Streaming video has become a prominent part of content consumption. The chances are most of us will stream videos on a daily basis, whether that’s watching a YouTube tutorial or a video on Facebook Live. Streaming has become a central means for businesses and influencers to stay connected with their audiences and as streaming has grown in importance, so too has the need for high-quality video.
We are going to look at two key factors affecting video quality – bitrate and resolution – and assess the importance of both when it comes to streaming video.
What is Video Bitrate?
Before looking at the effect of both bitrate and resolution on the quality of video streaming, it’s important to know precisely what is meant by video bitrate and how it works.
Essentially, bitrate is the measure of data transfer speed and the amount of internet bandwidth the transfer will require. In short, it’s the amount of data used to encode a second of video.
Bitrate is generally measured in megabits per second (Mbps). It will occasionally be seen measured in kilobits per second (Kbps) but this is more suitable when used in the context of smaller audio files.
Understanding Bitrate and Video Encoding
To fully understand bitrate it’s important to familiarize yourself with video encoding. Encoding is the process by which RAW video footage is compressed and converted into streamable content that’s compatible with a host of different kinds of devices and smartphones.
In essence, when a video is encoded and compressed, a certain amount of data is removed to make the file size smaller. Raw footage files are too large to successfully stream over the internet and must be trimmed. The bitrate essentially tells the encoder how much to compress the file and how much data to stream.
This means that with a lower bitrate, the more the encoder will compress the video and the less data will be streamed, resulting in a lower quality viewing experience.
As such, encoding is a fundamental part of video streaming and choosing the right encoder can also have an effect on the quality of a video. Encoding is either done using software or hardware and both have their pros and cons depending on your streaming requirements.
Encoding software tends to be more affordable while offering high-quality results. Software is generally used by more beginners and intermediates but is still used by some industry professionals. Hardware can be more expensive and will not bring as good quality results as software. However, due to its specialized nature, encoding will often be faster.
Whether you decide to use software or hardware to encode your video files should really depend on yours and your viewers’ requirements and the regularity with which you’re going to stream.
The Different Types of Bitrate
There are two different kinds of encoding settings: constant bitrate encoding (CBR) and variable bitrate encoding (VBR).
During constant bitrate encoding, videos are segmented into files of consistent size. Due to the large size of the files the viewer must have a strong, reliable internet connection to stream this kind of video. CBR is a fast and efficient form of encoding but does not produce as high-quality results as VBR.
Alternatively, variable bitrate encoding segments video files into chunks of varying size in order to be steadily transmitted while retaining the best image quality possible. As the files generated can be of random size, this can cause problems with buffering if the player struggles to predict the size of each file. The bitrate is calculated by taking an average size of the segments.
Variable bitrate encoding can also be capped in some instances. This is to prevent the encoder producing segments of too high a bitrate and causing streaming issues. Another downside of using variable bitrate encoding is that it’s less widely supported than constant bitrate encoding.
Is High Bitrate Better for Streaming?
So, in simple terms – yes, higher bitrate is better for streaming and produces higher-quality videos.
The lower the bitrate, the more the video is being compressed and the more information the video loses. When lots of information is lost with low bitrate streaming, the result becomes visually perceptible.
There are a number of other factors that contribute to streaming quality though such as the location and bandwidth of your viewers, the kind of devices they’re streaming on and the resolution of the video.
What is Video Resolution?
Resolution is relatively simple. It refers to how many pixels can be displayed and it’s measured with regards to width and height.
It’s generally expressed as a two-dimensional number known as the aspect ratio with width always coming first. For example, the resolution of a Full HD TV would be expressed as 1920×1080.
It can also be given in a simplified form expressing just the measurement for height. In this way, the resolution of a Full HD TV would be given simply as 1080p video.
Is Video Resolution the Same as Frame Rate?
Video resolution is not the same as frame rate. While resolution measures the amount of pixels in each frame, frame rate refers to the frequency at which still images are displayed on the screen.
Frame rate is expressed as frames per second (FPS). The more consecutive images that appear on screen in a second, the smoother and more seamless the video will appear to the viewer.
The frame rate is selected with the camera at the filming stage and different frame rates are suitable for different types of action. Something with a lot of high-energy movement, such as sport, may require a high frame rate for a smoother quality outcome.
Bitrate vs Video Resolution for Streaming
So, after looking at the impacts of both bitrate and resolution on streaming quality, that begs the question: ‘what’s more important?’
A higher bitrate should produce a higher quality video but this is also dependent on the streaming capabilities of your audience. There is little point encoding and streaming in a high bitrate if your viewers don’t have the bandwidth, internet speeds or devices to cope with the amount of data.
Similarly, streaming videos of a higher resolution and frame rate leads to better looking videos but requires a higher bitrate.
In short, both play a pivotal role in the viewing experience and as such, neither can be conclusively said to be more important than the other. You must consider your viewers’ streaming capabilities and the type of video content that you’re streaming to achieve the highest quality results.