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MPEG-2 ZERO CELL LOSS IN ATM NETWORKS

 

TITLE MPEG-2 ZERO CELL LOSS IN ATM NETWORKS.
AUTHOR THAMMANOON CHARMJUREE
DEGREE MASTER OF SCIENCE PROGRAMME IN COMPUTER SCIENCE
FACULTY FACULTY OF SCIENCE
ADVISOR SUPACHAI TANGWONGSAN
CO-ADVISOR DAMRAS WONGSAWANG
 
ABSTRACT
This thesis presents a model of MPEG-2 zero cell loss in ATM networks. It is a mean for reducing or minimizing the error/loss of MPEG-2 data when transmitted over an ATM network. A typical event of data loss in an ATM network, involving the loss of several ATM cells, which contain a little portion of a single picture/frame, can be extended into areas some tens of times bigger over several consecutive pictures. Thus, it is necessary to have coded video at the receiving side to be detected and concealed before being displayed. Then, there should be some sort of error recovery and/or concealment techniques in order to remedy the situation. The objective is to define the causes and characteristics of MPEG-2 cell loss over an ATM network, then study the affected frame type (I-frame, P-frame, B-frame, and the combination of I, P, B-frames), and find out the location of error/loss in MPEG-2 video. The main issue is to reduce/combat the magnitude of errors and cell loss in the MPEG-2 video stream and then make them less noticeable to the viewer. Thus, error detection and concealment is a proposed technique to minimize the impact of missing/lost MPEG-2 data. This model consists of three major processes: error detection, error concealment, and video quality assessment. Error detection: The process for MPEG-2 error detection is embedded in MPEG-2 the decoder, which performs after getting an MPEG-2 frame sequence from the ATM network. Error concealment: The process for MPEG-2 error concealment, is to get a macroblock error map from error detection. Finally, video quality assessment is the process for determining the quality of the MPEG-2 video. The experimental results confirm that we are able not only to detect and conceal the MPEG-2 distortion area, but also to improve the quality of the picture in terms of gain in PSNR (Peak Signal to Noise Ratio) value and also the efficiency in time of processing.
KEYWORD MPEG-2 OVER ATM NETWORKS / ERROR DETECTION /ERROR CONCEALMENT / TEMPORAL ERROR CONCEALMENT / SPATIAL ERROR CONCEALMENT / TEMPORAL INTERPOLATION

 

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