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One of the commonly used technologies for streaming solution is Microsoft Windows Media Technologies (WMT). This gadget is very important for finding solutions for playing back the media internet files, creating and distributing. In its operation the WMT utilizes the applications which are made by the end user for instance the server and the window media server. Pre-positioned and live window media files are disseminated onto content Delivery Network by employing server capabilities which are found on the content engine as well as the WMT caching proxy. The WMT supports a proxy feature which is very basic in receiving incoming WMT requests of users. Therefore WMT serves as an intermediate between the user or client and the server. On the other hand the WMT receives and serves the client streaming requests to the Microsoft Media Server and HTTP protocol. Window Media Technologies uses Microsoft Media Server for communication which is usually done between the servers and the players. By using the WMT requests can be served via the cache without going to the original server.
The Window Media Technologies are advantageous since they accept requests which have been intercepted transparently. This can be achievable through L4 directs or by use of WCCP besides manual proxy requests. Separation or splitting of direct streams is made possible through the use of WMT caching proxy. Therefore multiple clients can be served at the same time when the information or the files are split. Frequent caching which assesses files near the user offers quality streams and as a result network bandwidth is saved. Cacheable streams can be stored on the media file system when WMT is in use. For this case a client can be sent a file which is not yet cached because it can be retrieved by the proxy fetches. Whatever the client receives is usually maintained in the original server because it’s important in monitoring the files which have been received by the user. Therefore accounting and tracking is made possible by maintaining the sent files within the original server (Streaming par. 7).
Video codec. Video compression as well as decompression is made possible by employing a video codec. One of the most important aspects in video compression is ensuring quality measurements. Lossy data compression is what is mainly looked in case there is need for video compression. Compact disc is commonly used as replacement for audios which are analog. Video compression is aimed at developing videos whichclosely resembles the originality of the main source. Simultaneous delivery of the streamed files in small file size is made possible by compressing video. There are number of factors which are closely looked at when comparing video codec. The quality of the video per bitrate is the initial important aspect which is considered. Other factors include the performance characteristics which covers concepts like decompression and compression speed, the supported resolutions and supported profiles among other concepts.
The general characteristics of the soft ware in use are critically analyzed for instance the manufacture, version number, and date of release and price of the codec among other important aspects. The application area of the specific codec is looked at since all codec’s do not operate within the same area. Some of the characteristics which matter as far as determination of the operation area is concerned include video conferencing resume and MPEG-4 CD or DVD compressions presume. There are many detailed factors which are critically analyzed under the two specified areas. The quality of the codec heavily relies on the compression format of the specific codec in use. Since a codec is not in itself a format therefore multiple codec are usually used under compression specification. For this case quality and size is not achieved by employing MPEG-1codecs compared to H.264 specification codecs (Sjoberg et al 14).
Another important aspect is the realization that every codec can give different quality depending on the video sequence frames that have been used. The most common feature in all codecs is the presence of a bitrate control strategy which greatly determines the quality of the existing vibrates on each frame. For this reason the difference that exists between the constant bit rates (CBR) and the variable bit rate (VBR) determines the trade off between the consistent variable and the quality of the frame in use. The trade off is important and necessary in some types of applications. On the other hand there exists codecs which differentiate between the various types of frames in use. For instance non key frames and key frames are separated basing on there underlying importance as far as visual quality and the range of compression is concerned. The other quality which is looked at is the pre-filtrations; all available codecs have pre-filtrations and these gadgets are essential in quality determination.
Long clips usually require sequences which have nott undergone much of compression. This is very important when using CBR because there is many differences in the frames basing on the levels compression which might have been done in order to gain constant vibrate. Therefore a number of clips can be used to differently in a single long clip. Techniques which are used to evaluate videos are usually mathematical models. These models are normally used to approximate the quality assessment results. There are objective measurements which are usually used in determining the quality of the computer program. Classification is usually done on the basis of the original video signal since it’s usually of high quality. The methods which are used are classified in three namely; no reference methods, full reference and reduced reference methods (Sjoberg et al 12).
The metrics which are manly used in the full reference include peak signal to noise ratio (PSNR). This metric has been widely used in the last two decades for video quality. The underlying challenge in using this metric is the limitations of the metric validity. Validity is only concluded when a codec that is similar to the content is used. Structural similarity is a recent innovation which is much better than the peak signal to noise ratio. Because of the underlying complexities a number of metrics have been suggested though they are not still widely used. The comparison method which is widely used is the RD curve or rate/distortion chart. In this curve the X-axis is usually used for the bitrate whereas the Y-axis for the metric value. The NR metrics which are commonly used include the blocking artefacts and the blurring measure.
Video quality subjection is usually conducted on the basis of the viewer’s perception as well as their opinion on the sequence of the specific video. This process is very expensive in terms of the employed human resources as well as the consumed time. There are a number of methods which are useful in subjective video quality. A few of these methods have been standardized though they are simply referred to as ITU-R recommendation BT. 500. An example of the subjective video quality method which has been standardized is the Double Stimulus Impairment Scale. A simple process is usually employed since the expert is issued with a reference video which is impaired and another similar video after which he is requested to vote the video which he was issued on the second time using a scale which is impaired. Low picture resolutions are determined using QCIF, CIF and VGA.