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AAMP Architecture

Overview

This document provides an architectural overview of the Advanced Adaptive Media Player (AAMP). For comprehensive architectural details, design patterns, and module descriptions, refer to .github/instructions/aamp.instructions.md.

Core Components

Native Engine (C++)

  • Foundation: Built on GStreamer for low-level media handling
  • Optimization: Designed for performance, memory efficiency, and embedded constraints
  • Primary Use Case: Core playback engine for RDK-based devices

JavaScript Bindings (UVE)

  • Interface: Universal Video Engine (UVE) API provides JavaScript access to AAMP
  • Implementation: WebKit Injectedbundle on RDK platforms
  • Compatibility: Also available as API wrapper for non-RDK browsers

Key Architectural Principles

SOLID Design

  • Single Responsibility: Each module has one clear purpose
  • Open/Closed: Extend via interfaces, not by modifying core logic
  • Liskov Substitution: Subtypes are interchangeable
  • Interface Segregation: Small, specific interfaces
  • Dependency Inversion: Depend on abstractions

Modern C++ Patterns

  • RAII (Resource Acquisition Is Initialization) for all resources
  • Smart pointers (unique_ptr, shared_ptr) instead of raw pointers
  • Composition over inheritance
  • Low cyclomatic complexity

Video Streaming Focus

  • Low latency playback
  • Correct buffering behavior
  • Real-time performance guarantees
  • Minimal memory footprint

Module Organization

  • Fragment Collectors: HLS (fragmentcollector_hls.cpp), DASH (fragmentcollector_mpd.cpp), Progressive MP4
  • DRM Support: Clear Key, AES-128, PlayReady, Widevine
  • Buffering & ABR: Adaptive bitrate management and buffer control
  • Event Management: Event dispatching and listener coordination
  • Diagnostics: Profiling, telemetry, and logging

Threading & Concurrency

AAMP uses a scheduler-based approach with worker threads for asynchronous operations:

  • Fragment downloading happens on worker threads
  • Main playback synchronization on GStreamer thread
  • Thread-safe event handling through event manager

Configuration System

Configuration has priority order (lowest to highest):

  1. AAMP defaults in code
  2. Operator settings (RFC/ENV variables)
  3. Stream-provided settings
  4. Application settings
  5. Developer configuration (/opt/aamp.cfg, /opt/aampcfg.json)

See CONFIGURATION.md for detailed options.

Further Reading