HEVC Trick Mode Access via Tier Framework Assistance
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Solution Overview
Problem
There is a need in High Efficiency Video Coding (HEVC) bitstreams to provide assistance information that supports trick mode functionalities such as fast forward, reverse, slow forward, slow reverse, frame stepping, and pause, particularly for applications like personal video recording (PVR), digital video recording (DVR), and video on demand (VOD), to enable efficient random access and playback manipulation.
Innovation Solution
The solution involves a video stream receive-and-process device that conveys and processes assistance information associated with HEVC bitstreams, using tier frameworks to signal picture interdependencies, allowing for the extraction of self-decodable sub-streams and disabling trick modes in specific segments, ensuring synchronization and efficient decoding, particularly by utilizing assistance information carried in the Adaptation Field of MPEG-2 transport packets and packetized elementary streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If assistance information is provided in HEVC bitstreams to support trick mode functionalities, then trick mode operations (fast forward, reverse, frame stepping) become enabled and efficient, but the bitstream structure and decoding process become more complex
Solution Approach 1:
The patent segments the video stream into accessible units marked by Access Unit Start (AUS) markers, allowing trick mode operations to access specific segments independently. This segmentation enables fast forward, reverse, and frame stepping by selecting and decoding only the necessary segments rather than processing the entire stream, thus enabling versatility while managing complexity through structured organization.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of assistance information and marker symbols within the bitstream that mediate between the video data and the playback control system. These intermediaries carry metadata about picture dependencies and access points, enabling the decoder to intelligently navigate and extract specific frames for trick mode operations without requiring fundamental changes to the core decoding architecture.
2Ease of operation
If random access is enabled for trick mode operations, then playback flexibility is improved, but channel change time increases
Solution Approach 1:
The patent applies preliminary action by pre-marking Access Unit Start (AUS) locations and embedding assistance information that describes picture dependencies and access points before actual trick mode operations are requested. This advance preparation allows the decoding system to quickly locate and jump to specific frames without performing time-consuming analysis during the actual transition, thereby reducing channel change time while maintaining playback flexibility.
Solution Approach 2:
The patent enables skipping by allowing the decoder to bypass unnecessary intermediate frames and directly access target frames marked by AUS markers. When trick mode operations are invoked, the system can rush through the bitstream by skipping non-essential data and jumping directly to the required access points, significantly reducing the time needed for channel changes and mode transitions.
3Productivity
If tier framework is used to signal picture interdependencies, then decoding efficiency is improved, but the complexity of processing assistance information increases
Solution Approach 1:
The patent applies local quality by organizing picture interdependency information into localized tiers and groups rather than requiring global analysis of the entire bitstream. Each tier contains specific metadata about picture dependencies relevant only to that local region, allowing the decoder to process assistance information in manageable chunks and apply decoding optimizations locally without overwhelming complexity in the overall processing architecture.
Data Source
AI summary
Assistance information related to a tier framework may describe signaling for extractable and decodable sub-sequences based on pictures interdependencies. This may allow a video application to efficiently select pictures when performing a given trick mode.