Video Codecs Explained: H.264 vs H.265 vs VP9 vs AV1

Introduction: Why Video Codecs Matter More Than You Think

Every time you press play on a video -- whether it is a YouTube tutorial, an Instagram Reel, or a movie on Netflix -- a codec is doing the invisible heavy lifting behind the scenes. The codec determines how large the file is, how good it looks, how fast it loads, and whether it even plays on your device at all. Choose the wrong codec and you could end up with a file that is bloated, blurry, incompatible, or all three.

Yet most people never think about codecs. They think about formats -- MP4, WebM, MOV -- without realizing that the format is just the container, and the codec inside is what actually matters. It is the difference between caring about the label on a shipping box and caring about what is packed inside it.

This guide breaks down the four codecs that dominate the video landscape in 2026: H.264, H.265 (HEVC), VP9, and AV1. You will learn where each one excels, where it falls short, and which one you should use for your specific situation. If you are looking for a broader view of container formats, the best video formats comparison for 2024 covers MP4, WebM, MKV, and other containers in detail.

Codecs at a Glance: Quick Comparison Table

Before diving into the details, here is a high-level comparison so you can orient yourself quickly.

Understanding Video Codecs: The Fundamentals

What Is a Codec?

The word "codec" is a portmanteau of "coder-decoder." A codec is an algorithm that compresses raw video data into a compact format for storage or transmission (encoding) and then decompresses it for playback (decoding). Without codecs, a single minute of uncompressed 1080p video would consume roughly 10 GB of storage. Codecs make video files manageable by finding and eliminating redundant information.

Codec vs. Container: A Critical Distinction

The container -- MP4, WebM, MKV, MOV -- is the file format that wraps video, audio, subtitles, and metadata into a single package. The codec is the compression algorithm used for the actual video stream inside that container. An MP4 file might contain H.264, H.265, or AV1 video -- the container is the same, but the codec determines compression efficiency, quality, and compatibility.

This distinction matters practically. When someone says "convert to MP4," they are specifying a container but leaving the codec unspecified. That is why the MP4 converter at ConvertIntoMP4 lets you select both the output format and the encoding settings.

Lossy vs. Lossless Compression

All four codecs in this guide primarily operate as lossy compressors, permanently discarding visual information your eyes are unlikely to notice -- subtle color gradients, high-frequency noise, and redundant data between consecutive frames. Lossless compression preserves every bit but produces files far too large for streaming or sharing.

For streaming, social media, and web delivery, lossy compression with well-chosen settings is the right approach. If you want practical guidance on dialing in those settings, the guide to compressing video online walks you through the process step by step.

How Modern Codecs Compress Video

Modern video codecs combine several techniques:

• Spatial compression (intra-frame): Removes redundancy within each individual frame, similar to how JPEG compresses a photo.
• Temporal compression (inter-frame): Compares consecutive frames and stores only the differences. In a talking-head video where 90% of the frame stays still, this is extraordinarily effective.
• Transform coding: Converts spatial data into frequency domain representations, allowing the encoder to discard high-frequency details that contribute little to perceived quality.
• Entropy coding: Applies lossless mathematical compression to squeeze out remaining statistical redundancy.

Newer codecs improve on H.264 by using larger block structures, more sophisticated prediction modes, and better entropy coding -- which is why they achieve dramatically better compression at the same quality level.

H.264 (AVC): The Universal Standard

H.264 (Advanced Video Coding) was finalized in 2003 and has been the dominant video codec for over two decades. It divides each frame into 16x16 pixel macroblocks and introduced innovations like variable block sizes, multiple reference frames, and Context-Adaptive Binary Arithmetic Coding (CABAC) that delivered roughly double the efficiency of MPEG-2.

Strengths: Universal compatibility across every device, browser, and platform in existence. Two decades of hardware optimization mean encoding and decoding are fast and power-efficient. Every video editing application and streaming platform supports it natively.

Weaknesses: Produces larger files than newer codecs at the same quality -- a 100 MB H.264 file could be 50-60 MB in H.265. Limited HDR support. The 16x16 macroblock ceiling limits further efficiency gains.

Licensing: Patent-encumbered through MPEG LA, but terms are well-established and baked into consumer hardware and software costs. Free for internet video that is free to end users.

Where it is used: Blu-ray discs, most social media platforms, video conferencing (Zoom, Teams), HDTV broadcasting, and the majority of web video. If you want to understand how H.264 fits into the MOV vs. MP4 debate, the MP4 vs MOV format comparison covers the practical differences.

H.265 (HEVC): The Efficient Successor

H.265 (High Efficiency Video Coding) was finalized in 2013 with one primary goal: deliver the same visual quality as H.264 at roughly half the bitrate. It achieves this through Coding Tree Units up to 64x64 pixels (versus H.264's 16x16), 35 intra-prediction modes, improved motion prediction, and more efficient entropy coding. The result is a consistent 40-50% bitrate reduction over H.264 at equivalent perceived quality.

Strengths: Dramatically better compression makes it ideal for 4K and 8K content. Native support for HDR10, HDR10+, and Dolby Vision. The codec of choice for UHD Blu-rays and most 4K streaming services. Growing hardware support on devices manufactured after 2017.

Weaknesses: Complex licensing involving multiple patent pools (MPEG LA, HEVC Advance, Velos Media) has created legal uncertainty that keeps Chrome and Firefox from shipping H.265 decoding. Encoding takes 2-10x longer than H.264. Poor fit for web video where browser support gaps matter.

Where it is used: UHD Blu-rays, satellite and cable 4K TV, Apple's ecosystem (iPhones record in HEVC by default), and streaming services' 4K and HDR tiers.

VP9: Google's Open-Source Challenger

VP9 was developed by Google and released in 2013 as a royalty-free, open-source alternative to H.265. It uses superblocks up to 64x64 pixels with recursive subdivision, achieving compression efficiency roughly on par with H.265 -- typically within 5-10% for most content types.

Strengths: Completely royalty-free with no patent licensing fees. Excellent browser support in Chrome, Firefox, Edge, and Opera. YouTube encodes and delivers the majority of its library in VP9, giving it massive real-world deployment. Delivers 30-50% better compression than H.264.

Weaknesses: Encoding with the reference libvpx encoder is notoriously slow. Limited hardware encode support compared to H.264 or H.265. Less adoption outside the web -- rare in broadcast or consumer electronics. Apple has historically been slow to support VP9 in Safari, though recent versions on Apple Silicon have improved.

Where it is used: YouTube video delivery, Google services (Meet, Stadia), and web video embedding. If you are producing content for the web, the WebM converter at ConvertIntoMP4 makes VP9/WebM conversion straightforward.

AV1: The Future of Video

AV1 was released in 2018 by the Alliance for Open Media (AOMedia), a consortium including Amazon, Apple, Google, Intel, Meta, Microsoft, Mozilla, Netflix, Nvidia, and Samsung. Its goals were explicit: surpass H.265 and VP9 in compression efficiency while remaining royalty-free forever.

AV1 uses 128x128 pixel superblocks, film grain synthesis (removing grain during encoding and re-synthesizing during decoding to save bitrate), warped motion compensation for non-translational motion, and up to 7 reference frames. The result is approximately 30% better compression than H.265 and over 50% better than H.264.

Strengths: Best-in-class compression efficiency, unmatched in quality-per-bit. Completely royalty-free with industry-wide backing. Native HDR10 and HDR10+ support. Growing browser support across Chrome, Firefox, Edge, Opera, and recent Safari versions.

Weaknesses: Software encoding remains very slow -- 5-50x slower than H.264 depending on the encoder. Hardware encode is available on recent GPUs (Nvidia RTX 40+, AMD RDNA 3+, Intel Arc, Apple M4+) but the installed base is still small. Older devices cannot decode AV1 at all.

Where it is used: YouTube and Netflix are actively rolling out AV1 for hardware-capable devices. The web is adopting AV1 for both video and images (AVIF format). Adoption is accelerating but not yet universal.

Detailed Comparison: Head to Head

Compression Efficiency with Real-World File Sizes

Here is what you can expect encoding the same 1-minute, 1080p 30fps source clip at visually equivalent quality:

The CRF values differ between codecs because each uses a different scale. These values are calibrated for approximately equivalent perceptual quality.

Quality, Speed, and Hardware

When you force all four codecs to the same bitrate (say, 4 Mbps for 1080p), the quality hierarchy is: AV1 (cleanest) > H.265 > VP9 > H.264. The differences are most visible in challenging content -- fast motion, fine textures, dark scenes. At higher bitrates (10+ Mbps), all four codecs produce excellent results and differences narrow significantly.

Encoding speed follows the inverse pattern. H.264 typically encodes 1080p at 2-5x real-time. H.265 is 2-5x slower than H.264. VP9 is 3-10x slower. AV1 (using SVT-AV1) is 5-15x slower. The trade-off is clear: better compression costs more encoding time.

For hardware acceleration, H.264 has universal encode/decode support on every device made in the last 15 years. H.265 hardware decode is standard from 2017 onward. VP9 hardware decode covers most devices from 2018 onward. AV1 hardware decode is available on chips from 2022 onward (Intel 11th gen+, Nvidia RTX 30+, AMD RDNA 2+, Apple M3+).

Browser and Device Compatibility

This is the table to reference when choosing a codec for web distribution.

The pattern is clear: H.264 is the only codec with truly universal support. H.265 has gaps in Chrome and Firefox. VP9 covers the web but has Apple ecosystem gaps. AV1 is the most capable but still expanding across older device categories.

Licensing and Cost

• H.264: Royalty-based through MPEG LA. Costs are baked into devices and software. Free for internet video that is free to viewers.
• H.265: Complex multi-pool royalties (MPEG LA, HEVC Advance, Velos Media, plus independent holders). This complexity is the primary barrier to web adoption.
• VP9: Royalty-free, open-source. No licensing costs.
• AV1: Royalty-free with AOMedia patent license. Backed by a defensive patent pool.

The licensing landscape is the single biggest reason VP9 and AV1 have gained traction despite H.265's technical head start.

Which Codec Should You Use?

For Social Media and General Sharing

Use H.264 in an MP4 container. This combination plays on every device and platform. When you email a video or upload to Instagram, Facebook, TikTok, or LinkedIn, H.264/MP4 is the safest choice. For platform-specific guidance, the best video format for social media in 2026 covers each platform's settings.

For 4K Streaming and Storage

Use H.265 (HEVC). The 40-50% file size reduction over H.264 is particularly valuable at 4K, where bitrates would otherwise balloon. Ideal when your audience is on modern devices in the Apple or smart TV ecosystems.

For Web Video Embedding

Use VP9 in a WebM container with H.264/MP4 as fallback. VP9/WebM gives excellent compression and broad browser support. Pair it with H.264/MP4 for Safari and older browsers. The WebM converter handles VP9 encoding for you.

For YouTube and Video Platforms

Upload in the highest quality you can. Platforms re-encode into VP9 and AV1 automatically. Your job is to provide the best source material -- do not pre-compress aggressively.

For Archiving

Use H.265 or AV1 in an MKV container. Compression efficiency is king for storing terabytes of footage. AV1 gives the best ratio; H.265 offers a good compromise with faster encoding.

For Live Streaming

Use H.264 or H.265 with hardware encoding. Real-time encoding rules out VP9 and AV1 for most setups. H.264 with NVENC or Quick Sync is the most reliable choice.

How to Convert Between Codecs

Maybe you have an H.265 video that will not play in Chrome, or you need to convert iPhone MOV files to WebM for your website. The video converter at ConvertIntoMP4 handles all these scenarios with no software to install.

Common conversion workflows:

• H.265 to H.264: For maximum compatibility. Use the MP4 converter with H.264 encoding.
• H.264 to VP9/WebM: For optimized web delivery. Use the WebM converter.
• MOV to MP4: The most common Apple-to-universal conversion. The MOV converter streamlines this.
• Any format to MP4: For universal compatibility. The video converter accepts virtually any input.

For detailed compression settings, the guide to compressing video online covers bitrate, resolution, and quality recommendations for every scenario.

Frequently Asked Questions

What is the difference between a codec and a video format?

A video format (or container) is the file type that wraps video, audio, and metadata together -- MP4, WebM, MKV, MOV. A codec is the compression algorithm for the video stream inside that container. An MP4 file can contain H.264, H.265, or AV1 video -- same container, different codec. The codec determines compression efficiency and compatibility; the container determines what types of streams can be included. For a comparison of containers, see the best video formats 2024 guide.

Is AV1 better than H.265?

In compression efficiency, yes -- AV1 achieves about 30% better compression at equivalent quality and is royalty-free. However, H.265 has faster encoding speed, broader hardware support on older devices, and deeper integration in broadcast and consumer electronics. AV1 is technically superior in 2026, but H.265 remains the practical choice when you need fast encoding or must target pre-2021 devices.

Can I play AV1 video on my phone?

Most Android phones from 2020 onward with Snapdragon 888+, Dimensity 1000+, or Exynos 2100+ include hardware AV1 decoding. For iPhones, AV1 decode is available on the iPhone 15 Pro and later (A17 Pro chip). Older devices may software-decode AV1 but with poor battery life and potentially choppy playback. Always provide an H.264 fallback if your audience includes older devices.

Why does YouTube use VP9 instead of H.265?

Licensing. VP9 is royalty-free, so Google can encode and serve video to billions of viewers without per-device royalties. H.265's complex licensing would cost enormously at YouTube's scale. VP9 offers competitive compression, so there is no meaningful quality sacrifice. YouTube is also transitioning to AV1 for newer content, continuing the royalty-free approach.

Should I re-encode my existing video library in a newer codec?

Generally, no. Re-encoding is lossy -- each decode-and-re-encode cycle permanently loses some quality. An H.264 file re-encoded to AV1 will be smaller but will never look better than the original. Re-encoding makes sense only if you need to cut storage costs on a large library, need to change codecs for compatibility (like H.265 to H.264 for browsers), or have access to original uncompressed sources.

What is the best codec for video calls?

H.264 is the most widely used in conferencing (Zoom, Teams, Google Meet) due to universal hardware acceleration and low latency. VP9 appears in Google Meet for higher-quality modes. AV1 is emerging in conferencing for its scalable video coding capabilities. Your conferencing app handles codec selection automatically -- this is not a choice you typically need to make.

How do I check which codec a video file uses?

In VLC Media Player, right-click your video during playback and select "Media Information" or "Codec Information." On macOS, select the file in Finder and press Cmd+I. On Windows, right-click the file, select Properties, and check the Details tab. For the most detail, use FFmpeg's ffprobe tool in the terminal. Knowing your source codec helps you decide whether and how to convert.

Conclusion

The codec landscape in 2026 follows a clear trajectory: each generation delivers better compression, but adoption takes time. H.264 remains the universal fallback. H.265 excels for 4K and HDR content but is held back by licensing on the web. VP9 dominates as the royalty-free web standard through YouTube. AV1 represents the future with the best compression and royalty-free licensing, limited only by encoding speed and hardware adoption pace.

Your choice should be driven by your specific use case -- your audience's devices, your distribution channel, and your encoding constraints -- not by which codec is newest.

When you are ready to convert or experiment with different codecs, the video converter at ConvertIntoMP4 supports every format and codec covered in this guide. Upload your video, choose your settings, and download the result -- no installation required.