Video Codecs: H.264 vs H.265 vs AV1 Explained 2026

Last updated: · By WatchlyGuide Team

A video codec is software that compresses video so it is small enough to stream, then decompresses it for playback — “codec” is short for coder-decoder. The three that matter for streaming are H.264 (AVC), H.265 (HEVC) and AV1: each newer generation squeezes the same picture into less data, but demands newer hardware to decode. This guide compares them on efficiency, quality, device support and battery, and explains which to use when.

Three file sizes shrinking left to right labelled H.264, H.265 and AV1 at the same picture quality
Each codec generation delivers the same quality in less data — at the cost of newer hardware.
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What a Codec Does

Raw video is enormous — a few seconds of uncompressed 4K can be gigabytes. A codec makes it streamable by removing redundancy: areas of the picture that do not change between frames are not re-sent, and fine detail the eye barely notices is simplified. The amount of data kept per second is the bitrate.

Two things about a codec matter for you:

  • Efficiency — how much quality it keeps per megabit. More efficient codecs look better on a slow connection.
  • Decoding — your device must be able to decode the codec, ideally in dedicated hardware. Without it, playback falls back to the CPU, which drains battery and can stutter.

H.264 (AVC)

H.264, also called AVC, is the veteran. Released in 2003, it is supported by virtually every screen, browser and streaming device made since.

  • Efficiency: the baseline everything else is measured against.
  • Support: universal — the safest choice for compatibility.
  • Best for: reliable playback everywhere, up to 1080p; older devices.
  • Trade-off: needs roughly double the bitrate of H.265 for the same 4K quality.

H.265 (HEVC)

H.265, or HEVC, is H.264’s successor and roughly 40–50% more efficient — the same quality at about half the bitrate. That efficiency is what makes practical 4K and HDR streaming possible.

  • Efficiency: about 2× better than H.264.
  • Support: most devices from the last several years, but not all browsers.
  • Best for: 4K and HDR on modern hardware.
  • Trade-off: patent-licensing complexity, which slowed its adoption on the open web.

AV1

AV1 is the newest of the three, created by the Alliance for Open Media (Google, Netflix, Amazon and others). It is royalty-free and about 20–30% more efficient than H.265.

  • Efficiency: the best of the three, especially at low bitrates.
  • Support: only recent devices decode it in hardware; older ones fall back to power-hungry software decoding.
  • Best for: efficient streaming to modern devices with no licensing cost.
  • Trade-off: heavy to encode, and rough on older hardware’s battery.

Why big services love AV1: being royalty-free and highly efficient, it cuts both bandwidth bills and licensing fees — which is why YouTube and Netflix stream AV1 to devices that support it and fall back to H.264 for the rest.

Bar chart comparing relative bitrate needed by H.264, H.265 and AV1 for the same 4K quality
Relative bitrate for the same 4K quality: AV1 needs the least, H.264 the most.

Side-by-Side Comparison

Codec Released Efficiency vs H.264 Device support Royalty-free?
H.264 (AVC) 2003 Baseline Universal No
H.265 (HEVC) 2013 ~40–50% better Broad, modern devices No
AV1 2018 ~50–60% better Recent devices only Yes

Which to Use

You rarely pick a codec by hand — services choose it and negotiate with your device. But the logic is:

  • Need it to play anywhere? H.264.
  • Streaming 4K/HDR to a modern TV or box? H.265.
  • Want top efficiency on recent hardware, no royalties? AV1.

If a 4K stream stutters or your device runs hot, an unsupported codec forcing software decoding is a common cause — a newer streaming device with hardware AV1/HEVC decoding fixes it.

The Bottom Line

Codecs are the compression engine of streaming. H.264 is the universal baseline, H.265 roughly halves the bitrate for practical 4K and HDR, and AV1 pushes efficiency further while being royalty-free — provided your hardware can decode it. Newer is more efficient but demands newer silicon, which is exactly why services send the best codec each device can handle and fall back to H.264 for everything else.

Next, see how compression translates to picture quality in our guides to bitrate, resolution and HDR.

Not sure about a term on this page? Look it up in the streaming glossary.

Frequently Asked Questions

What is a video codec?

A video codec is software that compresses video for storage or streaming and decompresses it for playback. 'Codec' means coder-decoder. It removes redundant data — parts of the image that repeat between frames — so a huge raw video becomes small enough to stream, with little visible quality loss.

What is the difference between H.264 and H.265?

H.265 (HEVC) is the successor to H.264 (AVC) and is roughly 40–50% more efficient, so it delivers the same quality at about half the bitrate, which makes it ideal for 4K and HDR. H.264 is older but supported on virtually every device, while H.265 needs newer hardware and carries licensing costs.

Is AV1 better than H.265?

AV1 is more efficient than H.265, typically saving another 20–30% bitrate for the same quality, and it is royalty-free, which is why YouTube and Netflix adopted it. Its drawbacks are heavier encoding and that only recent devices decode it in hardware. On older hardware, AV1 can drain battery or stutter.

Which codec should I use for streaming?

For maximum compatibility use H.264, which plays everywhere. For efficient 4K and HDR on modern devices use H.265 (HEVC). For the best efficiency and no royalties on recent hardware use AV1. Most large services now send AV1 or H.265 to capable devices and fall back to H.264 for older ones.

Why does codec choice affect battery life?

Decoding video costs energy. When a device has a dedicated hardware decoder for a codec, playback is efficient and cool. If it lacks one, it must decode in software using the CPU, which uses far more power, heats up and can stutter. That is why AV1 on an old phone drains the battery quickly.

Do codecs affect video quality?

Indirectly, yes. A more efficient codec preserves more quality at the same bitrate, or the same quality at a lower bitrate. So AV1 or H.265 can look better than H.264 on a limited connection. But at very high bitrates the visible differences shrink — codec efficiency matters most when bandwidth is constrained.