AVC (H.264) has powered internet video for over a decade, from YouTube clips to full-length streams. It’s reliable, widely supported, and still the default for many platforms.
But in 2025, where 4K is table stakes and 8K is on the roadmap, file size and bandwidth costs are back in focus. That’s where HEVC (H.265) steps in. It delivers the same quality as AVC at nearly 50% smaller bitrates, making it ideal for high-resolution streaming, mobile playback, and global delivery where every MB counts.
Still, it’s not a simple upgrade. HEVC comes with trade-offs, from device support to licensing complexity. Here’s what developers need to know.
What are AVC (H.264) and HEVC (H.265)?
AVC (also called H.264) and HEVC (also called H.265 – the newer, younger version of H.264) are standards for compressing videos used in digital recording and distribution. AVC and HEVC are both algorithms used for reducing the file size of video content while maintaining high quality, making it easier to store and transmit data across various platforms.
So, what exactly is “compression” and why do we need H.264 or H.265? The answer lies in the sheer size of raw video data generated during production.
Still confused? Let’s break it down with a quick calculation:
Let’s take Full HD video with a resolution of 1920 x 1080, 32 bits per pixel (8 bits per channel for R, G, B, and an alpha channel), at 60 frames per second.
Bits per frame: 1920 * 1080 * 32 = 66,355,200 bits
Bits per second (at 60 fps): 66,355,200 * 60 = 3,998,131,200 bits
File size for 10 seconds of footage at 60 fps:3,998,131,200 * 10 = 39,981,312,000 bits = 4,997,664,000 bytes, or approximately 4,746.1 MB (~4.7 GB).
That’s almost4.8 GB for just 10 secondsof footage, without considering the audio. Such file sizes aren’t practical for online streaming, irrespective of your network bandwidth.
To tackle this problem, we compress our footage using software or hardware codecs, which perform the mathematical operations outlined by compression standards. This process enables us to attain an appropriate quality-to-size ratio before sending content to viewers in small, easy-to-handle segments.
Compression is an important step for both on-demand and live streaming. It ensures that viewers enjoy a smooth experience without overwhelming bandwidth limitations. Now, let’s explore the two most prominent compression methods: AVC and HEVC.
What is AVC (H.264)?
Advanced Video Coding (AVC), also known as H.264, is a video compression standard developed in the year 2003. AVC is the most universally used codec. It works well on various devices, from smartphones to high-end broadcasting equipment, suitable for applications like online streaming, broadcast TV, video conferencing, and surveillance.
Despite the introduction of newer codecs like H.265 and AV1, AVC remains relevant due to its balance of compression efficiency and video quality. Many streaming services and broadcasting networks continue to rely on H.264, ensuring its continued prominence in the industry.
H.264 has seen several versions since its initial release. The main ones are:
- Baseline profile: Designed for low-complexity applications, like video conferencing.
- Main profile: Offers better compression and quality, suitable for standard-definition broadcast.
- High profile: Provides the best quality and is commonly used for Blu-ray discs and HD broadcasts.
- High ten profile: An extension that supports 10-bit color depth, improving color representation.
- High 422 profile: Supports 4:2:2 chroma subsampling, often used in professional video editing.
How Does AVC (H.264) Work?
First, each video frame is segmented into a grid of pixel blocks, referred to as macroblocks. Areas with less detail are larger, set at 16x16 matrix, while regions with more detail can be resized to 8x8 or 4x4 matrices.
Next, the codec identifies similarities among macroblocks in two ways:
- Within the same frame: It utilizes the similarities in brightness (luminance) and color (chrominance) of macroblocks, addressing spatial redundancy.
- Across previous or neighboring frames: It uses motion vectors to estimate how objects move on the screen, which tackles temporal redundancy by comparing the current frame with earlier and later frames.
These identified similarities are then grouped for compression. As a result, the data between keyframes is significantly reduced, leading to a smaller overall video file size.
Strengths of AVC (H.264)
- High compression efficiency: AVC can reduce the bitrate needed for a given level of visual quality by about 50% without losing any quality. AVC also supports adaptive streaming, adjusting video quality based on internet speed to ensure smooth playback. This allows for longer playback time on devices with limited storage.
- Broad compatibility: The codec is broadly compatible, functioning smoothly across different platforms like Windows, macOS, iOS, and Android. It is also usable on a wide range of devices, from basic smartphones to professional cameras. Moreover, AVC is supported by major editing and playback software, which simplifies easy video for users.
- Global standard: As an established standard, AVC benefits from extensive resources, including plenty of tutorials and forums available for learning and troubleshooting.
Limitations of AVC (H.264)
- Encoding time and power consumption: AVC encoding comes with some notable challenges. Longer encoding times can be a drawback for projects that need a quick turnaround. Increased power consumption can also affect battery life on mobile devices during playback or recording. Additionally, lower-end devices may struggle with dropped frames and reduced playback quality due to the computational load.
- Efficiency for high resolutions: AVC’s efficiency can fall short of 4K and higher resolutions. As video quality increases, AVC often requires higher bit rates to maintain quality, leading to larger file sizes. This can be a concern for media companies, as larger files increase storage costs and can be less suitable for bandwidth-limited scenarios.
- Higher latency: Latency can be a problem for AVC in real-time applications. The complexity of its encoding and decoding processes may introduce delays, which can hinder live streaming or video conferencing. Additionally, variable network conditions can lead to buffering issues, negatively impacting the user experience.
- Licensing and futureproofing: While AVC’s licensing fees are generally lower than HEVC’s, there are still costs associated with commercial use. The licensing process can be complex, which may lead to unexpected expenses. Furthermore, as video technology evolves, AVC may struggle to meet the demands of newer, more efficient codecs, putting content providers at risk of obsolescence.
Developer tips for AVC (H.264)
Keep your AVC projects efficient and user-friendly. Prioritize compatibility to reach a wider audience by ensuring your videos work on various devices. Test your encoding settings to find the right balance between quality and performance. Finally, always monitor user experience to identify and resolve any playback issues quickly.
- Prioritize compatibility: Use AVC in applications where broad compatibility is essential. It works well across many devices and platforms, including older hardware, ensuring users can access content without issues. This makes AVC a reliable choice for content aimed at a diverse audience. Plus, its widespread support helps avoid problems related to playback and user experience.
- Focus on real-time performance: Implement AVC for real-time applications like video conferencing and live streaming. Low latency and quick processing are crucial for a smooth user experience in these scenarios. By prioritizing AVC, developers can enhance the quality of real-time interactions and ensure that users enjoy seamless communication. This approach also helps in minimizing delays that can disrupt conversations or streams.
- Optimize encoding settings: Adjust encoding parameters such as bitrate and keyframe intervals to balance quality and performance. Each use case may require different settings to ensure smooth playback without compromising visual quality. By fine-tuning these parameters, developers can achieve optimal results tailored to specific needs. This flexibility allows for better performance, especially in varying network conditions.
- Utilize hardware acceleration: Use hardware encoders and decoders, such as Intel Quick Sync Video or NVIDIA NVENC. These tools offload processing from the CPU, which can significantly improve performance and reduce latency. Utilizing hardware acceleration also helps maintain high-quality video without overloading system resources. This is particularly useful in resource-intensive applications, ensuring a smoother experience for users.
