Architecture

Amazon Vinyl is an HTML5 playback engine designed for high-performance streaming of DASH and HLS content. The architecture follows a modular design with clear separation of concerns, enabling extensibility through dependency injection.

Core Components

                            +-------------+
                            | VinylPlayer |
                            +------+------+
                                   |
                    +--------------+-----------------+
                    |              |                 |
                    v              v                 v
            +---------------+ +----------+   +----------------+
            |TrackController| |Playback  |   |DrmController   |
            |               | |Controller|   |                |
            +-------+-------+ +----+-----+   +-------+--------+
                    |              |                 |
                    v              v                 v
            +---------------+ +-----------+   +-----------+
            | Track         | | Media     |   | EME       |
            | (Dash/Hls)    | | Element   |   | (Browser) |
            |               | | (Browser) |   |           |
            +-------+-------+ +-----------+   +-----------+
                    |   |
                    |   +----------------------+
                    v                          v
            +-------------------+     +----------------+
            |BufferingController|     |SourceBuffer    |
            |                   |     |Controller      |
            +----------+--------+     +--------+-------+
                       |                       |
                       v                       v
            +-------------------+     +----------------+
            |SegmentController  |     |SourceBuffer    |
            |                   |     |(Browser)       |
            +----------+--------+     +----------------+
                       |
                       v
            +-------------------+
            |SegmentProvider    |
            |                   |
            +-------------------+

Component Ownership

VinylPlayer

Main entry point that orchestrates all streaming components and provides the public API.

• Owns: TrackController, PlaybackController, DrmController
• Dependencies: AutoResetController, QualitySelector
• Role: Main orchestrator and public API
• Responsibilities:
  • Coordinate component lifecycle
  • Expose unified playback interface
  • Handle global error management

TrackController

Manages the lifecycle of streaming tracks and maintains a playback queue.

• Owns: Track instances (e.g. SourceTrack/DashTrack/HlsTrack), Track cache
• Dependencies: TrackFactory
• Role: Track lifecycle and queue management
• Responsibilities:
  • Validate and create tracks
  • Manage playback queue
  • Handle track transitions

PlaybackController

Controls the HTML5 media element and manages playback state transitions.

• Owns: HTML5 Media Element
• Dependencies: PlaybackSource
• Role: Media element control and state management
• Responsibilities:
  • Control play/pause/seek operations
  • Monitor playback state changes
  • Handle media element events

DrmController

Handles encrypted content by managing DRM licenses and key exchanges.

• Owns: License sessions, Key management
• Dependencies: EME APIs, License servers
• Role: Content decryption and license management
• Responsibilities:
  • Handle DRM initialization
  • Manage license requests
  • Process key messages

Track (DashTrack/HlsTrack)

Protocol-specific implementation that coordinates manifest parsing and media streaming.

• Owns: ManifestController, BufferingController, SegmentController
• Dependencies: ManifestProvider, RepresentationProvider
• Role: Protocol-specific streaming logic
• Responsibilities:
  • Coordinate sub-controllers for manifest resolution and parsing, segment fetching, buffering, and encryption
  • Handle protocol-specific features
  • Handle track lifecycle
  • Provide streaming quality and prefetch status and updates

BufferingController

Manages the MediaSource buffer by coordinating segment appending and buffer health.

• Owns: Segment append queue, Buffer state
• Dependencies: SourceBufferController, SegmentController, PlaybackController
• Role: Media source buffer management
• Responsibilities:
  • Coordinate segment appending
  • Handle buffer quotas

SegmentController

Manages segment caching and prioritization while coordinating with providers for media locations.

• Owns: Segment cache, Priority queue
• Dependencies: SegmentProvider, QualitySelector
• Role: Segment caching and prioritization
• Responsibilities:
  • Prioritize segment requests
  • Manage segment cache

SegmentProvider

Resolves media segment locations and handles the actual fetching of segment data.

• Owns: Network requests, Segment timeline
• Dependencies: ManifestController, NetworkQueue
• Role: Media segment resolution and fetching
• Responsibilities:
  • Resolve segment URLs from manifest
  • Fetch segment data over network
  • Handle segment-specific transformations

QualitySelector

Determines optimal playback quality based on network conditions.

• Owns: Quality selection algorithm
• Dependencies: NetworkMetrics, DeviceCapabilities, BufferHealth
• Role: Adaptive bitrate selection
• Responsibilities:
  • Monitor network performance
  • Select appropriate quality levels
  • Adapt to changing conditions

ManifestController

Parses and manages streaming manifests, handling updates and transformations.

• Owns: Manifest data, Parser instances
• Dependencies: ManifestProvider, ManifestTransformer
• Role: Manifest parsing and refresh management
• Responsibilities:
  • Load and parse streaming manifests (MPD/M3U8)
  • Handle manifest updates
  • Transform manifest data