 | |
| Filename extension | ivf |
|---|---|
| Internet media type | video/x-ivf, video/x-indeo |
| Developed by | Intel Architecture Labs |
| Initial release | November 1992; 32 years ago (1992-11) |
| Latest release | 5.11 |
| Type of format | compressed video |
| Contained by | AVI |
| Extended from | DVI |
Indeo Video (commonly known now simply as "Indeo") is a family of audio andvideo formats andcodecs first released in 1992, and designed for real-time video playback on desktop CPUs. While its original version was related to Intel'sDVI video stream format, a hardware-only codec for the compression of television-quality video ontocompact discs, Indeo was distinguished by being one of the first codecs allowing full-speed video playback without usinghardware acceleration. Also unlikeCinepak andTrueMotion S, the compression used the sameY'CbCr4:2:0colorspace as the ITU'sH.261 andISO'sMPEG-1.Indeo use was free of charge[1] to allow for broadest usage.
During the development of what became theP5Pentium microprocessor, theIntel 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-onlyDigital Video Interactive (DVI) which was previously developed byGeneral Electric.[2] Indeo was first released in 1992 along withMicrosoft'sVideo for Windows platform.[3] At its public introduction, it was the only video codec supported in both the Microsoft (Video for Windows) andApple Computer'sQuickTime software environments, as well as by IBM's software systems of the day. It was sold toLigos 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 remainedproprietary. Intel slowed development and stopped active marketing, and it was quickly surpassed in popularity by the rise ofMPEG codecs and others, as processors became more powerful and its optimization for Intel's chips less important. Indeo still saw some use invideo gamecutscene videos, such as in 1998'sPolice Quest: SWAT 2.
The original format was designed for real-time playback on low-end Intel CPUs (i386 andi486), optionally supported by specialized decoder hardware (Intel i750). Decoding complexity was significantly lower than with contemporary MPEG codecs (H.261,MPEG-1 Part 2).[4]
The codec was highlyasymmetrical, meaning that it took much more computation toencode a video stream than to decode it. Intel's ProShare video conferencing system took advantage of this, using hardware acceleration to encode the stream (and thus requiring an add-in card), but allowing the stream to be displayed on any personal computer.
Indeo 2, previously known asReal-Time Video 2, works bydelta coding pixels line by line, either against the temporally or spatially directly preceding line, coupled with staticHuffman coding.[5]
Indeo Video 3 is a traditionalDCT-based transform coding format designed for video playback fromCD-ROM that is very similar to the competingCinepak. It useschroma subsampling, delta encoding,vector quantization,run-length encoding andmotion compensation (inter-frame coding) with a recommended key-frame interval of 4 and has distinctly asymmetric runtime characteristics.[6][3]
Indeo Video Interactive had greater computational complexity and was aimed at video game developers.[7] It was based onwavelet transforms[8] and included novel features such aschroma-keyed transparency and hot spot support. Initially, there was no support for Apple systems.[9] 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.[10]
Indeo Audio Coder is a transform coding format based on themodified discrete cosine transform (MDCT).[11]
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."[12]Windows implementations of Indeo have been distributed by Ligos.Apple distributed Mac versions for "classic" operating systems through OS 9, but there is noMacOS support forMac OS X.
Official Indeo 5 decoders exist forMicrosoft Windows, theclassic Mac OS,BeOS R5 and theXAnim player onUnix. Reverse engineered decoders for versions 2, 3, 4 and 5 were introduced inFFmpeg between 2003 and 2011.[13] Indeo version 3 (IV31 andIV32), 4 (IV41) and 5 (IV50) are supported byMPlayer[14] and XAnim. Version 5.11 isfreeware[15] 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[16] 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[17]
The Microsoft Windows implementation of the Indeo codec contains several security vulnerabilities and one should not play Indeo videos from untrusted sources. Microsoft tried to remove them in XP SP1 but had to release a hotfix to add it back.[18] The codec was originally licensed from Intel and Microsoft likely do not 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.[19]