By: Jack Wylde
Submitted: 2011-08-01 13:53:40 | Word Count: 498
With the advent of science and technology, we have experienced unique inventions and now have made them part of our daily lives. These inventions range from supporting our life in office, home and even in sky above and space. One such invention is digital video broadcasting, which enables us to enjoy many channels and services of various regions in the world. It is because of this, that we can get accustomed to variety of cultures existing in the world today. Digital video broadcasting employs radio frequency spectrum to broadcast the multiplex, in lay man terms, different television channels and various other services bundled together for quick transmission. Radio spectrum provides that single frequency which makes the broadcasting of multiplex easy.
For digital broadcasting, the data both audio and video get compressed in a bundle. This compression is done by using MPEG-2 as a standard. This standard enables efficient bundling or compressing the television channels audio and video data. However, many advanced countries have switched to MPEG-4 standard (AVC for video and AAC for audio), which is a newer technology and works more efficiently to achieve the purpose. When the two standards are compared, MPEG-4 requires less bit rate than MPEG-2, to produce the same quality output. The most amazing aspect about using these standards is that they are nothing but protocols. Hence, it is predicted that MPEG-4 will further get evolved into better and more sophisticated technology which will further improve the performance of digital video broadcasting in future.
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You can also increase the bandwidth of the frequency so as to have a better picture quality of the data. This can be achieved by using statistical multiplexing tools. Usually for any channel, there is a specific bandwidth allocated to it, which is known as constant bit rate encoding. However, it has been quite inefficient in its performance, because it does not provide quality service at crucial times of high load. Thus, the output suffers. Generally, video scenes have a lot of redundancy in their data; hence they require lesser bandwidth capacity to get transferred. This is the reason which is why the entire allocated bandwidth is not used.
Variable bit rate encoding tool is used for multiplex bandwidth allocation. In this statistical multiplexing, each channel gets allocated with a particular bandwidth to enable encoding during any time period. Usually, an allocation is done, but if the service requires more bandwidth, the capacity gets increased to let the complex scenes get transmitted. In this regard, there are two approaches, look ahead and feedback approaches.
It is vital to mention that variable bit rate encoding, when employed with compression standards like MPEG-4, can produce mind-blowing quality of both the sound and video output. It is due to these statistical tools that we are able to get different channels, without making the picture quality suffer. Moreover, with the advent of newer technologies like HDTV series and DVB multiplex, we are in a need to increase the multiplexing capacity of various tools.
Author Resource:-
The Author is the technical director of www.powernetshop.at is an experienced writer for consumer electronic product reviews.
