The Moving Picture Experts Group

What are the assumptions of the MPEG-4 timing model?

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For applications involving real-time transmission, the timing model adopted by MPEG-4 assumes a constant end-to-end delay from the output of the encoder to the input of the decoder. This is only done so that a well defined and verifiably correct model is employed. It does not mean that MPEG-4 content cannot be transmitted over variable delay networks.