Video Codecs Explained: H.264 vs H.265 vs AV1 for Streaming

Video codecs determine how efficiently video is compressed, directly impacting quality, file size, and compatibility. Choosing the right codec is critical for streaming platforms balancing quality, bandwidth costs, and device support.

Codec Overview

H.264 (AVC - Advanced Video Coding)

Release: 2003

Licensing: Patented, requires MPEG-LA license fees

Status: Industry standard with universal support

H.264 revolutionized video streaming by providing good compression with reasonable encoding complexity. It remains the most compatible codec across devices, browsers, and platforms.

H.265 (HEVC - High Efficiency Video Coding)

Release: 2013

Licensing: Complex patent pools (MPEG-LA, HEVC Advance, Velos Media)

Status: Growing adoption, especially for 4K content

H.265 offers 25-50% better compression than H.264 at equivalent quality, but complex licensing and slower adoption have limited its reach.

AV1 (AOMedia Video 1)

Release: 2018

Licensing: Royalty-free (Alliance for Open Media)

Status: Rising adoption, considered future standard

AV1 provides best-in-class compression (30-50% better than H.264) with no licensing fees. Major tech companies (Google, Apple, Amazon, Netflix, Meta) are members of the Alliance for Open Media.

Compression Efficiency Comparison

CodecBitrate for 1080pBitrate for 4KEfficiency vs H.264 H.2645-8 Mbps15-25 MbpsBaseline H.2653-5 Mbps10-15 Mbps25-50% better AV12-4 Mbps8-12 Mbps30-50% better

Real-World Example

For a 4K video at similar perceptual quality:

H.264: 20 Mbps file size
H.265: 12 Mbps (40% bandwidth savings)
AV1: 10 Mbps (50% bandwidth savings)

These savings translate directly to reduced CDN costs and better playback on slower connections.

Browser Support (2025)

CodecChromeFirefoxSafariEdge H.264FullFullFullFull H.265Hardware onlyHardware onlyApple Silicon onlyHardware only AV1FullFullNoneFull

Key Compatibility Notes

H.264: Works everywhere, including older devices, smart TVs, and set-top boxes.

H.265: Browser support requires hardware acceleration. Safari only supports H.265 on Macs with Apple Silicon chips. Many smart TVs and streaming devices do support H.265.

AV1: Growing browser support but Safari notably absent. Hardware decoder availability expanding with newer CPUs and GPUs.

Encoding Complexity and Speed

CodecEncoding SpeedCPU UsageHardware Encoders H.264FastLowNVENC, QSV, VCE, VideoToolbox H.265MediumMediumNVENC, QSV, VCE, VideoToolbox AV1SlowHighNVENC (RTX 40+), QSV (Arc), limited

Encoding Time Comparison

For a 1-hour 1080p video on modern hardware:

H.264 (libx264): 15-30 minutes
H.265 (libx265): 30-60 minutes
AV1 (libaom): 2-6 hours
AV1 (SVT-AV1): 45-90 minutes (faster encoder)

Hardware Encoding Options

NVIDIA NVENC: Excellent H.264/H.265 support. AV1 encoding on RTX 40 series and newer.

Intel Quick Sync Video: Good H.264/H.265 support. AV1 on Intel Arc GPUs.

AMD VCE: H.264/H.265 support. AV1 on RX 7000 series.

Apple VideoToolbox: H.264/H.265 on Apple Silicon with excellent efficiency.

FFmpeg Encoding Commands

H.264 Encoding (libx264)

For high-quality H.264 with CRF (Constant Rate Factor) mode, use the libx264 encoder with CRF value around 23 and medium preset. Lower CRF means higher quality and larger files.

H.265 Encoding (libx265)

For H.265, use libx265 encoder with CRF around 28 (roughly equivalent quality to H.264 CRF 23) and medium preset.

AV1 Encoding (SVT-AV1)

For AV1, SVT-AV1 is recommended for better speed. Use CRF around 30 and preset 6 for good balance of speed and quality.

Use Case Recommendations

Use CaseRecommended CodecReason Maximum compatibilityH.264Universal device support Bandwidth optimizationH.26540% smaller files, good device support Future-proofingAV1Best compression, royalty-free Live streamingH.264 or H.265Fast encoding required VOD archivesAV1Encode once, save bandwidth forever Mobile-firstH.264Battery efficiency, compatibility Smart TV appsH.265Good support, 4K common

Multi-Codec Delivery Strategy

Modern streaming platforms serve multiple codecs to optimize for each viewer:

Detection Flow:

1. Check browser/device codec capabilities

2. Serve AV1 to supported browsers (best compression)

3. Fall back to H.265 for compatible devices

4. Default to H.264 for universal support

5. Use adaptive bitrate within each codec

Implementation Benefits:

Bandwidth savings of 20-40% on average
Better quality for capable devices
Maintained compatibility for all viewers

Licensing Considerations

H.264 Licensing

MPEG-LA administers patent pool
Free for internet video that is free to end users
Commercial use requires licensing

H.265 Licensing

Multiple patent pools (complex)
Higher licensing costs than H.264
Licensing uncertainty has slowed adoption

AV1 Licensing

Royalty-free
Alliance for Open Media members
Patent protection fund for users
Clear advantage for commercial streaming

Quality Metrics

When comparing codecs at equivalent bitrates, use objective metrics:

PSNR (Peak Signal-to-Noise Ratio): Traditional metric, higher is better.

SSIM (Structural Similarity Index): Better correlation with human perception.

VMAF (Video Multi-Method Assessment Fusion): Netflix-developed, best correlation with subjective quality. Scores 0-100, with 93+ considered excellent.

Conclusion

Choose H.264 when:

Maximum compatibility is priority
Encoding speed is critical
Older device support needed

Choose H.265 when:

4K content delivery
Bandwidth costs are significant
Audience uses modern devices

Choose AV1 when:

Future-proofing library
Royalty-free licensing required
Willing to invest in encoding time

For most streaming platforms, a multi-codec strategy delivers the best results: AV1 where supported, H.265 as fallback, H.264 as universal baseline.

Platforms like dcast.tv handle multi-codec encoding and delivery automatically, optimizing quality and bandwidth for each viewer without manual configuration.