Video coding system with low delay and method of operation thereof

A decoding apparatus, comprising:

• at least one processor configured to:
• extract, from an encoded bit stream, a low delay flag, a network abstraction layer (NAL) hypothetical reference decode (HRD) parameters present flag, and a video coding layer (VCL) HRD parameters present flag;
• extract a sublayer from the encoded bit stream based on the extracted low delay flag, the network abstraction layer (NAL) hypothetical reference decode (HRD) parameters present flag, and the video coding layer (VCL) HRD parameters present flag;
• and
• decode the encoded bit stream based on the extracted sublayer, wherein
• the low delay flag is, as a syntax of the encoded bit stream, present before a hypothetical reference decode (HRD) parameters structure call, and
• the hypothetical reference decode (HRD) parameters structure call is based on at least one of the network abstraction layer (NAL) hypothetical reference decode (HRD) parameters present flag or the video coding layer (VCL) HRD parameters present flag.