Indeo Video is a family of audio and video formats and codecs first released in 1992, and designed for real-time video playback on desktop CPUs. While its original version was related to Intel's DVIvideo stream format, a hardware-only codec for the compression of television-quality video onto compact discs, Indeo was distinguished by being one of the first codecs allowing full-speed video playback without using hardware acceleration. Also unlike Cinepak and TrueMotion S, the compression used the same Y'CbCr 4:2:0 colorspace as the ITU's H.261 and ISO's MPEG-1. Indeo use was free of charge to allow for broadest usage.
History
During the development of what became the P5Pentium microprocessor, the Intel Architecture Labs implemented one of the first, and at the time highest-quality, software-only video codecs, which was marketed as "Indeo Video". It has been developed since the 1980s based on the hardware-only Digital Video Interactive which was previously developed by General Electric. Indeo was first released in 1992 along with Microsoft's Video for Windows platform. At its public introduction, it was the only video codec supported in both the Microsoft and Apple Computer's QuickTime software environments, as well as by IBM's software systems of the day. It was sold to Ligos Corporation in 2000. Intel produced several different versions of the codec between 1993 and 2000, based on very different underlying mathematics and having different features. Though Indeo saw significant usage in the mid-1990s, it remained proprietary. Intel slowed development and stopped active marketing, and it was quickly surpassed in popularity by the rise of MPEG codecs and others, as processors became more powerful and its optimization for Intel's chips less important. Indeo still saw some use in video gamecutscene videos, such as in 1998's .
Formats
The original format was designed for real-time playback on low-end Intel CPUs, optionally supported by specialized decoder hardware. Decoding complexity was significantly lower than with contemporary MPEG codecs. The codec was highly asymmetrical, meaning that it took much more computation to encode a video stream than to decode it. Intel's ProSharevideo conferencing system took advantage of this, using hardware acceleration to encode the stream, but allowing the stream to be displayed on any personal computer.
Indeo 2
previously known 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.
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.
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, 4 and 5 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 the playback of Indeo encoded video: regsvr32 ir50_32.dll
Security advisory
The Microsoft Windows implementation of the Indeo codec contains several security vulnerabilities and one should not play Indeo videos from untrusted sources. MS tried to remove them in XP SP1 but had to release a hotfix to add it back . The codec was originally licensed from Intel and MS likely don't have the source code that would be required to fix the vulnerabilities. On fully patched systems and all Windows Vista and later systems the Indeo codec is partially disabled in most circumstances.
