Before you’ve gotten to the point where you questioned what video bitrate is, you’ve probably already purchased and set up all your streaming equipment including video camera, microphone, and lighting. Maybe you have also created your video content strategy and found a platform that you wish to stream to. If you have a WordPress website, consider streaming directly to your site using a plugin such as WpStream.
Now that all that is set up, you want to find out what to do next in order to broadcast the highest quality live stream. Keep in mind that you will have to be broadcasting at a good quality in order to keep your viewers entertained and coming back. This is regardless of their device or internet connection. One way to control this is to make sure you:
- Have a good internet connection – even the smallest interruptions can cause issues
- Choosing the optimal video bitrate for your needs
In this article, you will learn everything you know about video bitrate, resolution, frame rate, and how they all work together to deliver the best live stream of your viewers ‘lives’. Pun intended.
What is Video Bitrate?
Bitrate refers to the amount of data sent over to a website while streaming. Higher bitrates use up more internet bandwidth. However, it can also improve video quality. Video bitrate is, quite simply, the amount of video data transferred over the internet at any given time. A high bitrate is one of the most important variables in the overall quality of your live stream or video-on-demand. If your video has a high bitrate, as well as a high resolution and frame rate (more on these terms later), it will deliver a high-quality video that streams smoothly to your visitors.
However, it’s important to note that increasing the bitrate may not always be the most efficient option. This is because the increase in video quality is only advantageous up to a point. In order to maintain a stable stream, the bitrate should be less than half of the overall upload speed. For example, streaming at a 1080p resolution requires a higher bitrate than streaming at 720p. Bitrates will generally range from 1000 kbps to 6000 kbps. To run an internet speed test, make sure you follow this link.
From our test we got between 8 and 10 Mbps upload speed, which means we can comfortably set our bitrate to 4000 kbps. This is half of the lowest upload speed encountered.
For general guidance, check the following table to see what options to set:
Please note that these are guideline figures for the most common FPS settings (25/30 FPS). For higher frame rates such as 50 or 60 FPS you should multiply your figures by 1.5.
Each piece of content is distinct and the motion determines the quality. Higher bitrates are required when more movement occurs (sports and gaming) . On the other hand, having a smaller bitrate, FPS, and resolution in video streams that are ‘talking heads’ or lack quick movement can deliver great imagery. Therefore, consider the type of live streams you will be carrying out and based on that, you can adjust these settings.
The best thing to do is experiment with the video you plan to live-stream and choose the lowest bitrate that offers good quality output to deliver the optimal settings for your broadcast.
The Measure of Video Bitrate
Bitrate is measured in bits per second or bps. While a measurement such as kilobits per second (kbps) is enough to measure audio and other smaller files, it is insufficient to convey how much data is swiftly moved with video files. The bitrate of a video file is measured in megabits per second, or Mbps. This figure represents the millions of pieces of data that are uploaded and downloaded to and from the internet every second.
The lower the bitrate your video requires, the smaller the resolution your video requires, and the lower the resolution of the screen a user will be viewing. But, as the resolution of the video increases, the video’s bitrate needs to increase as well. Moreover, the internet speed needs to be taken into account as well.
A higher bitrate is good for viewers who have better, more stable internet connections. However, to avoid continual buffering and lagging video streams, viewers with lower-quality and less consistent internet connections require a lower bitrate.
Video Bitrate and Video Encoding
Adjusting the bitrate happens at the stage of encoding. This could be when using the browser broadcaster, or through OBS Studio’s settings.
You will find these settings in any external broadcaster and you will have to adjust them before actually going live. This is part of the ‘Encoding’ process. Basically, you choose the bitrate at which you want your video to be sent, and your video encoder compresses the file into a single smooth, steady stream to meet that bitrate. Your videos should also be transcoded, or compressed into a reduced file size to ensure that they are sent to the viewer without interruption.
Video Bitrate and Frame Rate
The frame rate of your video is the frames per second (FPS). The rate at which consecutive images arrive in a video feed or the rate at which images are displayed on screen. This term is universal, meaning that you will find it when referring to cameras, films, and even games. Usually, content is captured at 25 or 30 FPS for amateur streaming. However, for a more effective and high-end streaming experience, the FPS will run at 50-60 FPS. Such instances include UHD gaming or HDR sports.
If you have an older PC or console, most of them will run at about 30 FPS. On the other hand, professional gaming rigs will deliver stable streams at 60 FPS. It is important to note that this is the FPS of your stream and not of your device.
Consider frame rate in the same way as you would a flipbook: the faster you turn a page with a single image (or frame), the more consistent and fluid the whole image appears. Slowing down allows you to view more of the individual images rather than one continuous, moving image. A lower frame rate will lead to more jerky or a slow video view compared to a video with a high frame rate. However, once again, there isn’t an ideal frame rate. It largely depends on what you are broadcasting.
For instance, a classroom with a teacher lecturing their students online will need a lower frame rate compared to a football match because the teacher is most probably sitting in one place and talking to her students. However, the football match will require a higher frame rate because players are running and the football is being kicked from one side of the field to another. You are supposed to capture every detail so thus, require a higher frame rate (and bitrate).
Frame Rate vs. Resolution and Bitrate
So how do frame rate, resolution, and bitrate all work together to help you deliver a high quality live stream? The frame rate and resolution of a video are somewhat related. If you have a higher frame rate, you’re likely to have a better video resolution as well, allowing you to see more details in the video. The bitrate of a video is connected to its frame rate and resolution. The higher the resolution and frame rate, the higher the bitrate must be for a file to travel faster over the internet.
Ideal Bitrates for 8 of the Most Popular Streaming Platforms
|Platform Name||Optimal Video Bitrate||Optimal Audio Bitrate|
|Facebook Live||4 Mbps||128 Kbps|
|WpStream||4 Mbps||128 Kbps|
|Youtube||1.5 to 4 Mbps||128 Kbps|
|Twitch||Up to 8 Mbps||128 Kbps|
|Wistia||2.5 to 4 Mbps||128 Kbps|
|3.5 Mbps||128 Kbps|
|Periscope||2.5 Mbps||128 Kbps|
|Wirecast||Up to 6 Mbps||128 Kbps|
Despite including the table above showing you the ideal bitrates for a few of the most popular streaming platforms, these numbers still vary. Several factors include the type of streaming you will be carrying out, whether you/your viewers have good internet connection, if you are broadcasting a class where there is less movement, or a race car tournament.
The more movement that will be happening on screen, the higher the video bitrate, resolution, and frame rate. If you are live streaming a sports event with a low bitrate, you will see frequent interruptions and lagging happening. We always recommend that whatever event you plan to broadcast, you should first carry out some testing and find out what the best settings are for you. Mix and match different numbers when you are in the encoding process (on OBS, for example) and adjust the video bitrate, resolution, and frame rate.
Once you have found your ideal settings, note them down and go back to them whenever you go live (with a same type of event). You may also want to test the settings when broadcasting from your browser or using other external broadcasters. If you change your internet provider, carry out a speed test and check what your speed is. Based on that, adjust your settings. Remember, your internet connection, bitrate, resolution, and frame rate all work together as a ‘team’ to deliver the best quality broadcast.