It’s undeniable that creating high-quality video content is essential for businesses of all sizes. Videos are used across social media for marketing and for advertising. They’re a key way to convey complex topics in a way that’s easier to understand, and they make a big impression. 

With this increasing need for quality videos, it’s important to learn some of the technical elements that come with video optimization and quality. 

One such term to get familiar with is codec, which is discussed more below. 

The Basics

A codec is something combining two words—coder and decoder. A codec can be software or hardware based. 

A codec isn’t a video format, and one analogy that can help with understanding it’s this—a codec is the language of a letter. The format is the envelope the letter goes in. Codecs can live in different formats, with formats being represented by the extension of your video file, like .mov or .mp4. 

A codec is a way to compress video information that’s in a video file. 

If you were to alternatively define the color of each pixel in a video, the file size would be huge. 

That’s hard to deal with, so computer scientists created codecs to reduce file sizes. 

The reason for codecs is they make it easier to transfer massive video files over the internet. To speed up the downloads, there are algorithms that can encode or shrink them, which is a signal for the actual transmission. Then, it can be decoded for editing or viewing. If you didn’t have codecs, it would take three to five times longer to download videos and audio compared to now. 

Codec Examples

Determining which codec is best depends on your purpose. 

Animation is a lossless codec, so there’s no decline in quality. It’s a codec typically only for 2D or 3D animation or for special effects. For live action, it doesn’t work well because it’s not reductive of file sizes. 

H.264 was a game-changer when it was first introduced in 2003, with the primary codec before its introduction being Sorenson. H.264 led to improvements in compression and picture quality. A lot of the video you watch online currently uses this codec. 

ProRes is Apple-branded, and it was initially created for use with Final Cut Pro, but even after that end of that, it remains in use. 

Uncompressed 8-bit or 10-bit is actually compressed with Chrome Sub-Sampling, and it’s used for editing. 

How They Work

Codecs use various techniques for the reduction of file sizes. 

With run-length encoding, if you have a big part of your video image that’s the same color, it’s not best to repeat the color information for all the pixels in the frame. Instead, it makes more sense to say a pixel is a certain color and the rest of the pixels are as well. This method is categorized as lossless, which means that no picture quality is lost. 

In the video, eight bits are typically used for color definition, and that leads to gradations of color. If you wanted to have more definition, then you could apply 10 bits to the color of all the pixels, which is what 10-bit Uncompressed video does. 

Eyes are naturally sensitive to brightness but not as much to color, so with Chroma sub-sampling, you can retain brightness but get rid of some of the color information. 

The best codec for a project is going to depend on the purpose of your content and the hardware you use because different codes are re-used for shooting and editing, as well as animation and special effects. There are also distinct codecs for purposes of streaming and archival purposes. 

What is the Bit Rate?

Finally, within the discussion of codecs is another term to be aware of, which is the bit rate. This is a measure of how much a codec compresses a video clip. Bit rate is usually expressed as a data amount per second. 

If you had a codec with outputs at 8 Mbps, that would then give you a file that was eight megabits large for each second of video. 

Bit rates aren’t the same as quality. 

There are codecs that can deliver outstanding image quality at the same bit rate that would produce poor quality in older codecs. 

If you’re rendering a video, your codec will ask you the bit rate you want for your output, and you want to choose one that’s going to give you the best image quality with the smallest file sizes. Larger bit rates usually only give small improvements, but lower bit rates can deteriorate your image fast.