Segment Encryption Signaling for Adaptive Streaming
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Solution Overview
Problem
Conventional segment encryption protection schemes in adaptive streaming, such as MPEG-DASH, are inflexible and inefficient, often requiring multiple CryptoPeriod elements for alternating segment encryption, increasing MPD size and startup time, and do not support late binding of initialization vectors or multiple encryption algorithms.
Innovation Solution
The introduction of flexible signaling mechanisms, including the @segmentEncryptionFlag and @segmentEncryptionSignaling attributes, allows for efficient and compact signaling of encrypted segments, supporting late binding of initialization vectors and multiple encryption algorithms, enabling more flexible content protection in adaptive streaming environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional segment encryption schemes use multiple CryptoPeriod elements for alternating segment encryption, then content protection is achieved, but MPD size increases and startup time increases
Solution Approach 1:
The patent segments the encryption configuration into two distinct parts: (1) a compact segment encryption signaling structure in the MPD that identifies encrypted segments using efficient data structures, and (2) separate initialization vector (IV) binding mechanisms that are resolved later during playback. This segmentation allows the MPD to remain small while enabling comprehensive encryption control.
Solution Approach 2:
The patent performs preliminary identification of encrypted segments in the MPD using compact signaling, but delays the binding of initialization vectors until later during segment retrieval or playback. This preliminary action separates the structural configuration from the cryptographic key binding, reducing initial MPD size while maintaining security.
2Reliability
If conventional segment encryption schemes use multiple CryptoPeriod elements, then alternating segment encryption is achieved, but MPD size increases
Solution Approach 1:
The patent divides the encryption signaling into two independent components: (1) segment-level encryption identification using compact data structures in the MPD, and (2) separate IV binding information that can be resolved later. This segmentation eliminates the need for repetitive CryptoPeriod elements while maintaining precise encryption control.
Solution Approach 2:
The patent transitions from a time-based encryption model (multiple CryptoPeriod elements covering different time intervals) to a segment-based encryption model where each encrypted segment is independently identified using efficient data structures. This dimensional change from temporal to segment-level organization reduces MPD complexity and size.
3Device complexity
If conventional schemes use a single algorithm approach for stream encoding, then implementation simplicity is maintained, but content from different sources cannot be merged
Solution Approach 1:
The patent creates a universal segment encryption signaling framework that can accommodate multiple encryption algorithms and content sources. The signaling structure is algorithm-agnostic, allowing different encryption schemes to be applied to different segments from different sources while maintaining a unified representation in the MPD.
Solution Approach 2:
The patent enables dynamic parameter changes in encryption algorithms by allowing each segment or segment group to specify its own encryption parameters independently. This flexibility allows content from different sources with different encryption schemes to be merged into a single adaptive streaming manifest without requiring a single fixed algorithm approach.
Data Source
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AI summary
An apparatus for decoding a media stream, wherein the apparatus comprises a memory module, a processor module coupled to the memory module, wherein the memory module contains instructions that when executed by the processor cause the apparatus to perform the following: receive a media stream comprising a segment signaling information and a plurality of segments, wherein the plurality of segments comprises encoded and unencoded segments, wherein the segment signaling information comprises identification of at least two segment groups each comprising at least one segment, identify at least one segment group using the segment signaling information in the media stream, identify at least one segment decoding algorithm for the at least one segment group, identify at least one decoding key for the at least segment group, and decode each encoded segment within the at least segment group using the at least segment decoding algorithm and the at least one decoding key.