What is Bitrate and why is Audio Bitrate so Important?

Audio is surprisingly more complex than most people realize. When it comes to listening to your favorite music, audiobooks, or podcasts, or watching your favorite videos you don’t usually think about how important the sound quality is unless something is so muffled you can’t understand what’s going on.

Most people just load up YouTube, Spotify, Netflix, or their favorite audio or video service provider and click play without understanding bitrate, or how important it is to the enjoyment of the content you’re listening to. In this article I’d like to answer two questions. The first: What is bitrate? And the second: Why is bitrate so important?

Table of Contents

1. What is Audio Bitrate?
2. Commonly Used Bitrates:
3. How Is Audio Stored?
4. What is Video Bitrate?
5. Final Thoughts

What is Audio Bitrate?

When talking about audio and audio quality, the question of "What is bitrate?" inevitably comes up. And the answer differs differs whether you’re talking about audio bitrate or video bitrate.

Audio bitrate is the metric used to determine the amount of data that’s transmitted per second when it comes to audio content being delivered through playback. The amount of data being transmitted is generally measured in terms of bits, which are a commonly used method of representing memory when it comes to file storage. The specific types of measurement are megabits (mbps) and kilobits (kbps).

Having a high bitrate is important when it comes to audio playback because when the bitrate of the audio is high, there is more data being processed. When more data is being processed, listeners are able to hear a much fuller soundscape than they would be able to otherwise.

A good comparison to this would be listening to audio through a pair of speakers, then listening to the same audio with a pair of headphones on. With the speakers, you’re able to hear the audio just fine and enjoy it. But when you wear a pair of headphones or earbuds, especially if they’re capable of sound isolation, you’re able to pick up on more nuances in the audio, and hear things as the audio engineer intended them to be heard.

For example, audiobooks like those published by Graphic Audio have sound effects to make them more cinematic, listening to them with headphones would give you a better ability to hear the crunching of hooves, clanging of swords, and shouts of orders in the background of a heated battle scene.

Wearing headphones can enhance your ability to hear and enjoy those sound effects. And a higher audio bitrate makes them more enjoyable because you’re able to clearly understand and differentiate between them, compared to listening to audio that’s at a lower bitrate and sounds muffled in comparison. The clanging of swords could sound dull instead of sharp and vibrant, dialogue between characters could be drowned out, and special effects can go unnoticed when listening to a low bitrate audio file.

There are different types of audio bitrate. Constant bitrate (CBR), and variable bitrate (VBR). CBR is a bitrate that’s fixed, meaning the amount of data being processed is exactly the same throughout the playback of the entire audio file.

CBR is commonly used, but often isn’t looked upon very favorably because with a fixed bitrate there is only so much wiggle room for audio engineers to play with. When audio engineers are limited by the amount of data they have on offer, it’s difficult for them to create compelling audio details, which can lead to lower quality audio.

VBR in comparison is preferred by many audio engineers and audio listeners that call themselves audiophiles because VBR allows for the bitrate of the audio in question to be adjusted dynamically.

For example, when listening to an audiobook, if there is a scene where two characters are simply engaging in dialogue the bitrate can be lower because it’s not necessary to have an extremely high bitrate with so little going on.

But in a fast paced action scene where explosions are going off and orders are being shouted, or a musical crescendo is taking place, the bitrate can adjust dynamically and raise as high as it needs to go to produce a high quality of sound that has a more complex and dynamic range.

Commonly Used Bitrates:

There are a number of different bitrates that are commonly used.

The most common bitrates are 128 kbps, 192 kbps and 320 kbps. Those bitrates are often used for music, so when you’re listening to music on Spotify or YouTube, it’s likely playing at one of those bitrates.

Higher bitrates are also available such as 512 kbps and 1,024 kbps, which are typically for things such as audiobooks and podcasts where the creators want to offer the highest quality audio experience possible to their listeners.

How Is Audio Stored?

Audio is stored, or encoded in different file formats such as MP3, WAV, and FLAC, and they all have their own pros and cons.

MP3 files are typically smaller but they are compressed to make them small, and that compression causes the audio to lose some of its quality and robustness.

WAV files have a high degree of quality, but they are typically very large.

FLAC is typically seen as the best choice for audio listeners because it allows for audio files such as an audiobook to be compressed down into a smaller size without losing any of the quality. Audiobooks can be dozens of gigabytes in size depending on how large the book is, and depending on how much content you consume, storage can be an issue. So having a file format like FLAC that allows listeners to have higher quality audio in a smaller package is typically seen as a godsend.

What is Video Bitrate?

Similarly to audio bitrate, video bitrate is also measured in either kilobits or megabits. However instead of determining the quality of the audio, video bitrate determines the picture quality of the video being displayed. Video bitrate is responsible for the resolution of the video being watched, the frame rate of that video, and how detailed the image is.

4K resolution is extremely popular today because of its vibrant and clear images that produce a great viewing experience, as such, it requires an extremely high bitrate compared to a resolution like 480P which is extremely low quality and doesn’t have much visual detail. 4K resolution allows you to notice all of the little visual details in a scene that can stand out, such as the environmental design of the room the scene is taking place in, or the costume design of the actors in that scene.

Final Thoughts:

I hope through this article that I've been able to answer the question of "What is bitrate?" It turns out there’s a lot more that goes into consuming our favorite audio and video content than most people know.

Compression of files is extremely common because audiobooks and 4K media files can be extremely large due to the high amount of data packed into them. So clever engineers have found ways to make file smaller while maintaining their quality. But also give people who have large amounts the space the option to have the full files should they choose to. Regardless, the world of audio and video content is expansive, and I hope that next time you consume your favorite media you’ll think about the bitrate of the content you’re enjoying and appreciate the hard work that went into bringing it to you.