What are Codecs?

What are Codecs?

Like a fish needs water to survive, live streaming video (and audio) needs codecs to function. But what exactly is a codec? Let’s start at the beginning.

Raw video is created by displaying a series of still images in rapid succession. Unfortunately, storing those images in their original form takes up a lot of space. The higher the quality (or bitrate) of your video, the more storage and bandwidth you’ll need. That’s where codecs come in.

The Definition of a Video Codec

A codec—short for compressor-decompressor or coder-decoder—uses an encoder to compress video files by removing redundant data. This compression is essential for storing, transferring, and streaming video efficiently without overwhelming bandwidth or storage resources.

Once compressed, the file is sent to a decoder, which decompresses it and plays it back as smooth, high-quality video. This entire process, especially when done in real-time, requires serious computational power—which is why the efficiency of your codec matters.

What Are the Different Types of Codecs?

There are several types of codecs, including:

Lossly vs. Lossy Codecs

Codecs fall into two categories:

What is the H.264 Codec?

H.264 is the most commonly used codec in live streaming today. It strikes a balance between quality and file size, making it ideal for web streaming. It’s also universally supported across modern devices, which is why it remains the default choice for most streaming platforms—even though newer, more efficient codecs are available.

What is H.265?

H.265, or HEVC, builds on H.264 and offers up to 50% better compression with the same visual quality. It supports resolutions up to 8K, but it lacks full compatibility across some browsers—particularly Chrome and Firefox.

What is AV1?

AV1 is the newest open-source codec developed by the Alliance for Open Media, with backing from major tech players like Amazon, Google, Microsoft, Netflix, and Facebook. It delivers up to 50% better compression than H.264, and up to 30% better than H.265, making it one of the most efficient options available today.

AV1 is designed for modern and future devices, offering long-term compatibility and streaming efficiency. And while it’s been used by platforms like YouTube and Netflix, it’s now accessible to churches and ministries as well—through Resi.

Open-Source Codecs

There are two, open-source video codecs available. The VP9 codec was developed by Google and the AV1 codec was created by the Alliance for Open Media. So far, only big-name companies such as Amazon, Facebook, YouTube, and Netflix have adopted these codecs.

AV1 Is Now Available for Resi Multisite

Resi now supports AV1 for Multisite streaming, giving churches access to higher-quality video with significantly reduced bandwidth demands.

To use AV1 with Resi, you’ll need:

AV1 is included at no extra cost in every Resi Multisite plan. No complicated setup. No new workflows. Just dramatically more efficient streaming with the tools you already trust.

What Codecs Does Resi Use?

Resi supports H.264, H.265, and AV1 streaming codecs, which are saved as presets within Resi Studio Depending on the streaming environment, different codecs are recommended.

With the addition of AV1, Resi continues to lead the way in reliable, high-performance streaming for churches—combining cutting-edge technology with real-world usability.