Signaling Initial Buffering Parameters for Random Access Playback
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Solution Overview
Problem
Existing electronic devices face challenges in efficiently representing and playing back high-quality digital media due to issues with initial buffering latency and bitstream management, particularly when starting playback at random access points.
Innovation Solution
The systems and methods described involve electronic devices that generate and send messages containing specific buffering parameters, such as initial CPB removal delays, to optimize buffering periods and reduce latency when starting playback at random access points, using modified syntax and semantics in buffering period supplemental enhancement information (SEI) messages and hypothetical reference decoder (HRD) modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If traditional buffering parameters are used for random access playback, then playback can start at random access points, but initial buffering latency is excessive and buffer underflow/overflow occurs
Solution Approach 1:
The patent introduces multiple initial buffering parameters (initial CPB removal delay, initial alternative CPB removal delay, and initial CPB removal delay offset) that can be selectively applied based on the random access point type. These parameter changes enable precise control over buffering behavior, reducing initial buffering latency while preventing buffer underflow or overflow through appropriate parameter selection.
Solution Approach 2:
The system dynamically selects which buffering parameters to apply based on the specific random access point type (CRA vs. BLA pictures) and whether decodable leading pictures are present. This dynamic adaptation allows the buffering mechanism to optimize performance for different playback scenarios, resolving the contradiction between reduced latency and reliable buffer management.
2Adaptability or versatility
If multiple buffering parameters are signaled, then playback can be optimized for different random access scenarios, but message complexity and processing overhead increase
Solution Approach 1:
The patent segments the buffering parameter information into distinct fields within the SEI message, with each field corresponding to a specific random access scenario. The initial CPB removal delay parameter is used for standard cases, while initial alternative CPB removal delay and offset parameters are used specifically for BLA pictures with decodable leading pictures. This segmentation allows versatile optimization without requiring the entire parameter set in every message.
Solution Approach 2:
The SEI message structure is designed to be universal, accommodating multiple types of random access points (CRA and BLA pictures) and different scenarios (with or without decodable leading pictures) through a unified parameter signaling mechanism. This multi-functionality enables the system to handle diverse playback optimization needs while maintaining a consistent message format and processing approach.
Data Source
AI summary
An electronic device for sending a message is described. The electronic device includes a processor and instructions stored in memory that is in electronic communication with the processor. The electronic device determines whether a picture is a random access point (RAP) picture. The electronic device also determines whether the picture is associated with a broken link access (BLA) with decodable leading pictures (DLP) network access layer (NAL) unit type if the picture is a RAP picture. The electronic device further generates a message including a RAP coded picture buffer (CPB) parameter flag and an initial additional CPB removal delay parameter if the BLA with DLP NAL unit type is present. The electronic device additionally sends the message.