Overview
ISO/IEC 23009-5:2017/Amd 1:2020 is an international standard amendment focused on enhancing Server and Network Assisted Dynamic Adaptive Streaming over HTTP (DASH), commonly referred to as SAND. This amendment introduces improvements to SAND messages, which play a critical role in enabling efficient and adaptive media streaming by facilitating better communication between servers, network components, and DASH clients. The update strengthens the capabilities of network-assisted streaming to optimize bandwidth allocation and streaming quality in dynamic network environments.
Key Topics
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Improvements on SAND Messages
The amendment revises the structure and parameters of SAND messages to better support server and network communication with DASH clients. Key enhancements include updated message formats that improve clarity and interoperability:
- Introduction of the AnticipatedRequests parameter for prioritizing upcoming client requests.
- Clarification on the use of
supportedMessage and messageSetUri attributes, allowing clients to declare support for multiple message types simultaneously.
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Message Structure Enhancements
Adjustments to XML schema definitions for SAND messages, such as the DaneCapabilitiesType and SANDMessageType, provide a more flexible and extensible message structure. For example:
messageId attribute handling is modified to be optional, enhancing message validation.- The addition of complex types to define message capabilities improves precision in client-server negotiation.
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Bandwidth Allocation Algorithms
The amendment outlines refined algorithms for bandwidth allocation using the allocate_at_most() function. This allows network-assisted DASH implementations to:
- Assign the minimum bandwidth necessary for a client's highest feasible operation point.
- Potentially allocate additional bandwidth up to the available limit for improved streaming performance.
- Empower network elements to dynamically optimize resource distribution based on current network conditions.
Applications
ISO/IEC 23009-5:2017/Amd 1:2020 is essential for organizations developing or implementing adaptive streaming solutions within telecommunications, content delivery networks (CDNs), and multimedia service providers. Practical applications include:
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Adaptive Video Streaming Platforms
Enhancing video quality adaptation by leveraging server and network assistance, reducing buffering and improving user experience.
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Telecommunications Network Optimization
Enabling network operators to manage bandwidth distribution efficiently among multiple DASH clients to meet service level agreements (SLAs).
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Multimedia Content Delivery
Supporting scalable and efficient streaming of live and on-demand content over HTTP with dynamic adjustment to network variations.
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Standard-Compliant DASH Player Development
Assisting developers of DASH clients and players to implement compliant message handling and bandwidth adaptation for improved interoperability.
Related Standards
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ISO/IEC 23009 Series (DASH Standards)
Consists of multiple parts detailing adaptive streaming fundamentals, segmentation, and payload formats.
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ISO/IEC 23009-1
Defines the core components of Dynamic Adaptive Streaming over HTTP, providing the foundation for the SAND extensions.
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ISO/IEC 23009-2, -3, -4
Address other aspects of DASH streaming such as segment formats, server and network assistance, and session control.
Adhering to ISO/IEC 23009-5:2017/Amd 1:2020 ensures compliance with globally recognized best practices for adaptive streaming, enabling high-quality multimedia delivery optimized for modern network infrastructures.
Keywords: ISO/IEC 23009-5 amendment, dynamic adaptive streaming, DASH, server and network assisted DASH (SAND), SAND messages, bandwidth allocation, HTTP streaming, multimedia streaming standards, network optimization, adaptive video streaming.