Video Codec - Everything You Need To Know

Definition

A video codec is a technology that plays a crucial role in digital video processing, primarily used to compress (encode) and decompress (decode) video data. This compression is vital for reducing file sizes and bandwidth requirements, making video storage and streaming more efficient. Video codecs operate by applying complex algorithms to eliminate redundant or unnecessary data, striking a balance between maintaining video quality and achieving high compression efficiency.

What does it really mean?

Imagine a video codec as a skilled artist tasked with creating a miniature replica of a large, detailed painting. This artist's goal is to capture the essence and key details of the original painting but on a much smaller canvas. In doing so, the artist carefully decides which elements are crucial to retain the painting's overall look and feel, and which minor details can be omitted without significantly altering the viewer's experience. The process of deciding what to keep and what to remove is similar to how a video codec compresses video data—retaining essential information (key visual elements) while discarding data that won't be greatly missed (minute details). Just as different artists have their own styles and techniques (like the various types of codecs, H.264, HEVC, etc.), each codec has a unique way of balancing quality and size to effectively shrink the "canvas" of the video while maintaining its visual integrity.

History of Video Codec

1970s: Emergence of Audio Codecs

• The journey began in the 1970s with the development of the first audio codec, G.711, by the International Telecommunication Union (ITU).
• Designed for telephony networks, G.711 was a pioneering technology with a bit rate of 64 kbps, setting the standard for voice audio compression and transmission.

1988: The First Commercially Successful Video Codec

• The ITU made a significant leap in video technology by introducing the H.261 video codec in 1988.
• Tailored for video conferencing, H.261 offered a resolution of 352×288 pixels at a frame rate of 30 frames per second, marking a milestone in video compression and transmission for commercial applications.

1990s: The Rise of MPEG Standards

• The Motion Picture Experts Group (MPEG) then took center stage in the 1990s, developing a series of video coding standards that became globally dominant.
• MPEG-1, introduced in 1993 for use in CD (VCD) players, provided a resolution of 352×240 pixels at 30 frames per second, enabling higher quality video on digital mediums.
• MPEG-2 followed, designed for DVD players. It maintained the frame rate but improved the resolution to 720×480 pixels, enhancing video quality for home entertainment.

2000s and Beyond: Advancements and Wide Adoption

• The most transformative development in recent times has been the H.264/MPEG-4 AVC codec, introduced in the mid-2000s and becoming the most widely used video codec since 2016.
• H.264/MPEG-4 AVC stands out for its versatility and efficiency, being used in a plethora of applications from video recording to streaming, offering high-quality video compression suitable for various platforms and devices.

How Video Codec Works?

A codec encapsulates the essential processes of data transformation for both video and audio, serving as a bridge between raw media content and its transmission across networks, as well as its final consumption. The codec's journey begins with the original media — raw video footage and its original sound. These elements are first processed separately; the video through a video codec and the audio through an audio codec. The codecs apply sophisticated algorithms to encode and compress the data, reducing file sizes by eliminating redundant information and optimizing the data stream for transmission.

Once compressed, the audio and video streams are combined or encapsulated into a single video file format, ensuring that they remain synchronized. This file is then ready for storage or transmission across data networks, taking up less bandwidth and space than the original content. At the reception end, the process reverses. The same or compatible codec decodes and decompresses the video file, turning the compacted byte sequence back into audio and video streams. During this stage, the codec reconstructs the data to a state as close to the original as possible, balancing the inherent loss from compression with the need for efficient transmission.

The final step is the playback, where the decompressed audio and video are presented in unison, delivering a seamless viewing experience. This entire process demonstrates the codec's role in managing the delicate trade-off between maintaining quality and achieving compression. Different codecs offer a spectrum of outcomes, from smaller file sizes with reasonably acceptable quality to higher-quality files that are larger and may be more challenging to edit. This versatility is particularly evident in modern devices like smartphones, which come equipped with optimized hardware to support various video codecs, ensuring that users can create, share, and consume media with ease and high fidelity. The history and evolution of codecs, from G.711 and H.261 to the more advanced H.264/MPEG-4 AVC, reflect the ongoing advancement in codec technology, shaping how we experience digital media today.

Difference between Video Codecs and Video Containers?

A video container, also known as a container format, serves as a "wrapper" or "holder" for various types of data related to multimedia. Essentially, it's a file format that contains and organizes video, audio, subtitles, and any other metadata into a single file structure. The container determines how these different data streams are stored and interlinked, ensuring they play back in sync.

The video container doesn't affect the quality of the video or audio, as it does not compress or manipulate the data streams itself; that's the job of the codecs. Instead, the container format defines how the streams are packaged together and interact with playback devices or software. For instance, an MP4 file is a popular container format that can hold video and audio compressed by codecs such as H.264/MPEG-4 AVC for video and AAC or MP3 for audio.

The versatility of a video container lies in its ability to support multiple codecs for video and audio streams, allowing users to choose the best codecs for their needs and have them encapsulated within a single, manageable file. This flexibility makes video containers integral to multimedia distribution, as they offer a standardized way to deliver complex media content across various platforms and devices.

Most Common Video Formats

H.264/AVC (Advanced Video Coding)

Also known as MPEG-4 Part 10, H.264 has been one of the most commonly used formats for video compression.

Pros:

• Offers good video quality at relatively low bit rates, making it widely compatible and efficient.
• It's used in everything from Blu-Ray discs to web video streaming services due to its flexibility and support for resolutions up to 8K.

Cons:

• While it's highly efficient, newer codecs have surpassed it in terms of compression capability and performance at very high resolutions.

H.265/HEVC (High Efficiency Video Coding)

This successor to H.264 doubles the data compression ratio at the same level of video quality or substantially improves video quality at the same bit rate.

Pros:

• Supports resolutions up to 8192×4320, including 8K UHD.
• Increased efficiency makes it suitable for streaming high-quality video over the internet, especially where bandwidth may be limited.

Cons:

• More complex to encode, requiring more computing power, which can be a drawback for devices with limited processing capabilities.
• Licensing and royalty issues have complicated its adoption to some extent.

AV1 (AOMedia Video 1)

Developed by the Alliance for Open Media, AV1 is an open, royalty-free video coding format designed for video transmissions over the internet.

Pros:

• Higher compression efficiency compared to H.264 and H.265, offering better quality at the same bit rate, which is particularly beneficial for 4K and higher resolutions.
• Strong backing by major software and hardware companies, with increasing support across browsers and platforms.

Cons:

• As a newer codec, it's still gaining ground in terms of widespread hardware support and may require more processing power for encoding and decoding compared to older codecs.

### VP9

Developed by Google as a successor to VP8, VP9 is an open-source codec designed primarily for use with Google's video services, like YouTube.

Pros:

• Offers a significant reduction in file size at the same quality level as H.264, making it very efficient for streaming high-resolution video.
• Being open-source, it's free to use without licensing fees, encouraging adoption.

Cons:

• Similar to AV1, it requires more computational power for encoding, which can be a challenge for real-time encoding scenarios or on less powerful devices.

H.266/VVC (Versatile Video Coding)

The latest standard in the H.26x series, H.266/VVC, is designed to provide efficient video compression for a wide range of applications from low-end mobile streaming to high-end 8K broadcasting.

Pros:

• Offers a significant improvement in compression over H.265/HEVC, claiming to halve the data requirements for high-quality video streaming.
• It is designed to be versatile, handling everything from 360-degree video to screen content and still images within video streams.

Cons:

• As with many new technologies, the complexity of the encoding process is higher, which can impact the resources required for real-time applications.
• Adoption is still in the early stages, and it may face similar licensing and royalty challenges as its predecessors.

Frequently Asked Questions

Which video codec is best?

The "best" video codec depends on the specific requirements of usage: H.264/AVC is widely adopted and offers good compatibility, H.265/HEVC provides better compression and is suited for high-resolution video, while AV1 is gaining traction for its royalty-free status and superior compression, making it ideal for future web video.

Which is better 264 or 265?

H.265 (HEVC) is generally better than H.264 (AVC) in terms of compression efficiency, offering about double the data compression at the same level of video quality, which makes it more suitable for high-resolution video like 4K and 8K. However, H.264 has wider compatibility with existing devices. It requires less computational power to encode and decode, making it more practical for lower-end hardware or applications where device compatibility and power consumption are crucial.

Which video codec is the fastest?

H.264/AVC is typically the fastest in terms of encoding and decoding speeds due to its simpler algorithms and widespread hardware acceleration support across devices, making it very efficient for real-time applications like video conferencing and streaming with lower computational overhead.

References

• https://www.britannica.com/technology/codec
• https://en.wikipedia.org/wiki/Codec
• https://api.video/blog/video-trends/the-history-of-video-compression-starts-in-192