H.264 (AVC): Advantages and Disadvantages

This article explores the pros and cons of H.264 (AVC), also known as Advanced Video Coding. It details the benefits and drawbacks of this widely used video compression standard.

Introduction

A video codec consists of two main components: an encoder and a decoder.

• The video encoder converts analog video into a compressed digital format. This reduces file sizes, making it easier to stream video over the internet, in real-time, or on-demand. Video encoding also helps minimize buffering requirements.
• Both video and audio codecs are used to compress raw video and audio files.

What is H.264?

H.264 is a video compression standard introduced in 2003 by the ITU-T video coding experts group and the ISO/IEC moving picture experts group. It’s also known as MPEG-4 Part 10.

This video codec standard is widely used across smartphones, tablets, computers, and streaming media players. It employs techniques such as intra-frame prediction, inter-frame prediction, and entropy coding to compress video. It offers a high level of compression with good video quality and is commonly used in Blu-ray discs, broadcast TV, and video streaming.

Here are some key features of H.264 (AVC):

• Encodes high-resolution video up to 4K and supports HD (High Definition) video up to 1080p resolution.
• Offers improved error resilience for a more consistent and reliable video playback experience.
• Enhanced motion estimation with various block sizes, supporting prediction block sizes like 4x4, 8x8, and 16x16, and 9 modes for intra prediction.
• Supports 59.94 fps.
• Supports CABAC and CAVLC entropy coding.
• Uses a hybrid compression model.
• Supports different profiles such as baseline, main, and extended.
• Supports advanced intra-coding, multiple reference pictures, integer block transform, and improved de-blocking filters.

The figure depicts H.264 video encoder modules and video decoder modules.

Benefits of H.264 (AVC)

Here are the advantages of using H.264 (AVC):

• High Quality at Low Data Rates: Produces high-quality video at lower data rates compared to previous standards.
• Efficient Compression: Compresses video files to half the size of its predecessor, MPEG-2, while maintaining the same quality. This reduces storage requirements and facilitates easy video transmission through IP networks.
• Fast Encoding and Decoding: Enables fast and efficient video encoding and decoding with the help of multi-core CPUs. It’s twice as efficient as the MPEG-2 codec.
• Low Latency: Offers low-latency video encoding/decoding, resulting in fast response times and minimal delays in real-time applications.
• Bandwidth Efficiency: Provides high-quality images with minimal bandwidth usage.
• Excellent for Slow Motion: Extremely efficient for slow-motion video content.

Disadvantages of H.264 (AVC)

Here are the drawbacks of using H.264 (AVC):

• Costly Implementation: Can be expensive to implement due to patent licensing fees compared to other video codecs.
• Complexity: It’s a complex video codec requiring many parameters to be configured for specific applications.
• Processing Power: Demands significant processing power for encoding/decoding, which is a challenge for devices with limited processing capabilities.
• Limited Resolution Support: Does not natively support video resolutions higher than 4K. Additionally, it lacks native support for HDR (High Dynamic Range) video.
• Reduced Compression with Error Resiliency: The error resiliency feature helps mitigate bit errors but can lead to lower compression rates.