The Difference Between Bitrate, Resolution, and Frame Rate (and Why It Matters When Streaming Video)

The Difference Between Bitrate, Resolution, and Frame Rate (and Why It Matters When Streaming Video)
Photo: Tero Vesalainen, Shutterstock

When you fire up a video on reputable streaming services like Netflix or HBO Max, you don’t have to think much about it; you just press play and enjoy. However, if you are (ahem) pirating that video, you might notice that you have a variety of video options to choose from: Bitrate, resolution, and frame rate. What are these options, and how do they differ? (Not that you would ever need to know, I’m sure.)

You might have some idea already; when you adjust these options, the quality of your video stream changes. If you lower the quality, the stream might perform better, too, especially if you have a slower internet connection. But knowing the difference between frame rate, bitrate, and resolution (especially the latter two) can help you fine-tune the quality of your stream to best suit your internet connection and your TV or screen.

Frame rate

Let’s start with something simple: frame rate. All video is a collection of individual images, or frames. Frame rate refers to the speed at which those frames are arranged to create video, usually per second (fps). Standard frame rates include 24 fps (film and some TV), 30 fps (mainstream TV), and 60 fps (internet content).

It’s best to try to match the frame rate of the source file when streaming content online. In many cases, the video player will show that to you, or won’t even give you the option to change it. The major exception is with 60 fps — this high frame rate is typically reserved for online content, rather than traditional film and TV shows. When someone uploads a 60 fps video file to the streaming service, you often have the choice to stream it in that native frame rate, or to drop it down to a more manageable 30 fps.

If your internet speeds can handle it, streaming natively is always best. However, if things are having trouble chugging along, frame rate is something you can reduce. Since you’re cutting the number of frames in the stream, it can reduce lagging and buffering. However, it will also result in a jittery image. You might want to start with the following two options instead.

Bitrate

A video’s bitrate refers to the amount of data a video contains. Generally, the higher the bitrate, the higher the quality of the video, since it has more video information to work with. With video streaming, the bitrate is usually measured in megabits per second (or mbps). The higher the number, the more megabits per second the video will run.

In an ideal world, you’d want to watch a video with as high a bitrate as possible, so you don’t lose any quality (that’s partly why enthusiasts love physical media like Blu-Ray). However, the higher the bitrate, the larger the size of the video. Video is a large file format already, and it takes a lot of power to stream those large files. Even if you have internet speeds that are capable of streaming lossless video files, it’s horribly inefficient. Often, there are completely static sections of video, such as a long shot of a non-moving background, where it just doesn’t make sense to send each frame of that video one after another.

That’s where reducing a video’s bitrate comes into play. This is also known as compression, and its job is to reduce a video’s overall size by deleting video information in order to save on space. Yes, this can result in lower video quality, but not always perceived video quality. Let’s look at that static background example — if a character is moving in the foreground, the compression will save and send that part of the image. However, since the background isn’t changing, it just sends one frame, until the image changes again. It’s sneaky, but you never notice.

Of course, sometimes reducing the bitrate too much can affect the quality in a way that’s noticeable. The more you reduce bitrate, the fewer details you’ll see in your image. Still, if your stream is lagging, reducing the bitrate can be one place to look; try testing a few different bitrate options to see if you can live with the lower quality, especially if it helps the stream’s overall stability.

Before you do, however, you might want to consider the following.

Video resolution

Video resolution is often confused for bitrate; but while they both affect how a video looks, they aren’t responsible for the same thing. Resolution is the measure of how many pixels a video contains. You might be familiar with resolutions such as 1080p and 4K; 1080p video is 1,920 pixels wide and 1,080 pixels tall, while 4K video is 3,840 pixels wide and 2,160 tall.

4K video can look sharper because it contains more pixels than 1080p, or other video resolutions like 720p and 480p. When you lower the resolution of a video stream, you’re reducing the number of pixels that stream is sending to your display.

This reduction in pixels can be an effective way to boost the performance of a stream when your internet connection can’t handle it, and might be preferable to lowering the bitrate. After all, if you’re trying to watch a 4K stream on a 1080p or 720p TV, you aren’t able to properly take advantage of those extra pixels.

Even if you do have a 4K TV, dropping the frame rate can be the best first step. You’d likely prefer a high bitrate 1080p video than a low bitrate 4K video; the former might not be pixel perfect to your TV, but it will contain more video information than the low bitrate 4K file, which can appear more detailed on your end.

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