Video Formats

What is a Video Format?

A video format is made up of at least two different components, the container and the codec(s) used inside that container. The container describes the structure of the file where the various pieces are stored and a codec is a way of encoding audio or video into a stream of bytes. CoDec means Compression and Decompression of the data and there are many different algorithms standard created to do this.

To make things more confusing, some names such as "mpeg4", describe both a codec and a container, so it's not always clear from context which is being used.  You could have a movie encoded with an mpeg4 codec inside an avi container, or a movie encoded with the Sorenson codec inside an mpeg-4 container.

Common Container Formats

AVI (Audio Video Interleave): Most commonly contains M-JPEG (especially from digital cameras) or DivX (for whole movies), but can contain nearly any format.  Sometimes you'll see a reference to the "fourcc": this is a four-character code (such as "divx" or "mjpg") inside the AVI container which specifies which video codec is being used.

MOV (Quicktime): Most often used for the locked Apple Sorenson codec, or for Cinepak, but can also hold other codecs such as mjpeg, etc.

WMV (Windows Media Video): More or less MPEG4 which can contain nearly any codec, including several Microsoft spinoffs of MPEG-4 which vary in their freedom and licensing requirements.

FLV (Flash Video): A container file format used to deliver video over the Internet using Adobe Flash Player.

Common Codecs

H.264: is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video. Best known as being one of the codec standards for Blu-ray Discs, but it is also widely used by streaming internet sources such as Vimeo, YouTube, Brightcove and iTunes. It is also a commonly used standard in real-time videoconferencing.

MPEG (Moving Pictures Expert Group):
MPEG-1: Old, supported by everything (at least up to 352x240), reasonably efficient.  A good format for the web.
MPEG-2: An improved version of MPEG-1, with better compression.  720x480.  Used in HDTV, DVD, and SVCD.
MPEG-4: A family of codecs, some of which are open, others Microsoft proprietary.
M-JPEG: A version of JPEG image system that supports video.
Note: The MP3 format for audio files derived from the MPEG format.

DV (Digital Video): Usually used for video grabbed via firewire off a digital video camera.  Standard definition at 720x576 @ 25 FPS PAL (or 720x480 @ 29.97FPS NTSC).

HDV (High Defenition Video): Used by high definition digital video camera's. Anamorphic 1440x1080 @ 25 FPS PAL (Stretched to 1920x1080 on playback).

WMV (Windows Media Video): A collection of Microsoft proprietary video codecs.  Since version 7, it has used a special version of MPEG4.
WMV9: a proprietary, non-MPEG4 codec from Microsoft.

RM (Real Media): a closed codec developed by Real Networks for streaming video and audio. 
RP9: a very efficient streaming proprietary codec from Real media (not MPEG4).

DivX: in early versions an incomplete early MPEG-4 codec inside an AVI container, but DivX version 4 and later are a more full MPEG-4 codec.  It does require more horsepower to play than mpeg1, but less than mpeg2. 

Sorenson 3: Apple's proprietary codec, commonly used for distributing movie trailers (inside a quicktime container).
Quicktime 6: Apple's implementation of an MPEG4 codec.