Video Codecs Explained: H.264, HEVC, VP9, AV1 and What They Mean for You

A codec — short for coder-decoder — is the method used to compress video so it can travel over the internet, and to decompress it on your screen. The codec decides how much detail survives at a given bitrate, how much data a stream uses, and which devices can play it at all. This guide gives you video codecs explained in plain English, with the four you’re most likely to meet.

For how codecs fit alongside protocols and containers, see streaming protocols explained.

How video compression works

Raw video is enormous. Codecs make it manageable by:

• Removing repetition between frames — most of one frame looks like the last, so only the changes are stored.
• Simplifying detail the eye notices less — fine texture in fast motion, subtle colour differences.
• Predicting parts of the picture from nearby areas.

The more efficient the codec, the more it can save without visible loss. When the bitrate is too low for the content, you see artefacts: blocks in dark scenes, smeared crowds, or “mosquito noise” around edges.

The main video codecs

H.264 (AVC)

Introduced in the early 2000s and still the most widely supported codec.

• Plays on virtually every device made in the last decade or more.
• Common for HD live channels and older content.
• Less efficient than newer codecs, so 4K in H.264 needs very high bitrates.

HEVC (H.265)

The successor to H.264.

• Substantially more efficient — often described as reaching similar quality at around half the bitrate in good conditions.
• Widely used for 4K and HDR, and for some HD channels.
• Needs hardware decoding on the device; older or budget devices may struggle.

VP9

Developed by Google as a royalty-free alternative.

• Efficiency broadly comparable to HEVC.
• Used heavily by some large video platforms, especially in web browsers and on Android devices.

AV1

A newer, royalty-free codec from an industry alliance of technology and media companies.

• Highly efficient, which helps 4K and lower-bandwidth streaming.
• Increasingly used by major streaming services on devices that support it.
• Hardware support is common in newer TVs, streaming devices and phones but missing on many older ones.

On the horizon: VVC (H.266)

Standardised more recently, VVC promises further efficiency gains, but device support is still limited.

Comparison at a glance

Codec	Efficiency	Device support	Typical use
H.264	Baseline	Universal	HD live channels, older content
HEVC	Higher	Most 4K devices	4K, HDR, some HD
VP9	Higher	Browsers, Android, many TVs	Web video platforms
AV1	Highest of the four	Newer devices	Modern streaming, 4K

Hardware vs software decoding

Your device decodes video either with a dedicated hardware decoder — fast and efficient — or in software on the main processor. High-resolution HEVC or AV1 in software can overwhelm small devices, causing stutter or a black screen with sound. That’s why IPTV players offer a decoder setting, and why switching it can fix problem channels — see fixing an IPTV black screen.

Codecs, bit depth and HDR

HDR video needs 10-bit colour so gradients don’t show banding; HEVC’s Main 10 profile and AV1 support it, while most H.264 streams are 8-bit. HDR formats such as HDR10 and Dolby Vision sit on top of the codec; our guide to HDR10 vs Dolby Vision covers them.

Audio codecs in brief

Video codecs get the attention, but audio has its own: AAC for most streams, Dolby Digital (AC-3) and Dolby Digital Plus (E-AC-3) for surround sound, and Opus in some web platforms.

What codecs mean for you

• Picture quality depends on codec and bitrate — an efficient codec at a decent bitrate looks best. See IPTV streaming quality.
• Device choice matters for 4K: check HEVC and, increasingly, AV1 hardware support.
• Data usage falls as codecs improve.
• Problem channels that won’t play on an older device are often using a codec it can’t decode well — try the HD version.

How to check which codec a stream uses

Most players can show technical details while a stream is playing:

• VLC: open Tools → Codec Information to see the video and audio codecs, resolution and frame rate.
• Kodi: press the info key (or O on a keyboard) during playback to see codec and decoder details.
• IPTV players such as TiviMate or OTT Navigator often show stream information from the playback menu.
• Streaming apps sometimes offer a “stats for nerds” or diagnostics overlay.

If a channel stutters, check whether it’s HEVC or a high frame rate. Comparing codec information between a channel that works and one that doesn’t often explains the difference immediately.

Choosing devices with codecs in mind

When you buy a TV or streaming device, look for these points in the specifications:

1. HEVC (H.265) hardware decoding — essential for most 4K and HDR streams.
2. AV1 hardware decoding — increasingly used by major services; worth having on a new device.
3. VP9 support — useful for web video platforms.
4. 10-bit and HDR support — needed for HDR content to display properly.

Our guide to the best device for IPTV covers other features to compare.

A worked example

An older streaming stick plays HD channels smoothly but shows a black screen on the 4K version of the same channel. The codec information reveals the 4K stream uses HEVC at a high bitrate, which the stick can only decode in software. Switching to the HD version fixes it for now; a newer device with HEVC and AV1 hardware decoding solves it for good.

The bottom line

Codecs compress video so it can stream. H.264 plays everywhere; HEVC and VP9 are more efficient and common for 4K; AV1 is the efficient newcomer that needs newer hardware. If 4K matters to you, choose devices with hardware support for HEVC and AV1 — and remember that bitrate matters as much as the codec itself.