@iimrd/dvbcss-browser

Browser-specific transports for the DVB-CSS synchronisation protocols. Provides MessagePort-based adaptors for use in browser environments and Trusted Web Activities (TWAs), alongside re-exported WebSocket-based protocol implementations from @iimrd/dvbcss-node.

This package is part of the @iimrd/dvbcss-protocols monorepo.

Installation

pnpm add @iimrd/dvbcss-browser @iimrd/dvbcss-clocks

Feature support

| Feature | Transport | |---|---| | CII client | WebSocket, MessagePort | | TS client | WebSocket, MessagePort | | WC client | WebSocket (JSON), MessagePort (binary) |

API overview

This package re-exports everything from @iimrd/dvbcss-node except UdpAdaptor (UDP is not available in browsers), plus the following browser-specific additions:

| Export | Description | |---|---| | MessagePortAdaptor | SocketAdaptor implementation for MessagePort (e.g. MessageChannel or TWA bridge). | | createBinaryMessagePortWCClient | Creates a Wall Clock client over a MessagePort using binary encoding. | | createMessagePortCIIClient | Creates a CII client over a MessagePort with JSON encoding. Returns an AdaptorWrapper. | | createMessagePortTSClient | Creates a TS client over a MessagePort with JSON encoding. |

Quick example

Wall Clock client over MessagePort

import { DateNowClock, CorrelatedClock } from "@iimrd/dvbcss-clocks";
import { createBinaryMessagePortWCClient } from "@iimrd/dvbcss-browser";

const root = new DateNowClock();
const wallClock = new CorrelatedClock(root);

// messagePort could come from a MessageChannel, a TWA bridge, etc.
const wcClient = createBinaryMessagePortWCClient(messagePort, wallClock);

CII client over MessagePort

import { createMessagePortCIIClient } from "@iimrd/dvbcss-browser";

const ciiClient = createMessagePortCIIClient(messagePort);

ciiClient.on("change", (cii, changemask) => {
  console.log("CII state changed:", cii);
});

TS client over MessagePort

import { CorrelatedClock } from "@iimrd/dvbcss-clocks";
import { createMessagePortTSClient } from "@iimrd/dvbcss-browser";

// wallClock should already be synchronised via a WC client
const syncTLClock = new CorrelatedClock(wallClock);

const tsClient = createMessagePortTSClient(messagePort, syncTLClock, {
  contentIdStem: "dvb://",
  timelineSelector: "urn:dvb:css:timeline:pts",
});

WebSocket-based clients (also available)

All WebSocket-based factories from @iimrd/dvbcss-node are re-exported, so you can also use them directly:

import { createJsonWebSocketClient, createCIIClient, createTSClient } from "@iimrd/dvbcss-browser";

Licence and Authors

All code and documentation is licensed by the original author and contributors under the Apache License v2.0:

• British Broadcasting Corporation (original author)
• Institut für Rundfunktechnik
• British Telecommunications (BT) PLC

See the AUTHORS file for a full list of individuals and organisations that have contributed to this code.