WebM

WebM video files play directly in your web browser using a new technology called HTML5. No plug-ins are required, but you must install a web browser that supports WebM files.
WebM은 HTML5 기술을 사용하여 웹 브라우저에서 직접 실행한다. 플로그인은 필요없지만 WebM files을 지원하는 웹 브라우저를 설치해야 한다.

지원하는 웹 브라우저
● Mozilla Firefox 4 Beta 1 and later
● Opera 10.60 and later
● Google Chrome 6 and later
● Chromium nightly trunk build as of 20100520


What is WebM?

WebM is an open, royalty-free, media file format designed for the web.
웹을 위해 디자인 된 오픈, 로열티-프리, 미디어 파일 포맷 

WebM defines the file container structure, video and audio formats. WebM files consist of video streams compressed with the VP8 video codec and audio streams compressed with the Vorbis audio codec. The WebM file structure is based on the Matroska container.
WebM은 파일 컨테이너 구조, 비디오, 오디오 포맷을 정의한다.
WebM 파일 구성 : VP8 비디오 코덱 + Vorbis 오디오 코덱으로 압축한 오디오 스트림 => 비디오 스트림
WebM 파일 구조 : Matroska 컨테이너 기반

Benefits of WebM

Openness and innovation. A key factor in the web's success is that its core technologies such as HTML, HTTP, and TCP/IP are open for anyone to implement and improve. With video being core to the web experience, a high-quality, open video format choice is needed. WebM is 100% free, and open-sourced under a BSD-style license.

Optimized for the web. Serving video on the web is different from traditional broadcast and offline mediums. Existing video formats were designed to serve the needs of these mediums and do it very well. WebM is focused on addressing the unique needs of serving video on the web.

• Low computational footprint to enable playback on any device, including low-power netbooks, handhelds, tablets, etc.*
  
• Simple container format
  
• Highest quality real-time video delivery
  
• Click and encode. Minimal codec profiles, sub-options; when possible, let the encoder make the tough choices.

* Note: The initial developer preview releases of browsers supporting WebM are not yet fully optimized and therefore have a higher computational footprint for screen rendering than we expect for the general releases. The computational efficiencies of WebM are more accurately measured today using the development tools in the VP8 SDKs. Optimizations of the browser implementations are forthcoming

Playing on YouTube

1. Download and install a supported browser (listed below).
2. Start the newly installed browser.
3. Go to www.youtube.com/html5 and enroll in the YouTube HTML5 experiment.
4. Search for a video by keyword. For example, trailers.
5. In the browser's address bar, add &webm=1 to the end of the URL. For example,http://www.youtube.com/results?search_query=trailers&aq=f&webm=1.
6. Press Enter.
7. In the list of videos that appears, click any of the links.
8. The video will play in your browser and display HTML5 webm in the toolbar of the video player.

참고
http://www.webmproject.org/ 
http://wonsuk73.tistory.com/14