMI port of a high-definition television or monitor, while the audio-only model plugs into a 3.5 millimeter audio jack or mini-TOSLINK socket. By default, Chromecasts connect to the Internet through a Wi-Fi connection to the user's local network; a standalone Ethernet adapter/USB power supply, introduced in July 2015 for US$15, allows a wired connection. Chromecast offers two methods to stream content to a television: the first employs mobile apps and web apps that support the Google Cast technology; the second allows mirroring of content displayed by the web browser Google Chrome running on a personal computer, as well as content displayed on some Android devices. In both cases, playback is initiated through the "cast" button on the controlling device. If the television's HDMI ports support the Consumer Electronics Control (CEC) feature, pressing the cast button will also result in the Chromecast automatically turning on the TV and switching the television's active audio/video input using the CEC command "One Touch Playback". * The primary method of playing media on the device is through Google Cast–enabled mobile apps and web apps, which control program selection, playback, and volume. The Chromecast itself streams the media from the web within a local version of the Chrome browser, thus freeing the controlling device up for other tasks, such as answering a call or using another application, without disrupting playback. Mobile apps enabled for Chromecast are available for both Android 4.1+ and iOS 7.0+; web apps enabled for Chromecast are available on computers running Google Chrome (on Microsoft Windows 7+, Mac OS 10.7+, and Chrome OS for Chromebooks running Chrome 28+) through the installation of the "Cast extension" in the browser.〔(【引用サイトリンク】title=GET STARTED WITH CHROMECAST: What's Under the Hood? – Chromecast Help )〕 Streamed content can be Internet-based, as provided by specific apps, or reside on the controlling device's local storage. Apps that provide access to the latter include Castbox, AllCast, Avia, and Plex, as well as the Android version of Google Photos. * Content can also be mirrored from a tab of the Chrome browser (with the Cast extension) on a personal computer or from the screen of some Android devices. In the case of "tab casting", the quality of the image depends on the processing power of the device, and minimum system requirements apply to video streaming. Content that uses plug-ins, such as Silverlight and QuickTime, does not fully work, as the stream may lack sound or image. Google lists the feature as beta.〔 Similarly, screen images mirrored from Android devices are typically degraded, reflecting the fact that video displayed on the smaller screens of tablets and smartphones is usually downscaled.〔 When no content is streamed, Chromecast displays a user-personalized content feed called "Backdrop" that can include featured and personal photos, artwork, weather, satellite images, weather forecasts, and news.〔 〕 Users' controlling devices previously needed to be connected to the same Wi-Fi network as the Chromecast to cast content, until the addition of a "guest mode" feature on December 10, 2014. When enabled, the feature allows the controlling devices to discover a nearby Chromecast by detecting ultrasonic sounds emitted by the television to which the Chromecast is connected; alternatively, the controlling device can be paired with the Chromecast over the Internet using a four-digit PIN code provided on screen. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chromecast」の詳細全文を読む スポンサード リンク
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