Best Wireless Media Centers

MP3 got its name on the international scene way back in 1995 as the file-name extension for MPEG Layer 3. It was selected as the audio format for the World Space satellite digital audio broadcasting system. The era of MP3 really began with introduction of Diamond Multimedia Rio in the U.S and Saehan Information System's MPMAN in Korea, the first of the headphone stereos using solid-state flash memory to store playing compressed MP3 memory files.

MP3 Phenomenon

With the passage of time the popularity of MP3 started shooting up and companies one after another fell for it resulting in development of audio codec for personal computers. In United States the first MP3 was CD players those played MP3 encoded 5-inch CDs. Since then MP3 has become a cultural phenomenon. Millions of computers and computer accessories with MP3 compatibility is sold around the world. The capability to store huge collection of songs on a small portable player, search them by category and even generating play lists automatically has also caused a music boom.

MP3 is not merely a technology. It has made a great cultural contribution by connecting musicians, speakers and creators on one side with music lovers, listeners and audience on the other.

Advent of Digital Media and Digital Audio

Digital audio comprises of audio signals stored in a digital format. This involves analogue to digital conversion (ADC) and digital to analogue conversion (DAC). ADC is concerned with sampling and quantifying analogue audio signal. DAC requires conversion of digital audio to a line level signal for playback of distribution.

Two more items, digital audio system is related to, are audio signal processing like applying equalization, reverberation and sample rate conversion and storage, retrieval, and transmission of digital signals in audio format. The audio formats in which digital information is transmitted are CD, MP3,Ogg Vorbis etc.

Why Digital Technology

Since the advantage in sound recording, its regulation, mass production and distribution is much more compared to any traditional system, digital technology is fast emerging as the most popular sound recording system. The use of compression algorithm further enhances its usefulness since large amount of data can now be put into a compressed file and put in storage. The technology has also been highly successful in reducing the cost of distribution.

While analogue audio music storage and reproduction has now replaced the older systems like gramophone records, compact cassette, and wax cylinders, the principles remain the same as that of human hearing. Sounds are first captured in the form of mechanical energy waves in air and then transformed into an electrical energy by a microphone transducer. So the fundamental wave like characteristics remains unchanged during storage, transformation, duplication, and amplification. However, loss of data in transmission is one major drawback.

Digital audio chain on the other hand begins when sound is converted into electrical signals. These are normally in the form of on/off pulses. The advantages are that it can be copied or transmitted much more conveniently and the loss of information during transmission is minimized. Even when signals pass many times through cables, mixing desks and other processing equipment the loss is minimized. The final stage is to mix down the signals onto a two-track master for manufacturing.

Digital video

Video ordinarily refers to various storage formats for moving pictures. Digital video formats are DVD, QuickTime, and MPEG-4, and analog videotapes. The analog videotapes include VHS and Betamax. Videos can be recorded for transmission either through mechanical cameras or digital cameras. At the end of the 20th century 3D video came up to highly enhance the performance of digital video. Frame rate, the number of still pictures per unit time of video, ranges between 6 to 8 frames per second. For new professional digital cameras like PAL, SECAM, and NSC the standard is between 25 frames per second to 30 frames per second. Films are shot at 24 frames per second and to achieve the illusion of movement the minimum rate is 10 frames per second. Video can also be interlaced or progressive to achieve good visual quality within the limitations of a narrow bandwidth.

Proliferation of Digital Cameras

Development of inexpensive digital cameras and easy to use image editing software has brought digital photography to mainstream use. Along with proliferation of digital cameras, associated software and services have emerged on the seen allowing user to organize and catalog hundreds of digital photographs stored in their PC. The photos are not only stored but shared too. Such sharing is possible on the Internet too. Digital cameras today include digital still camera, DSP SoC design methodology compatible digital camera, spectral based color image digital camera etc. Digital still cameras (DSC) are quickly flourishing as technology is daily adding new capabilities to improve the quality of the image and reducing cost in the consumption of power while enhancing the picture storage capacity.

Streaming Bandwidth and Storage

Streaming bandwidth is the basis for calculation of media storage size by using the formula of storage size = length in seconds X bit rate in kilobytes per second whole divided by 8,388.608. One hour of vide encoded in 300 Kilobytes per second will be 128.7 Mega bytes of storage. If the files is stored on a server for streaming and is viewed by 1000 people, the requirement is calculated at 300 kilobytes per second for 1000 persons coming to around 300 Mega bytes of bandwidth which again is equivalent to 125.68 Gigabytes per hour.

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