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What is Video Encoding? Overview of Video Compression Technology

8 min read
What is video encoding

Video streaming technology is widely used to deliver video content over the Internet. The popularity of streaming services has driven the demand for higher quality video files at lower bit rates. In order to meet this demand, video encoding technology has evolved to use compression algorithms that reduce the size of video files while preserving their visual quality.

But do you want to know what video encoding is and why it matters? This article will explore the concept of the video encoding process, video codecs, and the overview of video file compression techniques. This includes the use of recommended codecs, although it depends. We will also describe how different encoding parameters can affect a compressed video stream’s final output video quality and file size.

What is Video Encoding?

It’s a video compression technique used to reduce the size of raw video files without degrading their visual quality. Video encoding compresses and potentially reformat video files. Video encoding aims to produce a compressed video stream indistinguishable from the source video file. A video encoder can accomplish this by using a codec.

Video Encoding

Video encoder compresses raw video content into a compressed video stream with the help of encoding parameters.

In a single word, video encoding compresses raw video files into digital video files. The process involves encoding parameters that can affect file size and video quality.

What is the Importance of Encoding?

The main benefit of using a good video encoder software is producing files that are both small in size and high in quality. This is especially important for streaming, where internet bandwidth is weak.

In addition, proper encoding can help reduce buffering problems and improve playback performance. By using the proper codecs and encoding parameters, you can ensure that your viewers will have a smooth viewing experience without waiting long for videos to load. That improves engagement with the audience and their satisfaction.

Video encoding is important for two reasons now. The first, especially related to streaming, facilitates video transfer over the Internet. This is because compression reduces the required bandwidth while providing a high-quality experience. Without this reduction of video size, raw video content would make it impossible for many people to stream video due to low internet speed. The important aspect is the bitrate or the amount of data per second in the video. This will determine if they can easily view the content or get caught up in the buffered video for streaming.

The second reason for video encoding is compatibility. Content has sometimes been compressed to a sufficient size. But the encoding is still required for compatibility, although this is often more precisely described as transcoding. Compatibility may involve certain services or programs that mandate certain encoding specifications. It may also include increased compatibility with viewer playback.

The video codec or video compression standard determines the video encoding process.

Does Video Encoding Reduce Quality?

The answer to this question is a little more complicated than a simple yes or no. Three factors typically determine the quality of a compressed video stream:

  • The codec
  • Encoding parameters &
  • Source video file.

Codecs are software that compresses and decompresses digital videos. There are many different codecs available, each with its strengths and weaknesses. Some codecs are better at preserving visual quality while reducing file size.

Encoding parameters are settings that control the way of video compression. These settings can affect the quality of the final compressed video stream. For example, the bitrate parameter determines how much data is used to encode each second of video. In general, increasing the bitrate will produce a higher quality compressed video stream. However, there are times when encoding parameters can be adjusted to reduce file size without sacrificing too much visual fidelity. Overall, it’s better to use a good codec at maintaining quality than to try and save on encoding settings.

The final factor that affects video quality is the source video file itself. Some videos are better suited for compression than others. Videos with high resolution can be more challenging to compress without sacrificing quality. Conversely, you can compress videos with lower resolution more without affecting quality.

What is Video Decoding?

The video decoding process reverses the encoding process. The video decoder accepts compressed data as input and produces uncompressed data. In video streaming technology, the different types of video players play the role of a video decoder.

Video players receive the encoded compressed video stream as input and decode them into raw videos.

Most of the time, web browsers play streaming content by using built-in media players or third-party plugins that act like decoders. The plugin determines which codec to use depending on the encoding parameters it receives from a streaming server.

Without the decoding process, you cannot view any graphical content streamed over the Internet! That’s why both encoding & decoding are essential for online video sharing technologies.

What is a Video Codec?

A codec (compression-decompression) is software or hardware are that helps encode and decode digital video files. It compresses two components of a video file- audio & video. The most used video codecs are H.264, H.265, MPEG-4, DivX, and audio codecs- AAC, ALAC, AMR, FLAC.

Video codecs

Video codecs are video compression standards achieved through software or hardware applications. The naming codec combines these concepts into one word: Encoder and Decoder. A codec includes a video encoder to compress the video and a decoder for recreating an approximation of video for playback.

These codes should not be confused with the containers used to encapsulate everything. MKV (Matroska Video), MOV (short for MOVie), AVI (Audio Video Interleave), and other types of files are examples of these container formats. These containers do not define how to encode and decode video data.

Instead, they store codec bytes so that compatible applications can play the content. Furthermore, these containers store video and audio information and metadata. However, this can be not very clear because some audio codecs have the same name as the file container, such as FLAC.

What is the best video codec?

This is a question that cannot be answered directly without more information. The reason is that different video codecs are best for a different atmosphere.

H.264 has become a standard video codec for high-quality video streaming. The codecs are of excellent quality, coding speed, and compression efficiency. However, they are not as efficient as the later HEVC (High-Efficiency Video Coding, also known as H.265) compression standards. H.264 can also support 4K video streaming.

However, as mentioned above, HEVC (H.265) has provided a more advanced video compression standard. This codec is more efficient in compression, allowing more people to watch high-quality videos on slower internet connections.

Although this codec failed to move the world, it was improved, and a new codec called VP9. Netflix tested these later formats compared to H.264. They found that both codecs could reduce the bitrate by 50% and achieve similar quality to H.264. In both, HEVC is superior to VP9 in many resolutions and quality indicators. The exception is 1080p resolution, which is close to or makes VP9 more effective in some cases.

Doesn’t this make HEVC or H265 the best codec with these tests? Although technically superior to H.264, it ignores a key advantage of older codecs: compatibility. H.264 is widely supported by various devices. Only iPhone can support HEVC, where most devices support H.264. Therefore, although not as advanced, H.264 is still favored in many cases to reach a wider audience for playback.

Note that the H.264 codec is sometimes called X.264. However, this is not the same codec but is a free equivalent of a licensed H.264 codec and implementation.

What is the best audio codec?

Like the video, there are different audio codecs in different respects: AAC (Advanced Audio Coding) and MP3 (MPEG-1 Audio Layer 3) are two lossy formats widely known. Since they are lossy, these formats strip out audio-related information to compress the required space. The effect of this compression is to strike the right balance, saving enough space without significantly affecting audio quality.

These two audio encoding methods have been around for a while. MP3 was originally introduced in 1993, compared to the uncompressed standard size of audio files. Reduced to 10%, AAC was first released in 1997. As a later format, AAC may not be surprising. Compress audio quality of AAC is more smooth and efficient.

Nowadays, MP3 has more device compatibility. On the other hand, AAC benefits from superior compression and is the preferred method of streaming video content. Not only that, but most of the video-related streaming relies on the AAC audio codec. An example is IBM Cloud Video, although audio can be transcoded as needed to meet these specifications.

AAC and MP3 are far from the only formats for digital audio. Many other lossy like WMA (Windows Media Audio) and lossless like APAC (Apple Lossless Audio Codec) are also popular in the multimedia world. One such format is FLAC (Free Lossless Audio Codec), which is lossless- means the original audio data can be perfectly reconstructed from the compressed data. Although the audio track size is smaller than WAV (Waveform Audio File Format), an uncompressed format, it still requires more streaming audio data than lossy formats like AAC and MP3.

Audio and Video Codecs that Castr Recommends for Live Streaming

Castr uses advanced streaming technology to provide fast and efficient live video streaming services. We recommend AAC audio codecs and H.264 video codec for live streaming. For more information on how to set up your encoding software, please see our blog post on How to Live Stream with Castr.


It can be summed up that understanding different video codecs is important for live streaming. If you stream your video content to multiple devices, pay attention to what codecs they support and how much bandwidth the network requires before deciding on your encoding settings. Proper research makes it possible to provide high-quality videos while still reaching a wide audience with low enough requirements so that people can still enjoy watching them from anywhere in the world at any time! Thanks for reading!

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