H.264 or AVC

Definition: H.264, also widely known as Advanced Video Coding, is a standard video compression that is used to compress or decompress a large digital video file.

What is H.264?

H.264, or Advanced Video Coding (AVC), is a standard codec used all over the world; in fact, it is one of the most preferred codecs used in video production and live streaming. H.264 is widely used because it delivers good video quality at low bitrates. H.264 provides a range of resolutions and frame rates, making it a good choice for live streaming, internet broadcasting, and video conferencing.

For instance, whenever you create a video, it’s always in a large file, often referred to as a raw file. For this example, let’s assume the size of your video file is 5 GB, uploading a raw video file itself is the problem; uploading a 5 GB video takes a ton of time.

Uploading this video feels like watching the paint dry, and the troubles continue even after the agonizing wait.

Large files can lead to slow loading times for users, particularly in instances where they need to download or stream the content. So, what to do? Edit or cut the video and let go of the important aspects of it. That’s an option for sure, but another option is to compress the file.

Compression involves reducing the size of a file by removing unnecessary data, and the tool responsible for compression and decompression is known as a codec. The term "codec" is derived from the fusion of the words compression and decompression. With the help of video codecs, video files are converted to different formats, so the video is compatible with different browsers and formats.

How does the H.264 codec work?

Using H.264 compression can compress video without compromising the quality while making the video half its original size. For example, if you have a video of 100 MB, compressing it can make the video less than 50 MB. How much of the size you can reduce highly depends on bitrate, resolution, frame rate, content complexity, and encoding settings.

The H.264 codec has three important steps: prediction, transformation, and encoding. Understanding the process with text might not provide a clear understanding, so to make things easier for us, let's understand H.264 better with pictures.

Suppose this is a scene from your video:

When we look at a frame, this is what we see, but there are tiny blocks called pixels that build the frame. Just like in the picture below:

This 16 x16-pixel block is a macroblock; H.264 creates the prediction of the macroblock. It could utilize information previously encoded within the current frame; a technique known as "intra-prediction."

Alternatively, the procedure may involve data from frames that were encoded and transmitted earlier, referred to as"interpretation."

The next step is the transformation process, a mathematical algorithm that further compresses the data, deleting the less important information while preserving the overall quality.

On the receiving end, the device decodes the compressed data, effectively reversing the compression steps to recreate the original video frame.

Is H.264 widely compatible?

H.264 is the most preferred codec, as it is compatible with almost all devices. H264 supports the latest Windows and the oldest iPhone; it might not support the Nokia keypad phone, but we can deal with that.

Because of its large compatibility, H.264 can be used in a variety of applications, including network, low and high bitrate, high resolution or low resolution, high-definition video, broadcast, and storage.

Because of this wide range of compatibility, H.264 is used in streaming, as viewers can stream from any device, browser, or network connection.