Understanding What a Video Codec Is and How It Works

If you’re in the business of streaming or content creation, video codecs are something you deal with all the time—whether you realize it or not. This is the technology that compresses video so it can stream smoothly without taking up too much space.

Understanding video codecs is key if you plan to upload videos for an audience. There’s a lot to learn and many terminologies to keep in mind, but once you’re done, you’ll be ready to stream content like a pro.

In this article, we’ll walk you through what a video codec is, how it works, and why it’s so important for delivering top-notch content. Let’s start by learning the basics!

What is a Video Codec?

A video codec is a tool used to compress and decompress video files. The term “codec” comes from combining the words “compressor” and “decompressor.” The technology essentially reduces the size of video files for easier storage and faster transmission, without losing too much quality.

The main purpose of a video codec is to make video files smaller for smooth streaming and download across the internet. Without codecs, video files would be far too large to share efficiently.

Video Codecs Throughout the Years

Video codecs have evolved significantly over the years to meet the demands of streaming and digital video. One of the first video codecs was 1990’s H.261, designed for video conferencing. MPEG-2 soon followed in 1995, for DVD use and digital television broadcasts.

Other notable codecs include:

1. H.264 (2003): A major milestone that became the standard for video streaming.
2. HEVC (H.265, 2013): The successor to H.264, HEVC provided better compression and higher quality, especially for 4K video.
3. VP9 (2013): Developed by Google, it was designed as an alternative to HEVC.
4. AV1 (2018): The newest player, AV1 is an open-source codec designed for even more efficient compression and higher quality

Codec vs. Container

When working with video files, it’s important to understand the difference between codecs and container formats. While they often work together, they serve different purposes in video processing.

Codecs: This is the technology of compressing and decompressing video files to reduce their size while maintaining quality. They determine how video data is encoded and decoded.

Containers: On the other hand, containers are like digital “wrappers” that hold both the video and audio data, along with metadata, like subtitles. A container can support multiple codecs for video and audio streams.

Containers are essential for organizing and storing video data. They bundle together video, audio, and other elements (like subtitles or chapter markers) into a single file.

Some popular container formats are: MP4, MKV, AVI, and MOV

If you’re looking to optimize the organization and streaming quality of your video data, employing advanced video analytics can help refine your strategies. 

For example, MediaMelon‘s advanced QoE analytics solutions can offer strategic insights into viewer behavior and platform performance. Based on these insights you can choose a better codec and container for your videos.

Now that you understand the basics on video codecs, let’s look at some of the common ones used today.

Popular Video Codecs Used Today

When it comes to video streaming and delivering content, a few codecs have become the go-to standards These codecs help strike the right balance between video quality, file size, and ensuring smooth playback on all kinds of devices and platforms.

1. H.264/AVC: Widely Used and Efficient

H.264 remains the most common codec used in streaming services and video platforms. It strikes a great balance between compression and quality, making it perfect for a wide range of applications, from YouTube to Netflix.

2. H.265/HEVC: Improved Efficiency and Adoption

H.265 provides superior compression compared to H.264, enabling higher video quality while significantly reducing file sizes. This makes it ideal for streaming 4K and HDR content, though it does demand more processing power for decoding.

3. AV1: Royalty-Free and Future-Ready

AV1 is the next-generation codec, designed to outperform H.265 and even VP9. It’s open-source and royalty-free, making it an attractive choice for future-proofing content delivery, especially for high-quality streaming in 4K and beyond.

We’ve covered a lot about codecs so far, but it is time to look at how they actually function. Let’s examine the compression of video codecs up next.

How Do Codecs Work?

Understanding how codecs work involves looking at the video encoding process, which is essential for compressing large video files and delivering them efficiently.

Here’s a breakdown of how codecs handle video data from start to finish:

1. The Video Encoding Processes

• The raw video file is compressed using a specific codec.
• The encoder analyzes each frame, spotting patterns and redundancies.
• The codec applies algorithms to reduce file size without sacrificing too much quality.
• The compressed video is now easier to store and stream.

2. Types of Compression: Balancing Efficiency and Quality

Different compression methods alter how data is handled, with some focusing on maximizing storage efficiency while others prioritize maintaining visual fidelity. This balance affects the codec’s ability to deliver smooth playback, which is especially important in video streaming.

Let’s take a look at the different types of compression.

1. Intraframe (Spatial) vs. Interframe (Temporal) Compression

Modern video codecs use two main techniques, intraframe and interframe compression, to reduce file sizes efficiently.

Intraframe (Spatial) Compression: This method compresses individual video frames by reducing redundancies within a single frame. It looks at the pixels and groups them to minimize data. Think of it like compressing a single image.

Interframe (Temporal) Compression: Instead of focusing on each individual frame, interframe compression works across multiple frames. It identifies similarities between frames and only stores the differences (changes in pixels or objects).

This technique reduces the data required for consecutive frames and is crucial for compressing long video sequences efficiently.

2. Lossy vs Lossless Compression

While video compression varies based on many factors, the process can be divided into two broad categories: lossy and lossless. Each has its own benefits and certain drawbacks.

Lossy Compression: Lossy compression reduces file size by discarding some of the video data, typically details that the human eye might not notice. This leads to a significant reduction in size but at the cost of some quality loss.

Popular codecs like H.264 and H.265 use lossy compression to keep video files manageable for streaming. While the quality loss is often minimal, highly compressed videos may show signs of pixelation or blurriness, especially at lower bitrates or on larger screens.

Lossless Compression: Lossless compression preserves all the original video data, meaning no quality is lost during compression. It’s perfect for situations where maintaining video quality is critical, like professional video editing or archiving.

The trade-off, however, is that lossless video files are much larger compared to lossy ones, making them less practical for streaming or large-scale distribution.

Lossless compression is often used for short-term storage or when videos need to be edited or processed multiple times without losing quality.

3. Video Decoding and Viewing

Once a compressed video reaches a streaming device, it needs to be decoded for viewing. The decoder uses the same codec that was used to encode the video, reversing the compression process and rebuilding the video data.

This happens in real-time, allowing users to watch the video smoothly with minimal delay or buffering.

We’ve covered a lot of important points about video codecs, their types and compressions. Now, it’s time to look at what aspects you need to consider, when choosing the right codec for your content.

Choosing the Right Codec

When selecting the best video codec for your needs, several factors come into play. The right codec depends on your goals, whether it’s for streaming, editing, or storing video files.

Here’s what to keep in mind:

1. Compatibility

Ensure the codec you choose is compatible with the devices and platforms where your video will be viewed or shared. For instance, H.264 is widely supported across many devices, while newer codecs like AV1 may not yet be universally compatible.

2. Balance Between File Size and Video Quality

Finding the right balance is key. Higher compression typically leads to smaller file sizes but can affect video quality. Consider how much quality you’re willing to sacrifice for a smaller file size, especially when streaming high-definition or 4K content.

Codecs like H.264, H.265 reduce file sizes by up to 50% or more while maintaining similar video quality. AV1 provides excellent compression, achieving higher quality at smaller file sizes, especially for 4K and HDR content.

3. Licensing and Cost Considerations

Some codecs come with licensing fees, such as H.265/HEVC, which may add costs for using or distributing video. On the other hand, open-source codecs like AV1 are royalty-free and more budget-friendly. Although, they might require more processing power for encoding and decoding.

With that, we’ve covered video codecs in detail. If you’ve followed through, you should have a much better understanding of video compression and decompression, and should already have a type of video codec in mind for your next project.

To ensure you’re making the best decisions for your platform, consider using video analytics. MediaMelon’s state-of-the-art QoE solution provides in-depth data on viewer behavior, allowing you to optimize codec selection and deliver the best possible streaming experience.

If not, let’s look at some final thoughts, before we wrap up.

Conclusion

Video codecs might sound complicated at first, but it’s really not that hard to wrap your mind around. If you work with video creation and streaming, it’s crucial that you know this technology inside and out.

As the demand for high-quality video content continues to rise, codecs like H.264, H.265, and AV1 are paving the way for efficient and high-performance streaming. Looking ahead, we can expect continued innovation in video codec technology, especially as 4K, 8K, and HDR content become more common.

If you’re in the market for a leading video analytics provider, look no further than MediaMelon. Our state-of-the-art QoE analytics solutions give you an in-depth look at viewer Quality of Experience and offer valuable intel on viewer behavior. With data-driven insights, you can cultivate a loyal consumer base and unlock higher NPS, ad revenue, and user engagement.

Book a demo with our video experts to see how MediaMelon can be tailored to meet your OTT platform’s unique needs and deliver powerful results in action.