MPEG je jedna od najpopularnijih serija standarda za video/audiokompresiju, pogodnih za različite aplikacije, ali temeljenih na sličnim principima. Ako se MPEG komprimirani videosignal treba prenijeti do udaljenog korisnika, na raspolaganju su različite mrežne tehnologije, primjerice ATM i IP, pri čemu je od interesa osigurati potrebnu kvalitetu usluge, i to uporabom najekonomičnije tehnologije na raspolaganju. Da bi se to ostvarilo, potrebno je nadzirati parametre kvalitete usluge na razini relevantne prijenosne tehnologije (kakvi su npr. varijacije kašnjenja i gubitak podatkovnih jedinica protokola kojim se koristi – okvira, ćelija ili paketa), i odabrati odgovarajuće metode za njihovo držanje na razini koju (zbog smanjenja redundancije) osjetljivi komprimirani MPEG niz može tolerirati. S tim u vezi, u ovome je radu, s jedne strane, predstavljen primjer tehnika mjerenja i testiranja prijenosnog sustava (ATM), a s druge strane, dostignuta je perceptualna kvaliteta prenesenoga MPEG signala, a zatim su doneseni odgovarajući zaključci o razini utjecaja gubitaka podataka u mreži na kvalitetu primljenog videosignala.MPEG is one of the most popular families of audio/video compression techniques, suitable for different applications but still based on similar principles. If an MPEG compressed video signal is to be transmitted to the remote user, various network technologies are available, such as eg. ATM and IP, where it is of interest to provide the needed quality of service (QoS) still using the most economical technology available. In order to accomplish that goal, it is necessary to monitor the QoS parameters of the relevant transmission technology (such as eg. delay variation and loss of protocol data units – frames, cells and packets), and then select appropriate methods for keeping the parameters values at the level that the vulnerable (due to reduction of the redundancy) compressed MPEG stream can tolerate. With this respect, in this paper, from one point of view, the example of test and measurement techniques as applied to the transmission system (ATM), and from another point of view, the achieved perceptual quality of the transmitted MPEG signal, have been considered, and the appropriate conclusions made about the degree of the impact of network packet loss on the quality of the received video signal
