Digital Formats · Video

Digital Video
Formats

Codecs, containers, and compression — how motion pictures are encoded, stored, and played back.

01 How video codecs work

A codec (coder-decoder) is software that compresses video for storage and decompresses it for playback. Without codecs, only the most powerful computers could handle raw video.

Raw video
Large uncompressed data
→
Encoder
Compresses & writes file
→
File on disk
.mp4, .mov, .avi…
→
Decoder
Decompresses for playback
→
Playback
Screen output
MPEG-4 Advanced compression algorithm. Can compress a 120-minute film to ~300 MB. The basis for .mp4 and many streaming formats.
DivX Movie-encoding codec built on MPEG-4. Used to fit full movies onto a single DVD. DivX HD extends this to high-definition content.
02 Resolution & frame rate

Resolution is the pixel count (width × height) of each video frame. Higher resolution = more detail = larger file.

SD 480p
640 × 480
4:3
HD 720p
1280 × 720
16:9
FHD 1080p
1920 × 1080
16:9
QHD 1440p
2560 × 1440
16:9
4K UHD
3840 × 2160
16:9

Common frame rates

24
fps · cinema
30
fps · standard
60
fps · smooth
120
fps · gaming
03 Format profiles
.mp4
Lossy / MPEG-4
The most common internet video format. Small file size, universal device support. Can store video, audio, subtitles, and still images in one container.
universal streaming small files
.mov
Lossy / QuickTime
Apple's QuickTime format. Supports video, audio, text tracks, and timecodes. Easier to edit than MP4. Plays on Windows via VLC but not natively.
Apple editable VLC on Windows
.avi
Uncompressed
Audio Video Interleave — created by Microsoft in 1992 for Video for Windows. Uncompressed, very large files. Made of RIFF chunks storing metadata and A/V data separately.
1992 legacy Windows only large files
.wmv
Lossy / Microsoft
Windows Media Video — Microsoft's proprietary compressed format based on ASF (Advanced Systems Format). Requires additional software to play on macOS.
Windows proprietary limited support
04 Side-by-side comparison
Format Compression Cross-platform Editable File size Best for
.mp4 Lossy Yes Moderate Small Web, streaming, sharing
.mov Lossy Mac + VLC Easy Medium Editing, Apple ecosystem
.avi None Windows Yes Very large Legacy archiving
.wmv Lossy Windows Limited Small–Med Windows Media Player
.mp4 — universal
.mov — Apple
.avi — legacy
.wmv — Windows
Digital Literacy · 2025