Status of implementation

Here, we address questions about changes to the PeerConnection API and other topics that developers have been asking about recently.

  1. Can the microphone input from GetUserMedia be used to pipe it to the <audio> for local playback?
    1. No, the <audio> tag does not support MediaStreams yet but it is currently being worked on.

PeerConnection API Status
  1. Can you summarize the evolution of the PeerConnection API changes? There have been many changes. Here is a little history and background and the latest (Oct 1st 2012, Chrome M23).
    1. The first implementation of PeerConnection API was changed to webkitDeprecatedPeerConnection and the latest implementation webkitPeerConnection00  was introduced. This reason for this is detailed in a blog post but, in short, we switched from a ROAP based signalling mechanism to JSEP.
    2. webkitDeprecatedPeerConnection was removed and replaced by webkitPeerConnection00.
    3. The W3C made further significant changes, including a naming convention change. Chrome M23 introduces RTCPeerConnection. Since this is what will be shipping in Chrome, we have moved webkitPeerConnection00 behind a flag. Here is what we have implemented in Chrome:

with these two APIs:
    void        createAnswer (RTCSessionDescriptionCallback successCallback, optional RTCPeerConnectionErrorCallback? failureCallback = null, optional MediaConstraints constraints = null);
    void        updateIce (optional RTCConfiguration? configuration = null, optional MediaConstraints? constraints = null);
instead of :
    void        createAnswer (RTCSessionDescription offer, RTCSessionDescriptionCallback successCallback, optional RTCPeerConnectionErrorCallback? failure Callback = null, optional MediaConstraints constraints = null, optional boolean createProvisionalAnswer = false);
    void        updateIce (optional RTCConfiguration? configuration = null, optional MediaConstraints? constraints = null, optional boolean restart = false);

Data Channels
  1. What is the status of the Data Channel API?
    1. The Data Channel API is not implemented and its implementation is being discussed in the standards committee. We will begin to focus on it as soon as we stabilize PeerConnection. Please refer to our latest presentation from Google I/O that will give one a good idea of what the Data Channel API will look like.

  1. TURN support is being introduced in Chrome 24. Please run Chrome Canary or Dev Channel to try it out.
  1. OPUS audio codec support is being introduced in Chrome 24. Please run Chrome Canary or Dev Channel to try it out.

  1. When will ICE be fully RFC 5245 compliant and be enabled in PeerConnection?
    1. Chrome M23 ships with a first version of the newly compliant API. Join our discuss list to help iron out issues.


  1. How do I mute an outgoing track?
    1. Set track.enabled to false, not yet wired up but there is a tracking bug for it
  2. How do I stop sending RTP packets?
    1. Set a=inactive in your SDP, and update your local description


  1. What is the status of the recording functionality?
    1. Recording does not have a stable specification yet and our current focus is on PeerConnection.

DTMF support

  1. What is the the current status of DTMF support?
    1. We are nearly complete with the native implementation of DTMF as specified except for:
      1. The character “,” indicates a delay of 2 seconds before processing the next character in the tones parameter
      2. If insertDTMF is called on the same object while an existing task for this object is generate DTMF is still running, the previous task is canceled
After this is complete, we hope to wire this up in WebKit.