WebRTC vs HLS: Choosing the right video streaming protocol

As online video consumption continues to grow, so does the need for efficient streaming technologies. WebRTC and HLS have emerged as two popular solutions, each serving different streaming needs. While WebRTC is optimized for real-time communication, allowing direct peer-to-peer connections, HLS excels in delivering adaptive video streams across a wide range of devices. Understanding the strengths, limitations, and ideal use cases of each is essential for developers and businesses alike. In this article, we'll explore the core differences between WebRTC and HLS, helping you make an informed choice based on your streaming requirements.

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What is WebRTC?

WebRTC (Web Real-Time Communication) is a technology that enables real-time communication directly between web browsers, without the need for a third-party plugin. It provides a platform for developers to build applications that support features like video conferencing, voice calling, and screen sharing.

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Key features of WebRTC streaming protocol

WebRTC (Web Real-Time Communication) is a technology that enables real-time communication directly between web browsers, without the need for a third-party plugin. It provides a platform for developers to build applications that support features like video conferencing, voice calling, and screen sharing.    

Here are some of the key features of WebRTC:

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Peer-to-peer communication

Direct connection: WebRTC establishes a direct connection between the sender and receiver, bypassing intermediaries. This eliminates the latency and potential bottlenecks associated with server-based communication. ‍

Reduced latency: By cutting out the middleman, WebRTC ensures a more responsive and real-time experience for users.

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Real-time media streaming

Audio and video: WebRTC enables the transmission of high-quality audio and video streams in real-time. ‍

Data sharing: In addition to media, WebRTC allows for the exchange of data between applications, making it suitable for collaborative tools and interactive experiences.

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Data channels

Beyond media: Data channels provide a mechanism for exchanging data other than audio and video, such as text messages, application-specific information, or control signals.

Collaborative applications: This feature is particularly useful for applications that require real-time collaboration, such as online gaming, collaborative editing, and remote assistance.

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API support

JavaScript integration: WebRTC offers JavaScript APIs that developers can use to easily incorporate real-time communication features into their web applications.

Developer-friendly: The APIs are designed to be intuitive and accessible, making it easier for developers to build WebRTC-enabled applications.

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Cross-browser compatibility

Universal reach: WebRTC is supported by major web browsers, ensuring that your applications can reach a wide audience. ‍

Consistent experience: Users can enjoy a consistent experience across different devices and browsers.

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Security

Encryption: WebRTC employs encryption to protect user data and prevent unauthorized access.  

Authentication: It also includes mechanisms for authenticating users to ensure the security of communication.

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Scalability

Handling large numbers of users: WebRTC is designed to handle a large number of concurrent connections, making it suitable for large-scale applications like video conferencing platforms and online gaming servers.

Efficient resource utilization: WebRTC optimizes resource usage to ensure efficient performance even with many users.

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How WebRTC works?

The below diagram visually represents the flow of communication and data between web browsers, highlighting the key steps and components involved in establishing and maintaining real-time connections.

In essence, the WebRTC workflow is a process of establishing a direct connection between two web browsers and exchanging media streams and data in real-time. It involves various steps, including signaling, negotiation, SDP (Session Description Protocol), and ICE (Interactive Connectivity Establishment) to ensure a smooth and reliable communication experience.

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What is HLS in live streaming?

HLS (HTTP Live Streaming) is a technology developed by Apple that enables the delivery of live video content over the internet. It works by breaking down a live stream into small, pre-segmented video files called ‘chunks’, typically in the MPEG-TS format. These segments are then delivered to the viewer over HTTP, allowing for flexible and efficient streaming.

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Key features of HLS

Server-based: HLS requires a server to process the live stream and create the segmented files.  

Adaptive bitrate: HLS supports adaptive bitrate streaming, which allows the server to dynamically adjust the video quality based on the viewer's network conditions. This ensures optimal playback quality, even in environments with fluctuating bandwidth.

HTTP delivery: HLS uses HTTP, a widely supported protocol, to deliver the segmented video files. This makes it compatible with a wide range of devices and platforms.

Fragmented MP4 (fMP4): HLS can also use fMP4 segments, which are smaller and more efficient than MPEG-TS segments.

Playlist files: HLS uses playlist files (typically in the .m3u8 format) to provide information about the available segments and their playback order.

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How HLS works

Here's a breakdown of how HLS works:

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Server-side processing

• Stream reception: The server receives the live video stream from the source, such as a camera or screen capture. ‍
• Segmentation: The server divides the live stream into smaller, manageable segments. These segments typically have a fixed duration, such as 10 seconds.
• ‍Playlist creation: The server generates a playlist file (usually in the .m3u8 format) that contains metadata about the segments, including their duration, URL, and other relevant information.

Segment delivery

• HTTP transfer: The server delivers the segmented video files and the playlist file to the viewer over HTTP.
• ‍Efficient transmission: HTTP is a widely supported and efficient protocol for delivering media content.

Playlist Parsing

• Segment information extraction: The viewer's player parses the playlist file to obtain information about the available segments, their playback order, and their duration.
• ‍Playback planning: The player uses this information to plan the playback sequence and determine which segments to download.

Segment download and playback

• Sequential download: The player downloads the required segments from the server in the order specified in the playlist file. ‍
• Decoding and rendering: The downloaded segments are decoded and rendered by the player, creating a smooth and continuous playback experience.

Adaptive bitrate

• Quality adjustment: If the viewer's network conditions change, the player can request a different quality segment from the server.
• ‍Switching: The server can respond by delivering a segment with a higher or lower bitrate, ensuring optimal playback quality based on the available bandwidth.

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Overview of HLS architecture

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Why to choose WebRTC: Beyond the core features

WebRTC's combination of real-time capabilities, user experience benefits, business advantages, and technical benefits make it a compelling choice for developers and businesses seeking to build interactive and engaging web applications.

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User experience benefits:

• Reduced latency: WebRTC's peer-to-peer nature minimizes latency, resulting in a more responsive and engaging user experience. ‍
• High-quality media: WebRTC supports high-quality audio and video streaming, enhancing the overall user experience. ‍
• Interactivity: WebRTC enables real-time interactions, such as video conferencing, screen sharing, and collaborative tools.

Business benefits:

• Cost-effectiveness: WebRTC eliminates the need for expensive infrastructure, making it a cost-effective solution for businesses. ‍
• Scalability: WebRTC can handle a large number of concurrent connections, making it suitable for businesses with growing user bases. ‍
• Integration: WebRTC can be easily integrated into existing web applications, reducing development time and costs. ‍
• Cross-platform compatibility: WebRTC's support for multiple platforms ensures a wider reach for your application.

Technical advantages:

• Open standards: WebRTC is based on open standards, ensuring interoperability, and avoiding vendor lock-in. ‍
• Flexibility: WebRTC offers a high degree of customization, allowing developers to tailor the communication experience to their specific needs. ‍
• Security: WebRTC incorporates security features like encryption and authentication to protect user data.

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Why to choose HLS: Beyond the core features

While HLS (HTTP Live Streaming) is primarily known for its server-based architecture and adaptive bitrate capabilities, customers often choose it for the following additional reasons:

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User experience benefits:

• Wide compatibility: HLS is supported by a wide range of devices and platforms, ensuring a broader reach for your content. ‍
• Adaptive streaming: HLS's ability to adjust video quality based on network conditions provides a smoother viewing experience for users with varying internet speeds. ‍
• Offline playback: Some HLS implementations allow for offline playback, enabling users to watch content even when they're not connected to the internet.

Business benefits:

• Scalability: HLS can handle large-scale streaming events and accommodate a growing audience.
• ‍Reliability: The server-based architecture of HLS can provide a more reliable and consistent streaming experience compared to peer-to-peer solutions. ‍
• Cost-effectiveness: HLS can be a cost-effective solution for businesses, especially when compared to other streaming technologies that require significant infrastructure.

Technical advantages:

• Flexibility: HLS offers flexibility in terms of segment format, playlist format, and other parameters, allowing for customization to meet specific requirements. ‍
• Integration: HLS can be easily integrated into existing web applications and platforms. ‍
• Security: HLS can be secured using various mechanisms, such as encryption and access control.

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HLS's combination of wide compatibility, adaptive streaming, scalability, and other benefits make it a popular choice for businesses and content creators seeking to deliver high-quality live streaming experiences.

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Key differences between WebRTC and HLS

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Some real-world use cases of WebRTC

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Virtual assistant devices

The virtual digital assistant market is expected to grow by a factor of three by 2021, according to Tractica. One-way conversational assistants such as Amazon Alexa, Google Assistant, and Apple's Siri serve the majority of this market, and the devices they run on have become highly sought-after pieces of technology.

Amazon uses WebRTC for Alexa as well as several other products, including its online meetings and conferencing software, Amazon Chime, and a browser-based version of its Alexa devices.  

Google Duplex uses real-time communications and artificial intelligence (AI) that allows users to have natural conversations and carry out real-world tasks over the phone. Similarly, Google Dialogflow enables developers to build voice and text-based conversational interfaces, including voice apps and chatbots.  
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Surveillance  

Privacy and protection concern from governments, businesses, and consumers continue to rise as our society becomes more connected. According to IHS Markit, 130 million surveillance cameras are expected to ship globally in 2018, compared to fewer than 10 million shipped in 2006. Though surveillance has classically required at least one human being, that has begun to change. Now, facial recognition, pattern recognition, infrared, and other AI algorithms are aiding surveillance systems in identifying malicious behavior. With WebRTC, these systems can send automated alerts, which video surveillance technologies such as Amaryllo and ring.com already are doing.

Internet of things (IoT)

Globally, about 127 new devices are connected to the Internet every single second, according to a McKinsey Global Institute report. The IoT is experiencing significant growth, and the most important thing coming out of the IoT is the data passed between the machine-to-machine connections. This is what makes WebRTC prime for use in the IoT. One of many examples of how the IoT benefits from WebRTC is DroneSense, a software platform that powers drone and uses real-time communications for video conferencing.
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Connected and self-driving automobiles

The number of autonomous vehicles expected by 2040 is estimated at more than 33 million globally, IHS Markits has reported. Cadillac, Mercedes, and Tesla are each in the process of implementing self-driving cars, among others.

Self-driving technology companies are implementing real-time communications, especially WebRTC, in high-profile self- and assisted-driving automobiles, like those from Waymo. It has the potential to be an easy-to-implement way to communicate, monitor, and control cars.

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Some real-time use cases of HLS

HLS (HTTP Live Streaming) isn't inherently designed for real-time interaction like WebRTC. However, it can be used in situations that have a real-time element, especially when combined with other technologies. Here are some potentials "real-time adjacent" use cases for HLS:

• Live streaming with chat features: Imagine a live sports event streamed using HLS. While the core video stream isn't truly real-time (there's a slight delay), viewers can participate in a live chat alongside the stream, creating a sense of real-time interaction and community.  

• Interactive live Q&A sessions: During a live product demonstration or presentation streamed with HLS, viewers can submit questions in real-time through a chat or dedicated platform. Moderators can then address these questions live, creating a semi-interactive experience.
  

• Augmented reality (AR) applications with pre-recorded content: Suppose an AR app uses HLS to deliver pre-recorded 3D models or video overlays. While the core content isn't truly real-time, the user's interaction with the AR environment can feel real-time due to the device's processing and positioning.

• Live polling and voting during broadcasts: A live news broadcast streamed with HLS might integrate real-time audience polling. Viewers can vote on questions in real-time, and the results are displayed on the broadcast with minimal delay, creating a sense of interaction.

• Hybrid video conferencing with live content: A corporate meeting might combine live presentations or speeches delivered via HLS with interactive video conferencing segments using WebRTC. This allows for both live content delivery and real-time interaction.
  

• Real-time data visualization with HLS overlays: HLS can be used to display pre-recorded or live charts and graphs. Although not truly real-time data visualization, combining HLS with real-time data feeds (through other protocols) can create a dynamic and informative experience.

Important note: While HLS can be used in situations with real-time elements, it's not ideal for applications requiring ultra-low latency and true two-way communication. For those needs, WebRTC is a better choice.

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Hybrid approaches combining WebRTC and HLS

In some scenarios, adopting a hybrid approach that combines WebRTC and HLS can be highly effective, especially when balancing the needs for real-time interactivity and broad video delivery. Here's a deeper dive into how developers might implement such a solution:

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Real-time interaction with WebRTC:
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Use case: WebRTC excels in scenarios where low-latency communication is crucial, such as live chat, video conferencing, or interactive components during a live event.

Implementation: Developers can integrate WebRTC for real-time interactions by setting up signaling servers to handle peer-to-peer connections. Libraries and frameworks like simple-peer or peerjs can simplify the WebRTC integration. WebRTC's peer-to-peer data channels allow for efficient, low-latency messaging between users.

Optimization: Ensure that the WebRTC configuration is optimized for minimal latency and high quality. This involves fine-tuning codec settings (e.g., VP8 or H.264), handling network conditions, and implementing appropriate error recovery mechanisms.

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Broad video delivery with HLS:
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Use case: HLS is well-suited for delivering video content to a large audience with varying network conditions. It's ideal for streaming pre-recorded or live video content that doesn't require real-time interaction.

Implementation: Implement HLS by encoding video into multiple bitrates and segmenting it into chunks. This can be achieved using tools like FFmpeg for encoding and segmenting. Deploy an HLS-compatible media server (e.g., AWS Elemental MediaPackage) to serve the content and handle adaptive bitrate streaming.

Optimization: Optimize HLS streams for performance by configuring segment lengths, tuning bitrate ladders, and ensuring efficient CDN distribution. Implement manifest prefetching and caching strategies to reduce startup times and improve playback performance.

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Conclusion

The choice between WebRTC and HLS depends largely on your application's specific requirements. WebRTC is ideal for real-time, interactive experiences, while HLS is better suited for broader compatibility and adaptive streaming. To choose the right technology, consider factors such as latency, interactivity, device support, and scalability.

At FastPix, we use HLS to deliver adaptive bitrate streaming, ensuring smooth, high-quality playback on any device, regardless of network conditions. HLS excels in scalability and reliability, making it perfect for widespread content delivery.