Streaming

Streaming media enables real-time or on-demand access to audio, video, and multimedia content via the Internet or an intranet. Streaming media is transmitted by a specialized media server

Application, and is processed and played back by a client player application, as it is received, leaving behind no residual copy of the content on the receiving device.

It is a technique for transferring data so that it can be processed as a steady and continuous stream. Streaming technologies are becoming increasingly important with the growth of the Internet because most users do not have fast enough access to download large multimedia files quickly. With streaming, the client browser or plug-in can start displaying the data before the entire file has been transmitted.For streaming to work, the client side receiving the data must be able to collect the data and send it as a steady stream to the application that is processing the data and converting it to sound or pictures. This means that if the streaming client receives the data more quickly than required, it needs to save the excess data in a buffer. If the data doesn't come quickly enough, however, the presentation of the data will not be smooth.

Streaming media adds engaging motion and sound to the Web experience, increasing site stickiness, interactivity, and retention. Streaming allows timely, dynamic content to be seen by a larger, even global audience, helping to cost-effectively disseminate information, to address new markets, and to bring your corporate culture closer to far-reaching constituencies. Streaming in its truest form, can help to protect video content from being “pirated” and misused. Streaming media is no longer merely a promise. Streaming is here today. This Primer won’t tell you everything about this rapidly emerging technology, but it will give you an overview of the opportunities and the pitfalls, the costs, and the basics. If you are a complete beginner, you’ll find out how easy it can be to edit, encode, and integrate streaming video into your own Web site. And,  if you are already creating video productions, this Primer will introduce you to the  state-of-the-art streaming media technologies you can use to extend your content to the Web, and to confi dently share your productions online.

Data streaming commonly seen in forms of audio and video streaming, is when a multimedia File can be played back without being completely downloaded first. However certain audio and video file like real audio and quick time documents can be streaming files, meaning u can watch a video or listen to a sound file while its being downloaded to your computer.

Major streaming video and streaming media technologies include Real System G2 from Real Network, Microsoft Windows Media Technologies and VDO. Microsoft's approach uses the standard MPEG compression algorithm for video. The other approaches use proprietary algorithms. Microsoft's technology offers streaming audio at up to 96 Kbps and streaming video at up to 8 Mbps However, for most Web users, the streaming video will be limited to the data rates of the connection (for example, up to 128 Kbps with an ISDN connection).

3. THERE ARE TWO BASIC TYPES OF STREAMING MEDIA     CLIENTS:

3.1. Java clients

Java clients quickly download a Java applet to the user’s machine before the streaming content begins, so that any Java-enabled browser can play back the stream. Java clients can provide a virtually transparent experience for the end user, playing content that appears to be seamlessly embedded into a Web page, a banner, or an e-mail, without invoking a pop-up window for a plug-in player that may interrupt the experience. Java clients do not, typically, offer the full range of end-user controls provided by plug-in clients

 3.2. Plug-in clients

            A plug-in is an application that adds functionality to your Web browser. In the case of a media player, the plug-in provides the client software needed to play back and control media that is either downloaded or streamed to the browser. The three major streaming media architectures use plug-in clients.

4. METHODS

4.1. Streaming the RDP packets

        RDP stands for Remote Desktop Protocol , which is used in the Remote Desktop connection in Windows XP. The Windows Terminal Server generates screen updates as bitmap images and other 2D primitives, compress them , and transfer to client.

        To achieve the presentation ability, we make use of the Terminal Service, and streaming those desktop updates to more then 1 client.

         Even though the bandwidth usage of RDP is lower then other thin client systems , it can still be lower by applying lossy compression, wavelet transform.

5. STREAMING AUDIO

5.1. DEFINITION

It's a method of delivering an audio signal to your computer over the Internet, and differs from the "normal" method of receiving Internet audio in one important way: instead of having to download a ".wav", ".au" or other type of file completely before being able to listen to it, you hear the sound as it arrives at your computer, and therefore do not have to wait for a complete download (which would be difficult with a live broadcast anyway!).  As the data arrives it is buffered for a few seconds and then playback begins. As the audio is playing, more data is constantly arriving (or streaming), and as long as you are receiving a constant stream of data, you should hear constant audio. Obviously you'll need a soundcard, speakers (or headphones) and the appropriate software for this all to work. Think of a bucket (the buffer) with a hole in the bottom, being topped up with water (the data). As long as there is water in the bucket, it will continue to pour out of the hole, and will do this as long as there is water in the bucket. Similarly, as long as there is data in the buffer, you will continue to hear sound.

5.2.  Working Examples:

 Look at the Multiple Track Streaming Example (36 track playlist) on the main page of   my site to see another more detailed and practical example / application of the same streaming technique described in this article.

 When the Automated Jukebox starts you can either allow the jukebox to automatically advance and play through each song in sequence without user intervention, or you may jump to any song you like by clicking on the respective song link. 

12. CONCLUSION

On-demand software delivery is a hot topic in the computer world. They can virtualize the local installation and stream the applications -- and even the operating system -- from a central distribution server in real time. The Citrix technologies are using streaming technology to manage the desktop application environments in the company's 300-seat call center.

Application streaming technology takes advantage of the fact that LANs are getting faster additional application and operating system components are fetched as needed once the system is up and running. As a result of this applications can be maintained and updated on central servers.

The proliferation of fat clients and distributed applications has been the result of a natural progression from centralized, inflexible computing to decentralized computing focused on user productivity. Managing this new world has been difficult for IT and Security teams. This, coupled with the rising cost of licensing and Help Desk operations, is causing organizations to look for a ‘better way.’