Codec Basics for IPTV: H.264, H.265 and AV1

H.264, H.265 and AV1 are video codecs — the methods used to compress video so it can be streamed and stored efficiently, then decompressed again for playback. They differ mainly in how efficiently they compress, how widely devices can decode them, and how complex or costly they are to use. A newer codec can often deliver similar quality at a lower bitrate, but only if the player and device can actually decode it.

What Is a Video Codec?

Codec is short for coder-decoder. Raw video is far too large to stream in its original form, so a codec compresses it on the way out (encoding) and reconstructs it for viewing (decoding). Most video compression is "lossy", meaning it discards detail the eye is less likely to notice in order to shrink the data — how much it discards depends on the bitrate and settings chosen.

Decoding can happen in dedicated hardware or in software. Hardware decoding is efficient and easy on the battery, which is why smart TVs, phones and streaming boxes ship with decoders for common codecs. Software decoding is possible when hardware support is missing, but it is more demanding and can struggle on low-powered devices — which is one reason codec support, not just codec efficiency, matters so much in practice.

H.264 — AVC

H.264, also called AVC (Advanced Video Coding), is the most established of the three. It has very broad hardware and software support across modern and many older playback devices, and it is well understood by encoders and players alike. It is licensed through patent pools, but its wide support has made it the safe default for compatibility.

The trade-off is efficiency: for a given level of quality, H.264 generally needs a higher bitrate than the newer codecs. For many services that is an acceptable price for the confidence that a very wide range of devices can play the stream.

H.265 — HEVC

H.265, also called HEVC (High Efficiency Video Coding), was designed as a more efficient successor to H.264. In many cases it can deliver similar visual quality at a noticeably lower bitrate, though the exact saving varies with the content, the encoder and the settings — it is not a fixed number.

Two things complicated its rollout. Its licensing is more fragmented, with multiple patent pools, which made some providers cautious. And while hardware decoding is common on newer devices, it is not as broad as H.264, so older hardware may not support it. HEVC is widely used, especially for higher-resolution content, but its support cannot simply be assumed everywhere.

AV1

AV1, developed by the Alliance for Open Media, is a newer codec designed to be highly efficient and royalty-free. In many tests it can match or exceed HEVC's compression, again depending on the content, encoder and settings. Its royalty-free status is a large part of its appeal for major streaming platforms.

AV1 has trade-offs of its own. Encoding is computationally heavy, which can make it slower or more expensive to produce, and hardware decode support — while growing steadily on newer devices — is not yet as broad as H.264 or H.265. Software decoding is possible but demanding, so older or low-powered devices may not handle it smoothly. It is best thought of as efficient and increasingly capable, but still maturing in the field.

Why Codec Compatibility Matters

Because the service and its encoder choose the codec, the key question on your side is whether your device and player can decode whatever arrives. When they can, a more efficient codec can mean smoother playback at a given connection speed. When they cannot, the result is usually no playback, a fallback to a lower-quality stream where one exists, or heavy software decoding that strains the device.

This can produce confusing symptoms. A situation where Live TV plays normally but one VOD title will not play is sometimes caused by codec compatibility: the working stream may use H.264, while the failing title uses H.265 or AV1 that the device or player cannot decode correctly. That is only one possible cause, though — network conditions and account or content configuration can produce similar symptoms, so it should not be treated as a universal diagnosis.

It also helps to separate resolution from bitrate. Two 1080p streams can use very different bitrates, even when they use the same codec; likewise, a 1080p H.265 stream may require a different bitrate from a 1080p H.264 stream at a similar quality target. And no codec can compensate for an unstable connection — if the network cannot sustain the bitrate, buffering or quality drops follow regardless of efficiency, as covered in our guide on IPTV network requirements.

Which Codec Is Best for IPTV?

There is no single best codec — it depends on the stage and the environment. In practice, H.264 remains the safe choice for maximum compatibility, H.265 is common where efficiency matters and devices support it, and AV1 is used increasingly by large platforms that can benefit from its efficiency and royalty-free licensing.

It is also worth knowing that the viewer normally cannot simply switch from one codec to another. That is only possible when the service provides an alternative rendition or stream version that the player can select, and not every service offers one.

So if a particular stream will not play while others do, a codec the device cannot decode is one cause worth checking — alongside network stability and account or content factors. For on-demand titles specifically, our guide on what VOD is in IPTV explains how those libraries are delivered.