wive

Third-party Encrypted Media Extensions (EME) implementation with Widevine custom client support

Usage

The following is a minimal example of using wive to get a License for Bitmovin's Art of Motion Demo. This example similar to example from EME.

import { requestMediaKeySystemAccess, Client } from 'wive';
import { readFile } from 'node:fs/promises';

const licenseUrl = 'https://cwip-shaka-proxy.appspot.com/no_auth';
const pssh =
  'AAAAW3Bzc2gAAAAA7e+LqXnWSs6jyCfc1R0h7QAAADsIARIQ62dqu8s0Xpa7z2FmMPGj2hoNd2lkZXZpbmVfdGVzdCIQZmtqM2xqYVNkZmFsa3IzaioCSEQyAA==';

const handleMessageResponse = (keySession, response) => {
  keySession.update(response);
};

const sendMessage = async (type, message, keySession) => {
  const response = await fetch(licenseUrl, { body: message, method: 'POST' });
  const data = await response.arrayBuffer();
  handleMessageResponse(keySession, data);
};

const handleMessage = (event) => {
  sendMessage(event.messageType, event.message, event.target);
};

const handleKeyStatusesChange = (event) => {
  const keySession = event.target;
  const keys = Array.from(keySession.keyStatuses.keys());
  for (const key of keys) {
    const [id, value] = key.toString().split(':');
    console.log(`KID:KEY -> ${id}:${value}`);
  }
};

(async () => {
  const clientId = await readFile('device_client_id_blob');
  const clientKey = await readFile('device_private_key');
  const client = new Client(clientId);
  await client.importKey(clientKey);

  const initDataType = 'cenc';
  const initData = Buffer.from(pssh, 'base64');

  const keySystemAccess = await requestMediaKeySystemAccess('com.widevine.alpha', [{ client }]);
  const mediaKeys = await keySystemAccess.createMediaKeys();
  const keySession = mediaKeys.createSession();
  keySession.addEventListener('message', handleMessage, false);
  keySession.addEventListener('keystatuseschange', handleKeyStatusesChange, false);
  await keySession.generateRequest(initDataType, initData);
})();

There are some differences from the native EME implementation:

1. You must import your Widevine client to obtain a license.
2. In the keyStatuses field, Map's key is not just the key ID (like in EME), but also the key itself for decrypting the content. For example, if key ID in HEX is 35e7eff366b24121a261832f3368146f and content key itself is f01471043a064e039a602346845b690f then Map's key will be 35e7eff366b24121a261832f3368146f:f01471043a064e039a602346845b690f (but as binary with Buffer type) instead of just 35e7eff366b24121a261832f3368146f.