Mpeg 4 is now in the application identification stage

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Unformatted text preview: compression is applied to these frames. 3. Each frame is then divided into a series of blocks of 8 x 8 pixels. 4. DCT transformation is then applied to each such 8x8 block of pixels to exploit spatial redundancy. 5. The resulting DCT coefficients (the 64 frequency components in each block) are then scalar quantized using a quantization table (Q-table). 6. The resulting 2-D output of quantization is then ordered in a zigzag sequence, creating a bit stream with zero value coefficients close to the end. 7. Run-length encoding is then applied to the zeros of the zigzag sequence. 8. Finally, variable-length encoding is applied on the run-length coded stream to obtain the MPEG compressed video stream. MPEG standard has the following versions: 1. MPEG-1. The MPEG-1 standard was developed in response to industry needs for an efficient way of storing and retrieving video information on digital storage media. One such inexpensive medium being the CD-ROM, the first version of MPEG, MPEG-1, was targeted at CD-ROM and applicatioins at a bit rate of about 1.5 Mb/s. Although the MPEG-1 standard was developed with CD-ROM in mind, other storage and transmission media can include DAT, Winchester disk, optical disk, ISDN and LAN. In fact, the data rate is variable and all decoders must be able to decode at rates up to 1.856 Mb/s. The video is strictly progressive (i.e., noninterlaced) and picture quality is equivalent to VHS. 2. MPEG-2. The MPEG-2 standard was developed to provide the capability of compressing, coding, and transmitting high-quality, multichannel, multimedia signals over broad-band networks. It addresses high-quality coding for all digital transmissions of broadcast-TV-quality video at data rates of 2-15 Mb/s. Its major applications include digital storage media, digital television (including HDTV), broadcasting over cable, satellite, and other broadcast channels, and other communications applications. Since MPEG-2 was designed mainly as a transmission standard, it supports...
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This document was uploaded on 04/07/2014.

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