Video Bitstream Conformance Signaling for Multi-Profile Decoding
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Solution Overview
Problem
Current video coding standards face challenges in efficiently representing compatibility with multiple profiles or sub-profiles, especially with the anticipated large number of user-defined profiles and sub-profiles in emerging standards like VVC, which requires a more practical mechanism than bitmasks for indicating compatibility.
Innovation Solution
The introduction of a syntax structure that allows for the representation of multiple conformance points, such as profiles and sub-profiles, using longer identifiers like T.35 strings, UUIDs, or URIs, which can be encoded in a bitstream as a list, enabling a larger numbering space and flexible representation of compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bitmasks are used to indicate compatibility with multiple profiles, then compatibility information can be represented, but the mechanism becomes impractical when the number of profiles and sub-profiles becomes very large
Solution Approach 1:
The patent segments the compatibility indication mechanism into two parts: a bitmask for indicating support for major profiles, and a list of conformance point identifiers for specifying exact compatibility. This segmentation allows the system to handle both the broad profile compatibility and specific sub-profile variations efficiently, avoiding the need for an impractically large bitmask while maintaining comprehensive compatibility information.
Solution Approach 2:
The patent transitions from a one-dimensional bitmask approach to a two-dimensional representation by introducing a list of conformance point identifiers alongside the bitmask. This additional dimension allows the system to specify exact profile and sub-profile combinations without requiring an exponentially larger bitmask, thus resolving the scalability issue while maintaining compatibility representation capability.
2Adaptability or versatility
If a large number of user-defined profiles and sub-profiles are supported, then the numbering space must be expanded, but bitmask representation becomes impractical
Solution Approach 1:
The patent segments the profile identification system into major profiles (indicated by bitmask) and specific conformance points (indicated by identifiers in a list). This segmentation allows the system to support a large number of user-defined profiles and sub-profiles without requiring an impractically large bitmask, as only the specific conformance points need to be explicitly listed rather than representing all possible combinations.
Solution Approach 2:
The patent uses conformance point identifiers (such as T.35 strings, UUIDs, or URIs) that can reference previously defined profiles and sub-profiles. This copying mechanism allows the bitstream to indicate compatibility with multiple conformance points without duplicating the full profile definitions, thus supporting a large numbering space while keeping the bitstream size manageable.
3Reliability
If multiple encoders are used to serve different ecosystems, then decoding compatibility is ensured, but compression complexity and processing requirements increase
Solution Approach 1:
The patent implements a universal compatibility indication mechanism that allows a single encoder to produce bitstreams compatible with multiple profiles and sub-profiles. By using the combination of bitmask and conformance point identifier list, one encoder can serve multiple ecosystems simultaneously, eliminating the need for multiple specialized encoders while maintaining decoding compatibility across different platforms.
Solution Approach 2:
The patent changes the parameters used to indicate profile compatibility from a simple bitmask to a more flexible structure combining bitmask and conformance point identifiers. This parameter change allows a single encoder to efficiently indicate support for multiple profiles and sub-profiles, reducing the need for multiple encoders while ensuring decoding compatibility across different ecosystems.
Data Source
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AI summary
A method and apparatus for media decoding by a decoder include decoding a first indication indicative of a first conformance point of a coded video sequence. A second indication indicative of a second conformance point of the coded video sequence is decoded. It is determined whether the coded video sequence is decodable by the decoder based on at least one of the first indication and the second indication. The coded video sequence is selectively decoded based on determining whether the decoded video sequence is decodable by the decoder.