(T) Video is everywhere. All over the Web with YouTube. On our iPhone and Android. And, now broadcast video and the Web are merging. On mobile networks, video is the dominant driver of the Internet traffic and can produce up to 40% of the traffic. Most of the video traffic, at any given time, is driven by a small number of videos that are downloaded by a very large number of users. One video user consumes as much bandwidth as fifteen Web users. Most videos are watched for a few seconds and most users do not finish watching the videos they downloaded.
There have been many new media technologies over the last year to feed the growth of the media content – following is a quick review of them:
New Video Formats
Video formats (or containers or wrappers) define the file structures and properties to store the media. Ogg, a new open source royalty-free media container, maintained by the Xiph.Org foundation is being supported in open source browsers such as Firefox, that have a built-in Ogg player. Ogg integrates Theora as the video codec and Vorbis as the audio codec that are both being recommended into the HTML 5 draft specification.
In parallel to Ogg, Google has launched earlier this year, WebM, an open source royalty-free media container, based on the Matroska media container that integrates Google On2 VP8 video codec and the Vorbis audio codec from Xiph.Org.
New Video Streaming Protocols
Streaming media enables to deliver to the user device the media as a steady continuous stream, allowing playback of the media to proceed while the subsequent data of the media is being received. With live media streaming, the media is captured, compressed and transmitted on the fly; versus video-on-demand (VOD) media streaming that previously records and compresses the media. The two incumbent streaming protocols have been RTSP and Adobe RTMP.
RTSP (Real Time Streaming Protocol) originally developed by Netscape and RealNetworks, and defined in the IETF RFC 2326, controls the media sessions between the client and the streaming media server like a VCR with play and pause commands. In most cases, RTSP leverages RTP (Real-Time Transport Protocol), defined in the IETF RFC 3550, for the transport of the media itself.
RTMP (Real Time Messaging Protocol) from Adobe works with Adobe Flash Media Server and Adobe Flash Player Client and is widely used in video Web applications. RTMP maintains a single constant TCP connection and allows for multiple, bidirectional, communication channels to be active simultaneously between the Flash Clients and the Flash Media Server.
One of the major issues of RTSP and RTMP is that both protocols can be blocked by firewalls, although RTMP, to avoid that, can be tunneled into HTTP.
YouTube has pioneered the use of HTTP progressive download in which the video is transported over HTTP and the client can start playing the video before its final download. In order to integrate streaming into HTTP, both Apple and Adobe have recently launched two very similar and competing protocols: Apple HTTP Live Streaming (proposed as an RFC) and Adobe HTTP Dynamic Streaming. Both protocols basically enable the Web server to provide multiple versions of the same media file to the client at different bit-rates. Each version of the file is split into segments of equal duration. The client checks the network bandwidth and chooses accordingly the version of the media file to stream from an index file provided by the server. Apple HTTP Live Streaming supports video encoded in H.264 and audio in HE-ACC and .mp3 formats.
Videos and HTML 5
HTML 5 provides a new tag for video that enables to add to the HTML code an .Ogg, .MP4 or .WebM video. The media player is embedded into the browser which plays natively the media without any specific plug-in. With HTML 5, video rendering is treated as an image rendering. Following is a very simple example of the HTML 5 video tag:
<video width=”320″ height=”240″ controls>
<source src=”pr6.mp4″ type=’video/mp4; codecs=”avc1.42E01E, mp4a.40.2″‘>
<source src=”pr6.webm” type=’video/webm; codecs=”vp8, vorbis”‘>
<source src=”pr6.ogv” type=’video/ogg; codecs=”theora, vorbis”‘>
As a consequence, HTML 5 makes the Adobe Flash Plug-In irrelevant; that is the reason given by Apple to not support it on the iPAD.
The HTML 5 specification does not specify which video formats the browser should support, but .Ogg and .MP4 are the two common ones,
- Apple Safari supports .MP4 only,
- Firefox .Ogg ,and .WebM,
- and Google Chrome .MP4, .Ogg and .WebM.
So in order to have a video watchable across many HTML 5 platforms, a developer might need to encode it in many formats.
Apple TV and Google TV
Last month, Apple released a new version of Apple TV, a small network appliance, that can stream the media content from iTunes, Netflix, YouTube, Flick and MobileMe on an HD TV screen for $99.
Google TV, a very innovative product, is both a software platform that can be built into an HD TV from Sony and an appliance from Logitech. Google TV is based on Google Android O/S and Google Chrome browser along with Adobe Flash Player. Google TV enables complete Web access on the TV set, enables watching TV broadcasting programs and Web browsing at the same time, comes with Mobile Apps, can use an Android phone as the remote and facilitates playlists and recording among many other features. Google TV will also include an open-source API that will enable developers to create widgets. Prices of Sony and Logitech Google TV are ranging in the few hundred dollars and much more expensive than the Apple TV but I would expect them to decrease quickly as Google improves and expands the Google TV in the soon future.
Note: The picture above is Google TV.
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Categories: Video, Audio, and Other Media