This article is part of our guide IPTV and Streaming Glossary: Key Terms Explained Simply.
A codec (short for coder-decoder) is the method used to compress video for streaming and decompress it for playback. The codec a stream uses affects how much bandwidth it needs — and whether your device can play it smoothly. This guide explains the common video and audio codecs in plain language.
Why codecs matter
Uncompressed video would be far too large to stream. Codecs remove information viewers are unlikely to notice. Newer codecs are more efficient — they can deliver similar picture quality at a lower bitrate — but they need more capable hardware to decode.
If your device cannot decode a codec efficiently, you may see stuttering, high processor load or a black screen with sound. See black screen with sound.
The main video codecs
| Codec | Also called | Efficiency | Device support |
|---|---|---|---|
| H.264 | AVC | Baseline | Almost universal |
| H.265 | HEVC | More efficient than H.264 | Most modern TVs, sticks and phones |
| VP9 | — | Similar to HEVC | Many Android-based devices and browsers |
| AV1 | — | More efficient again | Newer devices; support is growing |
H.264 (AVC)
The most widely supported video codec. Almost every streaming device, TV, phone and computer can decode it in hardware. Many live streams still use it.
H.265 (HEVC)
Commonly described as offering similar quality to H.264 at a substantially lower bitrate, which makes it popular for 4K and HDR. Most modern devices support it in hardware, but some older or low-cost devices do not.
VP9
Developed by Google, widely used on the web. Supported by many Android-based devices and modern browsers.
AV1
A royalty-free codec developed by the Alliance for Open Media. It is highly efficient, but hardware decoding support is mainly found in newer devices.
Audio codecs
| Codec | Typical use |
|---|---|
| AAC | Very common for stereo streaming audio |
| AC-3 (Dolby Digital) | Surround sound, common in broadcasts |
| E-AC-3 (Dolby Digital Plus) | Surround sound for streaming |
| MP2 / MP3 | Older broadcast and general audio |
If you hear no sound on some channels, the device or player may not support that audio codec, or it may need passthrough to a soundbar or receiver that can decode it. Switching audio tracks can help; see subtitles and audio tracks.
Hardware vs. software decoding
- Hardware decoding uses a dedicated chip. It is efficient and smooth, but only for codecs the chip supports.
- Software decoding uses the main processor. It supports more codecs but may stutter on low-powered devices.
Many players let you switch between the two. If a channel misbehaves, switching is a quick test.
How to check what your device supports
- Look at the technical specifications on the manufacturer's website, under video formats or codecs.
- Check whether the device is advertised for 4K HDR — most such devices support HEVC.
- Use your player's stream information panel, if it has one, to see the codec of the current channel.
If you are choosing a new device, see how to choose an Android TV box and the device compatibility checklist.
Frequently asked questions
Does HEVC look better than H.264?
At the same bitrate, HEVC can look better because it compresses more efficiently. At a high enough bitrate, both can look excellent.
Why does one channel stutter while others are fine?
That channel may use a codec your device decodes in software rather than hardware. Try switching the decoder setting or use another device.
Do I need to install codecs?
On TVs and streaming sticks, no — codec support is built into the device and the player. On computers, players such as VLC include their own codecs.
Choosing and checking codecs
H.264 plays almost everywhere, HEVC and VP9 are more efficient and common for 4K, and AV1 is the newest option for recent devices. Hardware decoding support decides how smoothly your device plays each. For how codecs fit into the bigger picture, read how IPTV works, and for other technical terms, see the streaming glossary.