as Real-Time Video 2, works by delta coding pixels line by line, either against the temporally or spatially directly preceding line, coupled with static Huffman coding. Indeo Video 3 Indeo Video 3 is a traditional DCT-based transform coding format designed for video playback from CD-ROM that is very similar to the competing Cinepak. It uses chroma subsampling, delta encoding, vector quantization, run-length encoding and motion compensation (inter-frame coding) with a recommended key-frame interval of 4 and has distinctly asymmetric runtime characteristics. Indeo Video Interactive Indeo Video Interactive had greater computational complexity and was aimed at video game developers. It was based on wavelet transforms and included novel features such as chroma-keyed transparency and hot spot support. Initially, there was no support for Apple systems. Two variants of this technology were produced: Indeo Video 4 and 5. The format was never officially documented but later reverse engineered to allow for third-party decoders. Indeo Audio Coder Indeo Audio Coder is a transform coding format based on the modified discrete cosine transform (MDCT). Indeo Version 5 Proprietary bitstream encoding for video, originally developed by Intel. The technology was sold in 2000 to Ligos Corporation. John McGowan states that Indeo 5 employs a wavelet algorithm and other encoding features; its predecessor Indeo 4 employs a presumably similar "hybrid wavelet algorithm." Windows implementations of Indeo have been distributed by Ligos. Apple distributed Mac versions for "classic" operating systems through OS 9, but there is no MacOS support for Mac OS X. Implementations Official Indeo 5 decoders exist for Microsoft Windows, the classic Mac OS, BeOS R5 and the XAnim player on Unix. Reverse engineered decoders for versions 2, 3, 4 and 5 were introduced in FFmpeg between 2003 and 2011. Indeo version 3 (IV31 and IV32), 4 (IV41) and 5 (IV50) are supported by MPlayer and XAnim. Version 5.11 is freeware and may be used on all 32-bit versions of Windows prior to Vista. Version 5.2 has been created for XP and is available for purchase from the official website for use only with Windows 95, 98, ME, NT, 2000 and XP. This includes support for Indeo Video 4.5 and Indeo Audio 2.5 codecs but the version 3.2 video codec has been removed since the original release of Indeo XP for Windows. Although Indeo video is not officially supported by Windows Vista and Windows 7, simply entering the following into the command prompt might enable