Masood Parwez Shabnam, Assistant Manager-Broadcast Technical, DishTV India Ltd.
The media that is continuously received and presented to end user.
Video streaming is a term applied to the compression and buffering techniques that allow one to transmit and view video in real time via Internet.
Video has been an important media for communication and entertainment for many decades. Initially, video was captured and transmitted in analog form. The advent of digital integrated circuits and computers led to the digitization of video, and it enabled a revolution in the compression and communication of video. It became an important area of research in the late 1980s and 1990s, and enabled a variety of applications including video storage on DVDs and video-CDs, video broadcast over digital cable, satellite and terrestrial (over-the-air) digital television (DTV), and videoconferencing and videophone over circuit-switched networks. The growth and popularity of Internet in the mid-1990s motivated video communication over the best-effort packet networks. It is complicated by factors like time-varying bandwidth, delay, and losses. The challenges that make simultaneous delivery and video streaming of pre-encoded or live video are examined here.
What Is Video Streaming and How It Works
The invention of streaming media has removed many obstacles. It uses an age-old concept: buffering to make viable the playback of multimedia content while it is being downloaded. Buffer holds a reservoir of content sufficiently large to smooth out the bumps in playback that may be caused by momentary server sluggishness or network congestions. Buffering allows streaming to maintain continuous playing of video despite the occasional burp in network delivery. Streaming media combines the concept of buffered real-time playback with compression to make viable what once might have been considered impossible– delivering to hundreds or even thousands of viewers simultaneously. In video, there is so much information in full-frame, full-motion video content. Nonetheless, real-time streaming of video has improved as new "codecs" are designed with better compression. It is nowhere near the quality of conventional television, but it is serviceable for some applications, and it will continue to improve.
Basic Steps in Sending out Video Content
- Create the content. It might be a recording or a live event.
- Encode the content into the streaming format.
After ditizing, the file is placed on a streaming server to await requests for playback. The streaming server has streaming software installed. The content is especially encoded and placed in a file in the streaming server's file hierarchy. The server waits for a request from the user for streaming a particular document. When a user clicks the URL, it sends a request to the streaming server. The streaming server finds relevant content and prepares to send the file over the Internet. As the file transmission begins, the contents are broken into "packets"; each packet is sent as soon as it is prepared.
The user's browser such as the Real Player places each packet into its buffer as it arrives, and when the buffer is sufficiently full, the plugin starts playing the content.
Vendors who are providing streaming solutions are:
RealSystem G2 Production Guide
RealServer Administration Guide
Basic Problems in Video Streaming
- Delay jitter
- Loss rate
Real Networks offers a "Basic" server with up to 25 simultaneous streams for free. A single entity can install one such server. Schools, libraries, governmental, and other nonprofit organizations may be able to serve for free.
A single "stream" is consumed for each user who connects to the streaming server for content at a time. If 1000 people are connected, a license for 1000 streams is required.