The EME Call and Event Logger Extension

The EME Logger extension logs all Encrypted Media Extension (EME) calls and Events. The log can be viewed in the javascript console, a separate browser page or a downloaded file.

EME Specification

Just want to try it out? Install the EME Logger from Chrome Web Store.

EME Formatters

Formatters can be used with the EME Logger extension. Formatters are separate extensions that provide a class for key system-specific custom formatting of data from the calls and events. Formatters should use \n for line breaks. This extension will convert these to <br> and preserve spaces when generating HTML.

To register a message formatter:

1. Write a class that implements isKeySystemSupported(keySystem) and the relevant logging methods.
2. Append an instance of the class to document.emeFormatters.

For example:

function SomeSystemFormatter() {
  this.isKeySystemSupported = function (keySystem) {
    return keySystem == "com.example.somesystem";
  }

  // Unprefixed logging methods.
  this.formatUpdateCall = function (response) {
    return "SomeSystemFormatter saw an UpdateCall with: " + response;
  }
  this.formatmessage = function (message) {
    return "SomeSystemFormatter saw a MessageEvent with: " + message;
  }

  // Prefixed logging methods.
  this.formatwebkitkeymessage = function (message) {
    return "SomeSystemFormatter saw a KeyMessageEvent with: " + message;
  }
  this.formatAddKeyCall = function (key) {
    return "SomeSystemFormatter saw an AddKeyCall with: " + key;
  }
}

if (!document.emeFormatters)
  document.emeFormatters = [];
document.emeFormatters.push(new SomeSystemFormatter);