syntax element with an associated syntax category and descriptor or can be an expression used to specify conditions for the existence, type, and quantity of syntax elements, as in the following two examples */ syntax_element ue(v) conditioning statement 1* A group of statements enclosed in curly brackets is a compound statement and is treated functionally as a single statement. */ statement statement 1* A "while" structure specifies a test of whether a condition is true, and if true, specifies evaluation of a statement (or compound statement) repeatedly until the condition is no longer true */ while( condition ) statement 1* A "do while" structure specifies evaluation of a statement once, followed by a test of whether a condition is true, and if true, specifies repeated evaluation of the statement until the condition is no longer true */ statement while( condition) 1* An "if else" structure specifies a test of whether a condition is true, and if the condition is true, specifies evaluation of a primary statement, otherwise, specifies evaluation of an alternative statement. The "else" part of the structure and the associated alternative statement is omitted if no alternative statement evaluation is needed */ if( condition ) primary statement alternative statement Rec. ITU-T H.264 (01/2012) 1* A "for" structure specifies evaluation of an initial statement, followed by a test of a condition, and if the condition is true, specifies repeated evaluation of a primary statement followed by a subsequent statement until the condition is no longer true. */ for( initial statement; condition; subsequent statement) primary statement Specification of syntax functions, categories, and descriptors The functions presented here are used in the syntactical description. These functions assume the existence of a bitstream pointer with an indication of the position of the next bit to be read by the decoding process from the bitstream. byte_aligned() is specified as follows: If the current position in the bitstream is on a byte boundary,