Picture Output Timing Signaling for HRD-Free Video Bitstreams
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to a significant increase in transmission and storage costs due to the rise in the amount of transmitted information or bits, necessitating high-efficient image compression technology.
Innovation Solution
An image encoding/decoding method and apparatus that improves encoding/decoding efficiency by signaling picture output timing information through flags specifying the presence of HRD parameters and constraining temporal distances between consecutive pictures, allowing for efficient processing of bitstreams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If image resolution and quality are improved, then image quality is enhanced, but transmission cost and storage cost increase
Solution Approach 1:
The patent extracts only the essential timing information needed for decoding by introducing compact flag parameters (general_hrd_params_present_flag, vcl_hrd_params_present_flag, fixed_pic_rate_general_flag) that indicate the presence or absence of HRD parameters. This extraction approach transmits only the critical timing data without sending redundant information, thereby maintaining high image quality while reducing the amount of transmitted data and associated costs
2Loss of information
If HRD parameters are fully signaled for all pictures, then output timing information is complete, but bitstream size increases
Solution Approach 1:
The patent creates a universal signaling mechanism where a single flag structure (general_hrd_params_present_flag) can indicate the presence of HRD parameters that apply to multiple pictures or all pictures in a sequence. This multi-functional approach allows the same flag to serve different purposes depending on its value, enabling complete timing information to be conveyed for all necessary pictures while avoiding redundant signaling, thus reducing overall bitstream size
Solution Approach 2:
The patent applies partial signaling by using flags to indicate only when HRD parameters are present or absent, rather than explicitly signaling complete parameter sets for every picture. The fixed_pic_rate_general_flag provides a default assumption that applies when full parameter signaling is not present, allowing the system to use partial information (flags) to represent complete timing behavior, thereby reducing bitstream size while maintaining information completeness
Data Source
AI summary
An image encoding/decoding method and apparatus are provided. An image decoding method according to the present disclosure may comprise obtaining a first flag specifying whether a network abstraction layer (NAL) hypothetical reference decoder (HRD) parameter is present in a bitstream and a second flag specifying whether a video coding layer (VCL) HRD parameter is present in the bitstream, obtaining a third flag specifying whether a temporal distance between output times of consecutive pictures in the bitstream has a fixed value, deriving output times of the pictures in the bitstream, based on at least one of the first flag, the second flag or the third flag, and processing the pictures in the bitstream based on the derived output times. Based on the first flag having a second value specifying that the NAL HRD parameter is not present in the bitstream and the second flag having a second value specifying that the VCL HRD parameter is not present in the bitstream, it may be constrained that the third flag has a first value specifying that the temporal distance between the output times of the consecutive pictures in the bitstream has a fixed value.