Bitrate vs. Resolution for Professional Broadcasting [2021 Update]
Table of Contents
There are some common misconceptions about bitrate and resolution when it comes to professional broadcasting. It is often assumed that bigger is better, but when it comes to bitrate vs resolution, that is simply not the case.
Bitrate and resolution settings can be manipulated to control the quality of an uploaded video or live stream.
Today, we’re going to break down a few different topics related to live encoding. We’ll define encoding, bitrate, and resolution before diving into specific encoder settings. By the end of this post, you’ll know everything you need to know to choose bitrate and resolution settings with confidence.
Let’s get into it.
Table of Contents
- What is Video Encoding?
- What is Video Bitrate?
- What is Video Resolution?
- What Does “FPS” Mean?
- Comparing Bitrate vs. Resolution
- Popular Bitrate and Resolution Setting Combinations
- Other Required Encoder Settings
What is Video Encoding?
Before we dive into bitrates and resolution, it is important to understand the core process of encoding.
The process of encoding can be carried out by either a hardware or software encoder. Beginner, intermediate and even some professional broadcasters stick with software encoders because of their reasonable price point.
Each type of encoder comes with unique pros and cons.
As we mentioned, software encoders are typically affordable. Since you operate them on your computer, you don’t need to worry about lugging around extra equipment if you’re streaming outside of a studio. They are also nice because they can be updated as new versions come out.
The benefit of using a hardware encoder is that it is a dedicated device. This means that since encoding is its primary function, it is typically a little faster and more effective. On the flip side, hardware encoders can be super bulky and expensive. They can also be a bit tricky to set up for inexperienced broadcasters.
If you are not sure where to start with encoders, we recommend testing out a free one like OBS Studio. From there, you can determine whether or not you need the advanced features of a paid one.
What is Video Bitrate?
Video bitrate is a measure of the speed of transfer over the internet and how much bandwidth it will consume. Essentially, it describes the quality of a video.
The most technical way to define bitrate is the “amount of data required to encode a single second of video.” The unit of measurement used here is megabits per second (Mbps).
There are two types of bitrate encoding: constant bitrate (CBR) encoding and variable bitrate (VBR) encoding. Each of these come with their own pros and cons.
1. Constant Bitrate Encoding
As the name suggests, CBR encoding creates consistently sized files. These are typical of greater size and higher quality. In order to be viewed at this size, the viewer must have a strong internet connection.
Encoding with a constant bitrate is a quicker and more efficient process than the variable alternative. Another perk is that it typically maintains audio quality and is well suited for multimedia streaming.
However, there are a couple of notable drawbacks of CBR encoding. It offers limitations to viewers without a strong internet connection since the file sizes are typically large. It also has very little flexibility.
2. Variable Bitrate Encoding
VBR encoding segments files into sizes that are easier to transmit. Since the video is broken into segments that are unequal, the bitrate of the video is calculated by averaging the size of the segments.
Much like the constant alternative, VBR encoding has a few pros and cons. One of the biggest perks of this type of encoding is that it offers both efficiency and flexibility. Due to the smaller size of the files, videos that have been encoded with VBR are easier to store, send, and upload.
Some say that VBR encoding compromises the quality of a video, which is true but it is not usually something to worry about. The downgrades are minimal yet entirely worth the sacrifice.
Streaming with the smaller files allows users with weaker internet to watch the video with limited lagging and buffering, which enhances the viewing experience.
There are a few drawbacks worth mentioning. Variable bitrate encoding is less widely supported than constant bitrate encoding. The actual encoding process also takes a bit longer to carry out.
3. Multi-Bitrate Streaming
As a broadcaster, you should choose a bitrate based on the type of device(s) your audience will use to view the content.
Many broadcasters have diverse audiences from different locations with different internet speeds, so they use multi-bitrate streaming with an adaptive video player. This automatically streams the optimal file size according to the internet speed of each unique viewer.
This type of streaming recognizes that bitrates are not a one-size-fits-all sort of deal. If you are looking to provide the best quality streams for all of your viewers, you should choose an online video host that is capable of multi-bitrate streaming.
What is Video Resolution?
Simply put, video resolution measures the width by the height of a video. Pixels are the unit of measurement used here.
For example, a video that is 1920×1080 would be 1920 pixels wide and 1080 pixels tall. The resolution is often referred to by only the height, so somebody might say that the resolution of a video with these dimensions is 1080p.
In a perfect world scenario, higher resolution equates to higher quality. However, this is not the optimal quality. As we discussed before, when viewers have slow internet, lagging and buffering become an issue.
If your viewers do not have consistently strong wifi, streaming in a lower resolution may be necessary for an optimal viewing experience.
What Does “FPS” Mean?
While it is not as important as bitrate or resolution, the frame rate is another notable tenet of video aspect ratios for live video streaming. Frame rate is measured in FPS, which stands for “frames per second.”
Frame rate is relevant to live streaming in situations where broadcasters want to effectively capture motion and quick movements. This is extremely important for sports live streams or live broadcasted concerts.
Live broadcasts that use WEBRTC technology such as webinars, training sessions, and other events where the subjects are more still don’t require crazy high frame rates.
If you are creating content to upload for on-demand consumption, you’ll want to use high frame rates if you use slow motion and other cinematic effects.
Comparing Bitrate vs. Resolution
When it comes to bitrate and resolution, it is not an either/or situation. The two go hand-in-hand. From the definitions alone, you can see that bitrate and resolution are two totally different measures. Comparing one to the other in terms of importance is impossible.
The two measure different aspects of video files. Bitrate refers to speed and file size, and resolution refers to width and height in pixels.
Bitrate and resolution can be set in different combinations to yield different qualities of video.
Popular Bitrate and Resolution Setting Combinations
There are five popular video qualities to consider when configuring your bitrate and resolutions settings. They range from ultra-low definition to full high definition.
|Name||Ultra-Low Definition||Low Definition||Standard Definition||High Definition||Full High Definition|
|Video Bitrate (kbps)||350||350 – 800||800 – 1200||1200 – 1900||1900 – 4500|
|Resolution Width (px)||426||640||854||1280||1920|
|Resolution Height (px)||240||360||480||720||1080|
Other Required Encoding Settings for Dacast
In order to achieve the optimal bitrate and resolution, it is important to properly configure your encoder.
|VIDEO CODEC||H.264 (x264 may work)|
|FRAME RATE||25 or 30|
|KEYFRAME INTERVAL||2 secs (or 2x frame rate)|
|ENCODING BITRATE||Constant (CBR)|
|AUDIO BITRATE||128 kbps|
|AUDIO CHANNELS||2 (Stereo)|
|AUDIO SAMPLE RATE||48 kHz (48,000 Hz|
As we’ve covered, bitrate and resolution are two measures that go hand-in-hand in live streaming. Bitrate measures the speed of transfer based on the file size and resolution measures the width by height in pixels.
These are two settings to pay close attention to while configuring your encoder settings for live streaming so that you end up with the video quality that you’re aiming for.
In addition to resolution and bitrate, it is important to take some time to understand other encoder settings and encoding methods. Once you get a grasp on this side of streaming, you’ll be prepared to conduct professional live streams and upload high-quality on-demand video content.
Want to see these settings in action on a professional live streaming service? Access all of the powerful features, by signing up for Dacast today to start a 30 day, risk-free trial.
For additional broadcasting tips and updates in the world of live streaming, please feel free to join Dacast’s community LinkedIn group. This group is a great place for Dacast users to connect with experts in the live streaming industry.
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