Video codec
Also known as: video compression format, video coding format
A video codec (short for coder-decoder) is technology that compresses video into much smaller files for storage and streaming, then decompresses it for playback.
Without codecs, an hour of HD video would take hundreds of gigabytes. Common codecs include H.264 (AVC), H.265 (HEVC), VP9, and AV1, each offering better compression than the last. While newer codecs save bandwidth and storage, devices need hardware support to play them smoothly and efficiently.
Video codec, explained at three levels
At home
A codec is like vacuum-packing clothes for a suitcase. It squeezes video down to travel over the internet, then unpacks it when you watch.
At work
Video codecs affect the quality and bandwidth of video calls, training videos, and security camera footage.
At home
If a video won't play or shows only sound, your device may not support its codec. Apps like VLC include many codecs and play almost anything.
At work
Codec choice balances quality, file size, encoding speed, compatibility, and licensing. Security cameras using H.265 save storage but need compatible viewing software.
At home
Newer codecs save data on phone plans when streaming, but only if your device supports them in hardware. In my opinion, it's a hidden reason newer phones last longer on battery while streaming.
At work
Plan storage and bandwidth around codec efficiency, check hardware decode support across your device fleet, consider licensing costs for patent-encumbered codecs, and test video platforms on older devices.
Real-world examples
At home
Lena couldn't play a video file her friend sent. Installing VLC media player, which supports more codecs, solved it instantly.
At work
Marcus manages security cameras for a Sudbury retail chain. Switching to H.265 cameras cut video storage needs nearly in half.
How it compares
| feature | H.264 | HEVC (H.265) | AV1 |
|---|---|---|---|
| Released | 2003 | 2013 | 2018 |
| Compression | Good | Better | Best |
| Licensing | Royalties, widely licensed | Complex royalties | Royalty-free |
| Device support | Universal | Wide | Growing |
Newer codecs compress better but need newer hardware.
For analysts
For video-heavy systems like cameras or training platforms, I'd model storage and bandwidth with the actual codec. It can halve infrastructure costs.
History & origin
Digital video compression standards emerged in the late 1980s, with H.261 in 1988 for video calls and MPEG-2 in the mid-1990s powering DVDs and digital TV. H.264, standardized in 2003, became the backbone of Blu-ray discs, YouTube, and streaming for over a decade. HEVC, or H.265, followed in 2013, halving file sizes but facing complicated patent licensing. Google released VP9 royalty-free in 2013, and the Alliance for Open Media, formed in 2015 by companies including Google, Netflix, Amazon, and Microsoft, released the royalty-free AV1 codec in 2018. Newer chips in phones, TVs, and computers increasingly decode AV1 in hardware. In my view, codecs are why streaming 4K movies over a home connection is even possible.