Hypothetical reference decoder for compressed image and video

A method of processing a bitstream, said bitstream having a plurality of compressed pictures and a plurality of messages, said method comprising:

• computing a bit rate and a buffer size from bit rate information and buffer size information in said bitstream;
• computing, from a buffering period message, a picture removal time associated with the first picture following said buffering period message;
• computing a picture removal time of said compressed picture from a picture message for each compressed picture in the bitstream following said first picture;
• wherein, for each compressed picture following said buffering period message, said method further comprising:
• counting the number of bits representing said compressed picture;
• computing an initial arrival time and a final arrival time of said compressed picture, wherein said initial arrival time is equal to an earlier of said final arrival time of the immediately previous compressed picture or equal to a sum of a fixed time plus a sum of removal delays of all of said compressed pictures between said first compressed picture following said buffering period message and said compressed picture, including said compressed picture, and wherein said final arrival time is equal a sum of said initial arrival time and a time calculated based on the number of bits associated with said compressed picture at said bit rate;
• and
• verifying that a difference between said final removal time and said initial arrival time does not exceed the time for reaching said buffer size at said bit rate.

A system for processing a bitstream, said bitstream having a plurality of compressed pictures and a plurality of messages, said system comprising:

• a decoder configured to receive said bitstream, said decoder having a pre-decoder buffer configured to buffer said bitstream;
• wherein said system performs:
• computing a bit rate and a buffer size from bit rate information and buffer size information in said bitstream;
• computing, from a buffering period message, a picture removal time associated with the first picture following said buffering period message;
• computing a picture removal time of said compressed picture from a picture message for each compressed picture in the bitstream following said first picture;
• wherein, for each compressed picture following said buffering period message, said method further comprising:
• counting the number of bits representing said compressed picture;
• computing an initial arrival time and a final arrival time of said compressed picture, wherein said initial arrival time is equal to an earlier of said final arrival time of the immediately previous compressed picture or equal to a sum of a fixed time plus a sum of removal delays of all of said compressed pictures, between said first compressed picture following said buffering period message and said compressed picture, including said compressed picture, and wherein said final arrival time is equal a sum of said initial arrival time and a time calculated based on the number of bits associated with said compressed picture at said bit rate;
• and
• verifying that a difference between said final removal time and said initial arrival time does not exceed the time for reaching said buffer size at said bit rate.