The concept of video streaming is that when a user clicks on the play button on a streaming platform, the video starts playing immediately, more or less smoothly towards the end. But for this scenario to happen, a lot of technologies have to be integrated into the background. And one of the significant concepts among all is adaptive bitrate streaming. Adaptive bitrate streaming ensures the best video quality and viewing experience- Regardless of the software, connection, or device. This blog is written for people who would like to get into the ins and outs of the fundamental principles of ABR.
How does adaptive bitrate stream work?
This blog will discuss everything about adaptive bitrate streaming, what is adaptive bitrate streaming, how it works, and why it matters. But, first, let’s segue into the details by looking at a common scenario. The process involves encoding the source video at different bit rates and dividing each bit rate stream into small parts. The length of each segment is between 2-10 seconds. The video player at the user’s side can take advantage of adaptive bitrate streaming and switch to various bitrates identifying the segments that match with the bandwidth on the user’s device.
We all might have been in a situation where a video takes up forever to buffer. As a viewer, you can always choose between going to another video streaming site. But as a video streaming platform, it is a loss for you because you end up losing your important customers. Fluctuating internet speed results in poor quality streams, and the video starts buffering.
Buffering happens due to the fact that the network is not able to download the video files quickly enough to keep the video playback going on. This is why most video players come with the integration of selecting different bitrates. Users can switch to the appropriate bitrate according to the speed of their internet connection. However, leaving the choice to users itself can be a hassle. This is where adaptive bitrate streaming becomes significant. Before going into the details, let’s understand the concept of bitrate.
What is Bitrate
Bitrate is the rate at which data bits travel over a network connection from one computer system to another. Faster internet connections have a higher level of bitrate than slower network connections. Video bitrate is the amount of data required to encode a video of one-second lengths. Mbps is the unit that is used to measure bitrate.
If the video bitrate is high, it results in an excellent quality video streaming experience. Whereas, a low berate results in low quality and buffered video streaming experience. HD videos require a bit rate of 5-20 Mbps for smooth playback. Standard definition videos require 1-6 Mbps and high-quality videos need a bit rate of 2Mbps.
Adaptive bitrate streaming is technically a strategy used during streaming multimedia content over the computer for managing the streaming performance. While most video streaming techniques relied on RTP or RTSP earlier, modern streaming technologies are now built to support HTTP transmission over large distribution networks. The working of ABS goes like this- It dynamically monitors the CPU and memory capacity of the device and makes adjustments accordingly to alter the video quality.
The main steps in the working of ABR streaming are as follows
Preparing video files
Video broadcasters encode video files to different bitrates based on the target streaming profile to prepare for ABR. Most video streaming websites are capable of creating different video formats from a single source video file.
Starting the video player
Online video players require a manifest file download for video playback. This file has all the information on the video segment, including the streaming profile info. Video players can use manifest files as guides and leverage them to request the right video segments suitable for different devices and network connections.
The video player plays back a video segment and moves towards downloading the next segment. Video players use their ABR algorithm to determine which bit rates they must use next. Different video players use different algorithms to determine when and how to make the modifications mentioned above.
Let’s explore some of the common video selection algorithms
This algorithm measures how quickly the player downloaded the previous video streams to decide which bitrate to request next.
Buffer-based algorithms analyze and manage the buffer occupancy to make sure there is always enough content buffered for playback. If the download speed becomes a bit slower, it compensates for the speed loss requesting for video chunks that are lower in bitrate.
Hybrid algorithms take the best both throughout and buffered based. It gauges both download speed and buffers occupancy, which makes the best selection algorithm.
Progressive download vs. adaptive streaming
A progressive download delivery method is where a video is downloaded to the viewer’s computer and stored in a temporary directory. The video will start the playback soon as it is saved locally. The video is delivered through the standard HTTP protocol, just like any other webpage.
On the other hand, streaming videos deliver content via a streaming server without the file being downloaded to the user’s device. One of the major advantages of adaptive bitrate video streaming is that only the bandwidth that the user has viewed, as only the portion of the video that has been viewed, has been delivered. Every content is on the client-side, and nothing is kept on the client-side. The videos are delivered via RTMP (Real Time Messaging Protocol).
In practice, you won’t be able to understand whether the videos are streamed or delivered through progressive download. However, progressive download is far from optimal. The streaming quality will suffer as the same video file is used for all types of bandwidth and devices. No matter the type of issues that arise, be it low video quality videos, buffering lag, or pixelation issues, the outcome is the same- A bad viewing experience. The best approach to adopt is to use adaptive bitrate streaming, which solves all the above problems using its adaptability to varied network conditions, devices, and bandwidth.
What makes adaptive bitrate streaming the right approach
As you might have guessed, adaptive bitrate streaming is undoubtedly the best delivery choice for streaming platforms. Here is a quick review of why ABR streaming is the best choice.
The best user experience
Adaptive streaming is the least interruptive delivery method for streaming platforms. It eliminates buffering problems and tailors the content to suit different devices resulting in the best user experience.
Faster startup and smooth video playback
Adaptive bitrate streaming supports the faster startup of video playback as it begins processing low-quality renditions before upgrading to HD quality according to the capabilities of the user’s network.
Optimized for devices
More than before, more users are watching videos from their smartphones and tablets. That is why your video streaming platform needs to cater to audiences who watch videos from screens of different types and shapes.
Improves brand perception
Consider the best viewing experience a smooth and buffer less video stream offers; your audience will surely remember it. This will help to enhance their perception of your streaming business as a more professional and reliable brand.
What are the different types of streaming protocols?
Video streaming protocols are a fundamental element of being able to send and play videos on your devices. It is a method of delivering audio or video or both over the internet to enable a smooth playback experience. Understanding the streaming protocol is important as some of them can handle ABR streaming better. It is also critical to consider what kind of protocol the device supports when choosing the protocol. Each protocol serves its function and differs in terms of factors like compatibility and latency.
Different streaming protocols
Real-time messaging protocol (RTMP)
Created by Macromedia and later acquired by Adobe, RTMP is a universally accepted streaming protocol. It is based on TCP that was designed for on-demand and live streaming with the purpose of maintaining low latency. While this protocol was developed initially to work with flash players, most browsers have switched to HTML5 players. RTM can transmit video for an encoder; it’s not really great for adaptive bitrate video streaming.
Dynamic adaptive streaming over HTTP (MPEG- DASH)
Popularly known as MPEG-DASH, Dynamic adaptive streaming is an HTTP-based streaming protocol that is currently gaining traction. It is a common alternative for HLS in the industry as well. Developed by Moving Pictures Expert Group (MPEG), it is an open-source choice that can be customized to support any audio or video codec. It also supports ABR streaming but is not supported by Apple software.
Web real-time communications (WebRTC)
One of the latest modern video streaming protocols showcasing the fastest audio and video streaming capabilities, WebRTC is near-instantaneous. WebRTC was used primarily for peer-peer audio and video sharing between browsers. It mainly supports video conferencing and lacks scalability.
Offering the best user experience to your viewers is one of the best ways video streaming platforms can distinguish themselves in the highly competitive streaming industry. Now that you are familiar with ABR streaming and its significance, you would have understood ABR’s importance for uninterrupted video playback. However, implementing ABR can be challenging, especially if you don’t have the right resources. Choose a video streaming software that integrates HTM5 player and enables you to offer adaptive bitrate streaming to your users. If you need to know more about adaptive bitrate streaming players, we are here to help you. Please get in touch with us for more assistance and support.