Video Formats and Codecs
The difference between video format and codec remains one of the most common questions among users. The right choice directly affects quality, file size, loading speed, and device compatibility.
Important
The container (format) does not determine video quality. Quality is determined by the codec and bitrate.
What is a video codec
A video codec is a technology for compressing and decoding video streams. It works with images, frames, and sequences, reducing their size for convenient storage and transmission, then restoring them during playback.
The codec determines how video will be encoded inside the container and affects image quality, compression ratio, and computational resource requirements.
Popular codecs:
H.264 (AVC)
The most widespread. Features a good balance of quality and size. Supported everywhere
H.265 (HEVC)
Provides better quality at the same size but requires more computational resources. Limited support in older browsers and devices
VP9
Open alternative to HEVC. Actively used by YouTube. Works well in modern browsers
AV1
New open codec. The most efficient compression today. Ideal for streaming and web video, but not all devices have hardware support yet
MPEG-2
Outdated standard, used on DVDs
H.266 (VVC)
Successor to H.265. In practice, hardly used yet due to lack of widespread decoders
What is a video format (container)
Format (container) is the "wrapper" of a video file. It's a way of organizing and storing video data in a file. It defines the container structure, that is, how video streams, audio streams, subtitles, and service information are arranged inside the file.
The format is responsible for ensuring that different multimedia elements can be combined into one file and played correctly on devices and in programs.
Main containers
MP4
The most popular. Supports H.264, H.265, AV1. Excellent compatibility
MKV
Flexible container, supports any codecs, multiple audio tracks, subtitles. Ideal for archives and home media libraries
MOV
Apple container for macOS/iOS ecosystem
WEBM
Format for the web. Usually contains VP9 or AV1
AVI
Outdated format. Limited support for modern features
TS / M2TS
Transport streams for broadcasting, Blu-ray, and streaming
Which format to choose for different tasks
For websites
- MP4 (H.264) for maximum compatibility
- WEBM (VP9/AV1) to save traffic
- simultaneous delivery of two formats through <source>
For shooting and editing
- MOV (ProRes) — professional post-production work
- MP4 (H.264/H.265) — everyday shooting
For storing movies and series
- MKV (H.265 or AV1) — best quality at minimum size
For streaming
- HLS/DASH + H.264/AV1 — stability and adaptive bitrate.
What affects video size
File size is determined by
- codec (compression efficiency);
- bitrate;
- resolution;
- frames per second (FPS);
- noise level in the frame.
With equal parameters
- H.264 gives approximately 100% size
- H.265 — 60–70%
- VP9 — 50–65%
- AV1 — 40–50%
What about the future?
- 1AV1 will become the main codec for web and streaming. Hardware support grows every year.
- 2H.266 (VVC) will strengthen in the professional sphere, but licensing will slow mass adoption.
- 3Personalized and adaptive video will become the norm — platforms will deliver the optimal codec for a specific device.
- 4Growth in popularity of HDR, 10-bit video, 4K/8K, which strengthens the need for new compression algorithms.