p2p-media-loader-core v0.6.2

P2P Media Loader Core

Core functionality for P2P sharing of segmented media streams (i.e. HLS, MPEG-DASH) using WebRTC.

Useful links:

• P2P development, support & consulting
• Demo
• FAQ
• Overview
• Technical overview
• JS CDN
  • Core
  • Hls.js integration
  • Shaka integration

API

The library uses window.p2pml.core as a root namespace in Web browser for:

• HybridLoader - HTTP and P2P loader
• Events - Events emitted by HybridLoader
• Segment - Media stream segment
• version - API version

HybridLoader

HTTP and P2P loader.

HybridLoader.isSupported()

Returns true if WebRTC data channels API is supported by the browser. Read more here.

loader = new HybridLoader([settings])

Creates a new HybridLoader instance.

If settings is specified, then the default settings (shown below) will be overridden.

SegmentsStorage interface

interface SegmentsStorage {
    storeSegment(segment: Segment): Promise<void>;
    getSegmentsMap(masterSwarmId: string): Promise<Map<string, {segment: Segment}>>;
    getSegment(id: string, masterSwarmId: string): Promise<Segment | undefined>;
    clean(lockedSementsfilter?: (id: string) => boolean): Promise<boolean>;
    destroy(): Promise<void>;
}

loader.load(segments, streamSwarmId)

Creates new queue of segments to download. Aborts all http and peer connections for segments that are not in the new load and emits Events.SegmentAbort event for each aborted event.

Function args:

• segments - array of Segment class instances with populated url and priority field;
• streamSwarmId - current swarm;

loader.on(Events.SegmentLoaded, function (segment, peerId) {})

Emitted when segment have been downloaded.

Listener args:

• segment - instance of Segment class with populated url and data fields;
• peerId - Id of the peer the segment was downloaded from; undefined for HTTP method;

loader.on(Events.SegmentError, function (segment, error, peerId) {})

Emitted when an error occurred while loading the segment.

Listener args:

• segment - url of the segment;
• error - error details;
• peerId - Id of the peer the error occured with; undefined for HTTP method;

loader.on(Events.SegmentAbort, function (segment) {})

Emitted for each segment that does not hit into a new segments queue when the load method is called.

Listener args:

• segment - aborted segment;

loader.on(Events.PeerConnect, function (peer) {})

Emitted when a peer is connected.

Listener args:

• peer - peer object with populated id and remoteAddress fields;

loader.on(Events.PeerClose, function (peerId) {})

Emitted when a peer is disconnected.

Listener args:

• peerId - Id of the disconnected peer;

loader.on(Events.PieceBytesDownloaded, function (method, bytes, peerId) {})

Emitted when a segment piece downloaded.

Listener args:

• method - downloading method, possible values: http, p2p;
• bytes - amount of bytes downloaded;
• peerId - Id of the peer these bytes downloaded from; undefined for HTTP method;

loader.on(Events.PieceBytesUploaded, function (method, bytes) {})

Emitted when a segment piece uploaded.

Listener args:

• method - uploading method, possible values: p2p;
• bytes - amount of bytes uploaded;
• peerId - Id of the peer these bytes uploaded to; undefined for HTTP method;

loader.getSettings()

Returns loader instance settings.

loader.getDetails()

Returns loader instance details.

loader.getSegment(id)

Returns a segment from loader cache or undefined if the segment is not available.

Function args:

• id - Id of the segment;

loader.destroy()

Destroys loader: abort all connections (http, tcp, peer), clears cached segments.

Events

Events that are emitted by HybridLoader.

• SegmentLoaded
• SegmentError
• SegmentAbort
• PeerConnect
• PeerClose
• PieceBytesDownloaded
• PieceBytesUploaded

Segment

Media stream segment.

Instance contains:

• id
  • a String
  • unique identifier of the segment across peers
  • can be equal to URL if it is the same for all peers
• url + a String + URL of the segment masterSwarmId + a String + segment's master swarm ID masterManifestUri + a String + segment's master manifest URI streamId + a String or undefined + segment's stream ID sequence + a String + segment's sequence ID
• range or undefined
  • a String
  • must be valid HTTP Range header value or undefined
• priority
  • a non-negative integer Number
  • the lower value - the higher priority
  • default is 0
• data
  • an ArrayBuffer or undefined
  • available only when segment is fully loaded; subscribe to SegmentLoaded event for this very moment
• downloadSpeed or undefined
  • a non-negative integer Number
  • download speed in bytes per millisecond or 0
• requestUrl
  • a String or undefined
  • Request URL of the segment
• responseUrl
  • a String or undefined
  • Response URL of the segment

Usage Example

var loader = new p2pml.core.HybridLoader();

loader.on(p2pml.core.Events.SegmentLoaded, function (segment) {
    console.log("Loading finished, bytes:", segment.data.byteLength);
});

loader.on(p2pml.core.Events.SegmentError, function (segment, error) {
    console.log("Loading failed", segment, error);
});

loader.load([
    new p2pml.core.Segment("segment-1", "//url/to/segment/1", undefined, 0),
    new p2pml.core.Segment("segment-2", "//url/to/segment/2", undefined, 1),
    new p2pml.core.Segment("segment-3", "//url/to/segment/3", undefined, 2)
], "swarm-1");