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WebRTC live streaming to unlimited viewers, with sub-second latency

WebRTC live streaming to unlimited viewers, with sub-second latency

Creators and broadcasters expect to be able to go live from anywhere, on any device. Viewers expect “live” to mean “real-time”. The protocols that power most live streams are unable to meet these growing expectations.

In talking to developers building live streaming into their apps and websites, we’ve heard near universal frustration with the limitations of existing live streaming technologies. Developers in 2022 rightly expect to be able to deliver low latency to viewers, broadcast reliably, and use web standards rather than old protocols that date back to the era of Flash.

Today, we’re excited to announce in open beta that Cloudflare Stream now supports live video streaming over WebRTC, with sub-second latency, to unlimited concurrent viewers. This is a new feature of Cloudflare Stream, and you can start using it right now in the Cloudflare Dashboard — read the docs to get started.

WebRTC with Cloudflare Stream leapfrogs existing tools and protocols, exclusively uses open standards with zero dependency on a specific SDK, and empowers any developer to build both low latency live streaming and playback into their website or app.

The status quo of streaming live video is broken

The status quo of streaming live video has high latency, depends on archaic protocols and is incompatible with the way developers build apps and websites. A reasonable person’s expectations of what the Internet should be able to deliver in 2022 are simply unmet by the dominant set of protocols carried over from past eras.

Viewers increasingly expect “live” to mean “real-time”. People want to place bets on sports broadcasts in real-time, interact and ask questions to presenters in real-time, and never feel behind their friends at a live event.

In practice, the HLS and DASH standards used to deliver video have 10+ seconds of latency. LL-HLS and LL-DASH bring this down to closer to 5 seconds, but only as a hack on top of the existing protocol that delivers segments of video in individual HTTP requests. Sending mini video clips over TCP simply cannot deliver video in real-time. HLS and DASH are here to stay, but aren’t the future of real-time live video.

Creators and broadcasters expect to be able to go live from anywhere, on any device.

In practice, people creating live content are stuck with a limited set of native apps, and can’t go live using RTMP from a web browser. Because it’s built on top of TCP, the RTMP broadcasting protocol struggles under even the slightest network disruption, making it a poor or often unworkable option when broadcasting from mobile networks. RTMP, originally built for use with Adobe Flash Player, was last updated in 2012, and while Stream supports the newer SRT protocol, creators need an option that works natively on the web and can more easily be integrated in native apps.

Developers expect to be able to build using standard APIs that are built into web browsers and native apps.

In practice, RTMP can’t be used from a web browser, and creating a native app that supports RTMP broadcasting typically requires diving into lower-level programming languages like C and Rust. Only those with expertise in both live video protocols and these languages have full access to the tools needed to create novel live streaming client applications.

We’re solving this by using new open WebRTC standards: WHIP and WHEP

WebRTC is the real-time communications protocol, supported across all web browsers, that powers video calling services like Zoom and Google Meet. Since inception it’s been designed for real-time, ultra low-latency communications.

While WebRTC is well established, for most of its history it’s lacked standards for:

  • Ingestion — how broadcasters should send media content (akin to RTMP today)
  • Egress — how viewers request and receive media content (akin to DASH or HLS today)

As a result, developers have had to implement this on their own, and client applications on both sides are often tightly coupled to provider-specific implementations. Developers we talk to often express frustration, having sunk months of engineering work into building around a specific vendor’s SDK, unable to switch without a significant rewrite of their client apps.

At Cloudflare, our mission is broader — we’re helping to build a better Internet. Today we’re launching not just a new feature of Cloudflare Stream, but a vote of confidence in new WebRTC standards for both ingestion and egress. We think you should be able to start using Stream without feeling locked into an SDK or implementation specific to Cloudflare, and we’re committed to using open standards whenever possible.

For ingestion, WHIP is an IETF draft on the Standards Track, with many applications already successfully using it in production. For delivery (egress), WHEP is an IETF draft with broad agreement. Combined, they provide a standardized end-to-end way to broadcast one-to-many over WebRTC at scale.

Cloudflare Stream is the first cloud service to let you both broadcast using WHIP and playback using WHEP — no vendor-specific SDK needed. Here’s how it works:

Cloudflare Stream is already built on top of the Cloudflare developer platform, using Workers and Durable Objects running on Cloudflare’s global network, within 50ms of 95% of the world’s Internet-connected population.

Our WebRTC implementation extends this to relay WebRTC video through our network. Broadcasters stream video using WHIP to the point of presence closest to their location, which tells the Durable Object where the live stream can be found. Viewers request streaming video from the point of presence closest to them, which asks the Durable Object where to find the stream, and video is routed through Cloudflare’s network, all with sub-second latency.

Using Durable Objects, we achieve this with zero centralized state. And just like the rest of Cloudflare Stream, you never have to think about regions, both in terms of pricing and product development.

While existing ultra low-latency streaming providers charge significantly more to stream over WebRTC, because Stream runs on Cloudflare’s global network, we’re able to offer WebRTC streaming at the same price as delivering video over HLS or DASH. We don’t think you should be penalized with higher pricing when choosing which technology to rely on to stream live video. Once generally available, WebRTC streaming will cost $1 per 1000 minutes of video delivered, just like the rest of Stream.

What does sub-second latency let you build?

Ultra low latency unlocks interactivity within your website or app, removing the time delay between creators, in-person attendees, and those watching remotely.

Developers we talk to are building everything from live sports betting, to live auctions, to live viewer Q&A and even real-time collaboration in video post-production. Even streams without in-app interactivity can benefit from real-time — no sports fan wants to get a text from their friend at the game that ruins the moment, before they’ve had a chance to watch the final play. Whether you’re bringing an existing app or have a new idea in mind, we’re excited to see what you build.

If you can write JavaScript, you can let your users go live from their browser

While hobbyist and professional creators might take the time to download and learn how to use an application like OBS Studio, most Internet users won’t get past this friction of new tools, and copying RTMP keys from one tool to another. To empower more people to go live, they need to be able to broadcast from within your website or app, just by enabling access to the camera and microphone.

Cloudflare Stream with WebRTC lets you build live streaming into your app as a front-end developer, without any special knowledge of video protocols. And our approach, using the WHIP and WHEP open standards, means you can do this with zero dependencies, with 100% your code that you control.

Go live from a web browser with just a few lines of code

You can go live right now, from your web browser, by creating a live input in the Cloudflare Stream dashboard, and pasting a URL into the example linked below.

Read the docs or run the example code below in your browser using Stackbltiz.

<video id="input-video" autoplay autoplay muted></video>
import WHIPClient from "./WHIPClient.js";

const url = "<WEBRTC_URL_FROM_YOUR_LIVE_INPUT>";
const videoElement = document.getElementById("input-video");
const client = new WHIPClient(url, videoElement);

This example uses an example WHIP client, written in just 100 lines of Javascript, using APIs that are native to web browsers, with zero dependencies. But because WHIP is an open standard, you can use any WHIP client you choose. Support for WHIP is growing across the video streaming industry — it has recently been added to Gstreamer, and one of the authors of the WHIP specification has written a Javascript client implementation. We intend to support the full WHIP specification, including supporting Trickle ICE for fast NAT traversal.

Play a live stream in a browser, with sub-second latency, no SDK required

Once you’ve started streaming, copy the playback URL from the live input you just created, and paste it into the example linked below.

Read the docs or run the example code below in your browser using Stackbltiz.

<video id="playback" controls autoplay muted></video>
import WHEPClient from './WHEPClient.js';
const url = "<WEBRTC_PLAYBACK_URL_FROM_YOUR_LIVE_INPUT>";
const videoElement = document.getElementById("playback");
const client = new WHEPClient(url, videoElement);

Just like the WHIP example before, this one uses an example WHEP client we’ve written that has zero dependencies. WHEP is an earlier IETF draft than WHIP, published in July of this year, but adoption is moving quickly. People in the community have already written open-source client implementations in both Javascript, C, with more to come.

Start experimenting with real-time live video, in open beta today

WebRTC streaming is in open beta today, ready for you to use as an integrated feature of Cloudflare Stream. Once Generally Available, WebRTC streaming will be priced like the rest of Cloudflare Stream, based on minutes of video delivered and minutes stored.

Read the docs to get started.

Source:: CloudFlare