What is H.264 / AVC?
H.264, AVC and MPEG-4 Part 10 describe the same video coding standard. It is a codec standard, not a container, and files using H.264 are commonly stored in MP4, MOV, MKV and transport-stream containers.
avc1 is a codec identifier commonly used for H.264 in MP4-family files. x264 is an encoder implementation that produces H.264; it is not a different video format.Profiles, bit depth and chroma
| Profile family | Bit depth | Chroma capability | Typical use |
|---|---|---|---|
| Baseline / Main / High | 8-bit | Primarily 4:2:0 | Consumer and web video |
| High 10 | 8–10-bit | 4:2:0 | Higher-precision/specialist workflows |
| High 4:2:2 | 8–10-bit | Up to 4:2:2 | Professional production |
| High 4:4:4 Predictive | Up to 14-bit | Up to 4:4:4 | Specialist/professional coding |
Most H.264 encountered in phones, cameras, downloads and web video is 8-bit 4:2:0. The existence of higher profiles does not mean every decoder supports them.
Profiles and levels answer different questions
A profile says which coding tools and colour formats may be used. A level constrains decoder workload such as picture size, macroblock rate and bitrate. That is why “H.264 supports 4K” is incomplete without knowing the profile/level and the decoder.
Names you may see
- H.264 / AVC / MPEG-4 AVC / MPEG-4 Part 10: the coding standard.
- avc1: a common MP4 codec/sample-entry identifier for H.264.
- x264: a widely used software encoder for H.264.
- .mp4 / .mkv / .mov: containers that may carry H.264, but do not guarantee it.
Where H.264 still fits
H.264 remains a strong compatibility choice because hardware decoding is widespread. HEVC and AV1 can be more compression-efficient, but support, licensing, encode time and device age can make H.264 the safer delivery format.
See H.264 vs H.265 and H.264 vs AV1.