Dirac – New successor HD open source video codec

By Detector | 19 September 2008




Dirac Pro is a open source video compression system developed by BBC that provides general-purpose video compression and decompression tools comparable with state-of-the-art systems. This codec covers all applications from internet streaming to Ultra-high definition TV in a flexible and scalable way.

The Dirac Pro specification describes a sub-set of the main Dirac Specification, and is aimed at high bitrate I-Frame only applications for studio and professional use. Dirac Pro consists of the intra coding tools contained within Dirac and is aimed at professional applications that provides efficient coding at many resolutions including various flavors of CIF, SDTV and HDTV. Dirac Pro has been proposed for standardization within the Society of Motion Picture and Television Engineers (SMPTE) as VC-2.

With other words, it can compress any size of picture from low-resolution QCIF (176×144 pixels) to HDTV (1920×1080) and beyond. It promises significant savings in bandwidth and improvements in quality over existing codecs, by some claims even superior to those promised by the latest generation of codecs such as H.264/MPEG-4 AVC or SMPTE’s VC-1 (which is based on Microsoft’s WMV 9). Dirac’s implementors make the preliminary claim of “a two-fold reduction in bit rate over MPEG-2 for high definition video”[1], an estimate which would put the design in about the same class of compression capability as the latest standardization efforts of H.264/MPEG-4 AVC and VC-1. MPEG-2 is the previous generation video codec used in the standard DVD format today.

Dirac employs wavelet compression, instead of the discrete cosine transforms used in most older codecs (such as H.264/MPEG-4 AVC or SMPTE’s VC-1). Dirac is one of several projects attempting to apply wavelets to video compression. Others include Rududu [2], Snow and Tarkin. Wavelet compression has already proven its viability in the JPEG 2000 compression standard for photographic images.

Wavelet decompres the video signal into frequency bands. It is designed to be simple, flexible, and highly effective. It can operate across a wide range of resolutions and application domains, including the delivery of standard-definition and high-definition television, cinema production and distribution, and can be implemented also with low-power devices for use in embedded applications like mobile phones, portable video player..

The best of all Dirac is open source codec. The main project can be found on SourceForge at http://dirac.sourceforge.net and it is developed under the Mozilla general public license v1.1. by the BBC for free use – for anybody and for any purpose.

More info here.

Info about compiling and testing the codec here.

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2 Responses to “Dirac – New successor HD open source video codec”

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