Adaptive bitrate streaming (ABR) is a technique for streaming video that adjusts video properties like bitrate and resolution to better fit the client's needs. By changing what quality of video segments are transferred to best fit client-side bandwidth factors, such as device type and internet speed. ABR offers video players multiple versions of a video, with different resolutions and bitrates, prioritizing user experience by reducing buffer time and interruptions.
Why is ABR important for improving video playback?
In short, adaptive bitrate streaming ensures the most optimal streaming experience by constantly evaluating a viewer's network connection. A device’s available bandwidth is subject to constant fluctuation due to factors like weather, movement, and even spontaneous dips in Wi-Fi. ABR enhances playback quality by supporting video players’ needs, such as allowing the player to switch between versions and bitrate load to accommodate changes in internet speed.
How adaptive bitrate streaming works
ABR requires video content that has been encoded into multiple versions at different bitrates and resolutions (these versions are often called renditions). The player then requests a rendition based on what it can accommodate with its available playback conditions. If playback conditions change, the player can switch to a different rendition as often as it needs, and ABR is what makes the process seamless. Let’s take a closer look at these steps.
Encoding and segmenting
During encoding, raw video data is compressed into multiple renditions at different bitrates and resolutions. Each version is then divided into small video segments, which is known as chunked encoding. Various encoding settings are used to create these video segments, to accommodate a multitude of quality options and prepare them for transport to a playback device. After segmentation, a manifest file is created to show players how to access the video segments.
Dynamic bitrate selection
When a video player receives a variety of quality options, it selects the rendition with a bitrate that accommodates the capabilities of the user’s device and network bandwidth, which is measured using available bandwidth estimations. Once a device selects the initial version, it will retrieve segments of that rendition and play the video.
Adaptation algorithms
During playback, the device continuously monitors network conditions, buffer status, and playback buffer length. If bandwidth decreases, the player will use the ABR algorithm to switch between higher or lower bitrate versions as needed, selecting the appropriately versioned segments. The algorithm may primarily use the speed of the network connection and the buffer level in the player to determine the appropriate bitrate, but this depends on which algorithm it is using.
Benefits of using adaptive bitrate streaming
Improved video playback quality
ABR optimizes video playback quality by adjusting its rendition in real time, allowing the device to swap quality levels during playback. As a result, ABR delivers the highest possible video quality while also prioritizing continuous streaming for viewers, no matter their network conditions.
Reduced buffering for smoother playback
ABR minimizes buffering by constantly assessing the viewer's available bandwidth and adjusting video quality accordingly. If the internet connection is too weak and threatens to buffer, ABR adjusts the video’s bitrate load to reduce buffering and support uninterrupted streaming — the result of which is a smooth viewing experience.
Enhanced user satisfaction
By providing consistently high-quality video playback in spite of varying network conditions, ABR boosts viewer satisfaction. Users no longer need to worry about manually adjusting video quality settings when they’re experiencing slow internet speeds. With ABR, viewers can focus on the content, which leads to increased engagement and higher customer retention for streaming services.
Use cases for adaptive bitrate streaming
Live streaming events
ABR supports live streaming, making it an invaluable asset for events like webinars, sports broadcasts, concerts, and more. As many viewers with different devices join live streams, network conditions can fluctuate dramatically. ABR adapts to every viewer's bandwidth, network conditions, and device capabilities to deliver a consistent, high-quality viewing experience for all.
On-demand video services
On-demand video streaming platforms like Netflix or Hulu are host to vast, ever-growing content libraries. ABR dynamically adjusts the quality of each video on these platforms according to a viewer's network connection, which is nonnegotiable for services with large global audiences, where network conditions can differ significantly from region to region.
User-generated content
Similarly to on-demand video platforms, user-generated content (UGC) services like YouTube and TikTok rely on ABR to stream UGC. Because users access UGC platforms from a variety of different devices, the quality and resolution of their videos vary widely. ABR enables UGC platforms to optimize playback by adapting the stream to the viewer's specific conditions.
Setting up adaptive bitrate streaming
When implementing ABR into a server environment, there are several setup factors to keep in mind.
First, you should choose a streaming protocol that meets your server’s needs. HLS, for example, is one of the most commonly used protocols owing to its high versatility and scalability for live and OTT streaming. Alternatively, MPEG-DASH is an ideal protocol option because it does not require specific encoding formats, but it does not work on Apple devices.
On top of selecting the proper streaming protocol, you’ll also want to focus on using a variety of bitrates and choosing an appropriate bitrate player. If balancing these requirements sounds overwhelming, though, don’t worry — that’s where Mux comes in. Mux prepares your video for the HLS protocol and supports video playback devices to automatically choose the right video size and resolution based on their detected network conditions. On top of that, Mux’s adaptive encoding processes deliver an optimized adaptive bitrate ladder so you won’t need to worry about which resolution and bitrate combinations to use. Lastly, Mux Player supports ABR streaming via HLS. This means you can design the perfect video player that not only looks great but can be used with any device and in any network condition.
ABR challenges and solutions
There are a few challenges to look out for when implementing adaptive bitrate streaming. Creating any effective algorithm is complex work, and adaptive bitrate streaming algorithms are no different. Without strong management solutions to oversee buffering, device variability, network oscillations, and latency, viewers may experience decreased quality and overall streaming performance. Additionally, if your algorithm wasn’t built to handle a large number of users, it may not be able to perform optimally during periods of high traffic.
Luckily, Mux’s Video API is designed to scale, so you’ll never have to worry about spikes in usage or the size of your video files. We specialize in the effective configuration of video encoders so that your viewers have high-quality, uninterrupted video experiences.
A bright future for adaptive bitrate streaming
Adaptive bitrate streaming is an important technology for delivering seamless, high-quality video content to users, regardless of their device or network capabilities. With ABR, neither streaming services nor viewers need to manually select the correct video resolution for their device.
ABR has revolutionized the streaming industry by increasing both watch time and viewer engagement, combining beautiful players and reliable CDNs, and thus creating the best viewing experiences. As the demand for online video streaming grows, so too will the demand for ABR — it’s become the industry standard, and it’s here to stay.
Mux provides an all-in-one solution for configuring video to meet its full potential. Our API offers best-in-class encoding techniques, popular streaming protocols, and an ABR-compatible player to give developers a better building experience and viewers a better streaming experience.
To get started with Mux, request a demo today!