All posts tagged Q&A

Pion seemingly came out of nowhere to become one of the biggest and most active WebRTC communities. Pion is a Go-based set of WebRTC projects. Golang is an interesting language, but it is not among the most popular programming languages out there, so what is so special about Pion? Why are there so many developers involved in this project? 

To learn more about this project and how it came to be among the most active WebRTC organizations, I interviewed its founder – Sean Dubois. We discuss Sean’s background and how be got started in RTC, so see the interview for his background.  I really wanted to understand why he decided to build a new WebRTC project and why he continues to spend so much of his free time on it. ...  Continue reading

Interview with WebRTC standards co-chair and author, Bernard Aboba. We cover the current status of WebRTC and where it is headed including WebRTC-NV, Simulcast, SVC, AV1, WebTransport, WebCodecs, ML and more.

While Windows may no longer be the default platform it was a decade ago it still has a huge and active community. More than 400 million devices support Windows 10 and there are many millions of .NET and Visual Studio users out there. In fact, I made my first WebRTC application in .NET using XSockets years ago.

In addition to the couple 3rd party WebRTC libraries for WebRTC, Edge & Skype support for WebRTC/ORTC, Microsoft’s has had a few other less known and non-public WebRTC projects in the works.  Last week they publicly launched WebRTC for Universal Windows Platform (UWP), providing WebRTC support for another huge chunk of the world’s developers.

I asked, James Cadd, Microsoft’s Program Manager in the Windows Developer Platform Group in charge of the project to share some details.


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Two weeks ago Microsoft’s Bernard Aboba (and former webrtcHack’s interviewee) gave an update on Edge’s ORTC and WebRTC at the Microsoft Build conference. He covered some big topics including VP8 and WebRTC 1.0 support. You can see the update video at the link above or read the follow-up post for details. Then last week Microsoft announced plug-in free Skype on the Edge browser.

I had some questions; Fippo had some questions; so we asked Bernard if he could publicly respond here. It turned out Bernard and his teammate on the Edge Browser team, Shijun Sun, were building a running list of questions they wanted to address too. Here it is.

{“editor”, “chad hart“}


Since we cover a lot here, below is a clickable table of contents in case you want to jump to a specific item:

Feature support

Interpreting the Edge Platform Status website

Q: How do I interpret the Edge Platform Status website (e.g. meaning of “in preview”, “in development”, “under consideration”)

A: Here are some guidelines:

  1. Under Consideration means on backlog for implementation in a future release. Priorities have the following explanations:
    • Low — We are still evaluating this technology. There may be significant spec stabilization, foundational work, or additional community input required before we can begin development.
    • Medium — Development is likely for a future release.
    • High — We intend to begin development soon.
  2. In Development means we have developers writing code actively on the feature.
  3. In Preview means available in latest Windows Insider build.

Note that you can vote for features that are “under consideration”!

If you have additional questions on our web platform, you can first check out our FAQ page.  Please send us feedback if you could not find answers to your questions there.

Stream & Port handling

Multiple Streams & Unified Plan

Q: The iswebrtready says Edge does not support multiple streams.  Do you support this in ORTC?  Will you support it in WebRTC 1.0?

A: Edge ORTC enables multiple streams to be carried over a single DtlsTransport.  However, the WebRTC 1.0 work item in development does not include support for multiple streams within PeerConnection, via “unified plan”.


Q: Does Edge support A/V multiplexing?  RTP/RTCP multiplexing?

A: Edge supports both A/V multiplexing and RTP/RTCP multiplexing.  RTP/RTCP multiplexing is required by the DtlsTransport, but RTP/RTCP non-mux is supported for use with the SrtpSdesTransport.


Q: What is the status of the WebRTC data channel?

A: The WebRTC data channel is currently listed as under consideration with a low priority on the Edge Platform Status site.

As part of a potential WebRTC data channel work item, the interaction of data channel congestion control with A/V congestion control needs to be considered. The current data channel implementations in Skype and Skype for Business were based on unified congestion control handling for both A/V and data,  

taking into account both delay and packet loss ...  Continue reading

If you are new to WebRTC then you have missed out on years of drama in the standards bodies over various issues like SDP and codecs. These standards dictate what vendors must implement so they ultimately dictate the industry roadmap.  To get a deep perspective and appreciation of the issues, we like to ask Dan Burnett, W3C editor to comment on where we are at with the standardization process. I caught up with Dan at this year’s IIT Real Time Communications Conference and had the more detailed Q&A with him shortly thereafter.

We asked Dan to comment on recent spec changes, ORTC, the next version of WebRTC, codecs, Apple, when the 1.0 spec might ever be finalized, and a whole lot more.

{“editor”, “chad hart“}


Want to keep up on our latest posts? Please click here to subscribe to our mailing list if you have not already. We only email post updates. You can also follow us on twitter at @webrtcHacks for blog updates.

We have been waiting a long time for Microsoft to add WebRTC to its browser portfolio. That day finally came last month when Microsoft announced its new Windows 10 Edge browser had ORTC. This certainly does not immediately address the Internet Explorer population and ORTC is still new to many (which is why we cover it often). On the positive side, interoperability between Edge, Chrome, and Firefox on the audio side was proven within days by multiple parties. Much of ORTC is finding its way into the WebRTC 1.0 specification and browser implementations. ...  Continue reading

Atlassian’s HipChat acquired BlueJimp, the company behind the Jitsi open source project. Other than for positive motivation, why should WebRTC developers care? Well, Jitsi had its Jitsi Video Bridge (JVB) which was one of the few open source Selective Forwarding Units (SFU) projects out there. Jitsi’s founder and past webrtcHacks guest author, Emil Ivov, was a major advocate for this architecture in both the standards bodies and in the public. As we have covered in the past, SFU’s are an effective way to add multiparty video to WebRTC. Beyond this one component, Jitsi was also a popular open source project for its VoIP client, XMPP components, and much more. ...  Continue reading

The world of browsers and how they work is both complex and fascinating. For those that are new to the browser engine landscape, Google, Apple, and many others collaborated on an open source web rendering engine for many years known as WebKit.  WebKit has active community with many less well known browsers that use it, so the WebKit community was shocked when Google announced they would fork WebKit into a new engine for Chrome called Blink.

Emphasis for implementing WebRTC shifted with Google into Blink at the expense of WebKit. To date, Apple has not given any indications it was going to add  WebRTC into WebKit (see this post for an idea on nudging them). This is not good for the eclectic WebKit development community that would like to start working with WebRTC or those hoping for WebRTC support in Apple’s browsers.

Then an interesting project by Ericsson, Temasys, and Igalia was announced –  webrtcinwebkit. As the name implies, the goal of this project was to put WebRTC in WebKit, by themselves. Many questions come to mind, but the most important may be is this a worthwhile effort and one that other WebRTC developers should be involved in?

I asked webrtcinwebkit contributors Alex Gouaillard and Stefan Håkansson to give some more background and help answer who should care about this project and why they are working on this.

{“intro-by”, “chad hart“}




webrtcHacks: For those who are not familiar, can you describe the webrtcinwebkit project?

Alex:  webrtcinwebkit is a project aiming at bringing WebRTC support in WebKit which is the foundation of a lot of web browsers like Safari and web browsing frameworks like WebView used extensively in Mobile applications.

webrtcHacks: How did this come together? Who are the major contributors to this project?

Alex:  in 2014, Ericsson had an initial implementation to flesh out and was thinking about open sourcing the underlying engine now known as OpenWebRTC. Igalia’s Philippe Normand had been trying to integrate WebRTC in WebKitgtk+ using Ericsson’s 2011 code base for some time, Temasys was trying to find a way to enable WebRTC in iOS and remove the need for a plugin in desktop Safari. At a W3C meeting in Santa Clara in November 2014, a discussion happened with an Apple employee that make the parties believe that there was a way. The project was born.

webrtcHacks: Why do you think Apple has not implemented WebRTC already? How will webrtcinwebkit change that?

Alex:  Those who know can’t talk and those who talk likely don’t know.

Our answer is: we don’t know for sure.

webrtcHacks: How much of this project is about Apple vs. other WebKit users?

Alex:  Not at all about Apple. We’re working on adding WebRTC API’s to WebKit, and to back it with OpenWebRTC for the WebKitgtk+ port. To what extent other ports make use of the WebRTC API’s is up to them, but of course we hope they will use them.

webrtcHacks: was there a lot of WebRTC in WebKit already from before Google forked blink?

Stefan:  Yes, there was quite a bit of WebRTC in there, contributed by Ericsson, Google, Igalia and others. Some parts can be re-used, but largely the standard has evolved so much that we had to start over.


webrtcHacks: Can you comment on how your perspective of how Google’s forking of webkit has impacted the webkit community? Isn’t everyone just moving to blink now?

Stefan:  Just looking at the revision history of the WebKit source code will immediately show that the WebKit project is very much alive.

webrtcHacks: Is there value in webrtcinwebkit for other developers even if Apple ignores this?

Alex:  the WebKit community itself is pretty big, and again as far as mobile and embedded devices are concerned, this is the main way of handling web pages. Whether Apple adopt the changes or not, this is good news for many people.

Stefan: I agree fully. I would also like to add the value for the WebRTC community and the standardization effort of a second, independent implementation, as the initial back end used will be OpenWebRTC. The current WebRTC implementations in Chrome, Firefox and Opera all to a large extent use the same webrtc.org backend so we think it is a point in using OpenWebRTC as the backend as it gives a second, truly independent, implementation of the standard.

webrtcHacks: How much effort is  going into this project? Is it staffed adequately for success?

Alex:  Everybody is working on separate projects, so depending for example if you count people working on OpenWebRTC as being part of this project or not, the count will change. There are roughly the following Full-time-equivalent (FTE) staff:

  • 4  at Ericsson
  • 2 Ericsson contractors
  • 2 Temasys
  • 1 Igalia

Not all FTE are equal contributors though and the main technical leaders (for WebKit) are with Ericsson and Igalia.

webrtcHacks: How long will it take to complete?

Alex:  We have a version that includes getUserMedia already working a demoable in a separate fork. Ericsson is polishing the PeerConnection, while Temasys is handling Datachannel. It then takes a little bit of time to submit patches to upstream WebKit, so the nightly version of WebKit is still behind. OpenWebRTC and webrtc in WebKit is based on a very recent version of GStreamer, and updating that component in WebKit as far reaching consequences. It touches all the media functionalities of WebKit. We think this will take some time to get in, then the following patches should be self contained and easier to push. We aim at a June timeline.

webrtcHacks: I have heard many comments about GStreamer not being appropriate for real time applications. Can you address that topic?

Stefan:  That does not match our experience at all. We’ve been using GStreamer for many real time applications since back in 2010 when we showed our first implementation of what eventually became WebRTC, and we’ve consistenly got good real time performance. The fact that there is a lively GStreamer community is also a big plus, that enabled OpenWebRTC to quickly make use of the HW accelerated video codec that became available in iOS 8 – something I have heard webrtc.org still doesn’t for example.

webrtcHacks: How tightly coupled is webrtcinwebkit with OpenWebRTC? Is webrtcinwebkit really a derivative and dependant on OpenWebRTC?

Stefan: Although our initial implementation is backended by OpenWebRTC, the project is designed to fully support other implementations, so no, webrtcinwebkit is not a derivative on OpenWebRTC.

Alex:  Given enough time (and resource), the original plan was to have two back ends for webrtcinwebkit: both OWR from OpenWebRTC and libwebrtc from webrtc.org. It’s not clear yet if we will be able to make it happen, but it’s still a wish.

Browser Engine Share
Chrome Blink 41%
IE Trident 14%
Safari Webkit 14%
Android Browser Webkit 7%
Firefox Gecko 12%
Opera Blink 4%
UC Browser ?? 3%
Nokia Webkit 1%

Browser Usage Share – May 2014 to Apr 2015
Source: http://gs.statcounter.com/#all-browser-ww-monthly-201405-201504-bar ...  Continue reading

One of the biggest complaints about WebRTC is the lack of support for it inside Safari and iOS’s webview. Sure you can use a SDK or build your own native iOS app, but that is a lot of work compared to Android which has Chrome and WebRTC inside the native webview on Android 5 (Lollipop) today. Apple being Apple provides no external indications on what it plans to do with WebRTC. It is unlikely they will completely ignore a W3C standard, but who knows if iOS support is coming tomorrow or in 2 years.

Former guest webrtcHacks interviewee Alex Gouillard came to me with an idea a few months ago for helping to push Apple and get some visibility. The idea is simple – leverage Apple’s bug process to publicly demonstrate the desire for WebRTC support today, and hopefully get some kind of response from them. See below for details on Alex’s suggestion and some additional Q&A at the end.

Note: Alex is also involved in the webrtcinwebkit project – that is a separate project that is not directly related, although it shares the same goal of pushing Apple. Stay tuned for some coverage on that topic.

{“intro-by”: “chad“}

Plan to Get Apple to support WebRTC

The situation

According to some polls, adding WebRTC support to Safari, especially on iOS and in native apps in iOS, is the most wanted WebRTC item today.

The technical side of the problem is simple: any native app has to follow Apple’s store rules to be accepted in the store. These rules state that any apps that “browse the web” need to use Apple provided WebView [rule 2.17] based on the WebKit framework. Safari is also based on WebKit. WebKit does not Support WebRTC… yet!

First Technical step

The webrtcinwebkit.org project aims at addressing the technical problem within the first half of 2015. However, bringing WebRTC support to WebKit is just part of the overall problem. Only Apple can decide to use it in their products, and they are not commenting about products that have not been released.

There have been lots of signs though that Apple is not opposed to WebRTC in WebKit/Safari.

  • Before the Chrome fork of WebKit/WebCore in what became known as blink, Apple was publicly working on parts of the WebRTC implementation (source)
  • Two umbrella bugs to accept implementation of WebRTC in WebKit are still open and active in WebKit’s bugzilla, with an Apple media engineer in charge (Bug 124288 &  Bug 121101)
  • Apple Engineers, not the usual Apple standard representative, joined the W3C WebRTC working group early 2014 (public list), and participated to the technical plenary meeting in November 2014 (w3c members restricted link)
  • Finally, an early implementation of Media Streams and GetUserMedia API in WebKit was contributed late 2014 (original bug & commit).

So how to let Apple know you want it and soon – potentially this year?

Let Apple know!

Chrome and Internet Explorer (IE), for example, have set up pages for web developers to directly give their feedback about which feature they want to see next (WebRTC related items generally rank high by the way).  There is no such thing yet for Apple’s product.

The only way to formally provide feedback to Apple is through the bug process. One needs to have or create a developer account, and open a bug to let Apple know they want something.  Free accounts are available, so there is no financial cost associated with the process. One can open a bug in any given category, the bugs are then triaged and will end up in “WebRTC” placeholder internally.

Volume counts. The more people will ask for this feature, the most likely Apple is to support it. The more requests the better.

But that is not the only thing that counts. Users of WebRTC libraries, or any third party who has a business depending on WebRTC can also raise their case with Apple that their business would profit from Apple supporting WebRTC in their product. Here too, volume (of business) counts.

As new releases of Safari are usually made with new releases of the OS, and generally in or around September, it is very unlikely to see WebRTC in Safari (if ever) before the next release, late 2015.

We need you

You want WebRTC support on iOS? You can help. See below for a step-by-step guide on how.

How to Guide

Step-by-step guide

  1. Register a free Apple Developer account. Whether you are a developer or not does not matter eventually. You will need to make an Apple ID if you do not have one already.
  2. Sign in to the Bug Reporter:
  3. Once signed in, you should see the following screen:
  4. Click on Open, then select Safari:
  5. Go ahead and write the bug report:

It is very important here that you write =&1=&in your own words, you want WebRTC support in Safari. There are a multiple of different reasons you might want it:

  • You’re a developer  you have developed a website that requires WebRTC support, and you cannot use it on Safari. If your users are requesting it, please share the volume of request, and/or share the volume of usage you’re getting on non-safari browsers to show the importance of the this for Apple.
  • You’re a company with a WebRTC product or service. You have the same problem as above, and the same suggestions apply.
  • You’re a user of a website that requires WebRTC, and owner of many Apple devices. You would love to be able to use your favorite WebRTC product or service on your beloved device.
  • You’re a company that propose a plugin for WebRTC in Safari, and you would love to get rid of it.
  • others

Often times, some communities organize “bug writing campaigns” that include boilerplate text to include in a bug.  It’s a natural tendency for reviewers to discount those bugs somewhat because they feel like more of a “me too” than a bug filed by someone that took 60 seconds to write up a report in their own words.

{“author”, “Alex Gouaillard“}

{“editor”, “chad“}

Chad’s follow-up Q&A with Alex

=&2=&What is Apple’s typical response to these bug filing campaigns?

=&3=& I do not have the direct answer to this, and I guess only Apple has. However, here are two very clear comments by an Apple representative: