Methods and systems for entropy coder initialization

A method for decoding a video frame in a video sequence, the method comprising:

• receiving a slice header and information including:
• (i) first information indicating a number of second regions in a first region, and (ii) second information indicating an offset of an i-th second region from an (i−1)th second region in a bitstream, wherein the video frame includes one or more of the first regions and one or more the second regions;
• identifying a slice type of a slice;
• receiving a flag with only one of:
• (i) a first value indicating first initialization information and (ii) a second value indicating second initialization information;
• initializing a Context-Adaptive Binary Arithmetic Coding (CABAC) context associated with the slice type using the initialization method which is selected using the identified slice type and the received flag;
• and
• decoding the video frame using the identified slice type and the received flag;
• wherein
• in a case that the identified slice type indicates a B-slice type and the value of the flag is equal to the first value, the step of initializing the CABAC context associated with the slice type uses a first initialization method;
• and
• in a case that the identified slice type indicates the B-slice type and the value of the flag is equal to the second value, the step of initializing the CABAC context associated with the slice type uses a second initialization method.