What Is a Video Codec?
A codec (short for "coder-decoder") is a technology that compresses video data for transmission and decompresses it for playback. Without codecs, raw video files would be enormous — a single minute of uncompressed 4K video can exceed 100 GB. Codecs make streaming possible by dramatically reducing file sizes while preserving as much visual quality as possible.
Three codecs dominate modern video streaming: H.264 (AVC), H.265 (HEVC), and AV1. Each represents a generation of compression technology, with significant differences in efficiency, compatibility, and hardware support.
H.264 (AVC): The Universal Standard
Also known as Advanced Video Coding (AVC), H.264 has been the dominant video codec since its introduction in the mid-2000s. It is supported by virtually every device, platform, and browser in existence, making it the default choice for broad compatibility.
Key Characteristics of H.264
- Compatibility: Universal — supported on all smart TVs, browsers, phones, consoles, and streaming services.
- Hardware support: Hardware-accelerated encoding and decoding on virtually all modern CPUs, GPUs, and chips.
- Efficiency: Good but outdated compared to newer codecs — requires higher bitrates to achieve the same quality as H.265 or AV1.
- Typical use case: Live streaming to platforms (RTMP ingest), standard video delivery, older device support.
For live streaming creators, H.264 remains the safest and most widely recommended choice due to its universal platform support.
H.265 (HEVC): Twice the Efficiency
High Efficiency Video Coding (HEVC), or H.265, was designed as the successor to H.264. Its key achievement is delivering the same visual quality at roughly half the bitrate of H.264. This makes it highly valuable for 4K streaming and bandwidth-constrained delivery.
Key Characteristics of H.265
- Compression efficiency: Approximately 40–50% more efficient than H.264 at the same quality level.
- 4K and HDR support: Widely used for 4K streaming, Blu-ray, and broadcast-quality video.
- Compatibility: Good on modern devices but not as universal as H.264; some older devices and browsers lack support.
- Licensing: H.265 involves complex patent licensing, which has slowed its open adoption.
- Typical use case: 4K VOD streaming (Netflix, Disney+), broadcast delivery, storage-efficient archiving.
AV1: The Open-Source Future
AV1 was developed by the Alliance for Open Media (AOMedia) — a coalition including Google, Mozilla, Apple, Netflix, Amazon, and others — as a royalty-free, open-source alternative to H.265. It offers even better compression than H.265 and is rapidly becoming the codec of choice for large-scale streaming platforms.
Key Characteristics of AV1
- Compression efficiency: Roughly 30% more efficient than H.265 and up to 50% more efficient than H.264 at equivalent quality.
- Royalty-free: No licensing fees, enabling broader adoption by platforms and device makers.
- Compatibility: Growing rapidly — supported on Chrome, Firefox, Android, newer smart TVs, and recent GPU generations (Nvidia RTX 30/40 series, AMD RDNA 2+).
- Encoding complexity: Historically slow to encode, though hardware encoders are closing this gap quickly.
- Typical use case: YouTube, Netflix, and other large platforms streaming at scale where bandwidth savings translate to significant cost reductions.
Codec Comparison at a Glance
| Feature | H.264 (AVC) | H.265 (HEVC) | AV1 |
|---|---|---|---|
| Compression Efficiency | Baseline | ~50% better | ~50% better than H.265 |
| Device Compatibility | Universal | Good (modern devices) | Growing (newer devices) |
| Licensing | Patented | Complex patents | Royalty-free |
| Hardware Encoding | Widely available | Widely available | Newer hardware only |
| Best For | Live streaming, max compatibility | 4K VOD, broadcast | Large-scale platform delivery |
Which Codec Should You Use?
For live streamers using OBS or similar tools, H.264 is still the right default — it's universally supported by ingest platforms and has robust hardware encoder support on virtually all GPUs.
For video-on-demand content creators encoding files for web delivery, H.265 offers meaningful quality improvements at lower file sizes, especially for 4K content.
For platform operators and developers building streaming infrastructure today, AV1 is worth investing in — its royalty-free model and superior efficiency will make it the dominant codec of the next decade.