The Image Constraint Token (ICT) is a protocol flag that can cause

downsampling In digital signal processing, downsampling, compression, and decimation are terms associated with the process of ''resampling'' in a multi-rate digital signal processing system. Both ''downsampling'' and ''decimation'' can be synonymous with ''co ...

high-definition video High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image with considerably more than 480 vertical scan lines ( ...

content on

Blu-ray Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-defin ...

and

HD DVD HD DVD (short for High Density Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video.

to slightly-better-than-DVD quality video. It is part of the

Advanced Access Content System The Advanced Access Content System (AACS) is a standard for content distribution and digital rights management, intended to restrict access to and copying of the post-DVD generation of optical discs. The specification was publicly released in ...

, the

digital rights management Digital rights management (DRM) is the management of legal access to digital content. Various tools or technological protection measures, such as access control technologies, can restrict the use of proprietary hardware and copyrighted works. DRM ...

system used in high-definition optical disc formats.

Operation

When using an AACS-enabled player, all components in the display chain (including the display panel) must be considered "secure". This security is enforced through the High-bandwidth Digital Content Protection (HDCP) system, available on some devices which support DVI and

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...

video connections. If any components in the display chain do not support HDCP (such as a display connected to the player through analog connections like

component Component may refer to: In engineering, science, and technology Generic systems *System components, an entity with discrete structure, such as an assembly or software module, within a system considered at a particular level of analysis * Lumped e ...

, composite or

S-Video S-Video (also known as separate video, Y/C, and erroneously Super-Video) is an analog video signal format that carries standard-definition video, typically at 525 lines or 625 lines. It encodes video luma and chrominance on two separate chann ...

) and the ICT flag is enabled, the player automatically reduces the high-definition video to the resolution of 960x540

pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...

s before outputting it. Hence, while higher resolution than that of a standard

DVD The DVD (common abbreviation for digital video disc or digital versatile disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any ki ...

, the resulting video signal is no longer truly high-definition. The Image Constraint Token applies on a ''per disc'' basis, so that one movie title could have it enabled while another from a different studio could have it disabled. It impacts video only, and has no effect on audio signal quality. Discs with ICT enabled will (theoretically) have it marked on the outside of package, allowing consumers to see if the specific disc has the flag enabled. Note that ICT in conjunction with HDCP is used to protect the ''display path'' over which the video data travels, not the actual data on the disc itself.

Rationale

The use of ICT is an attempt to prevent individuals from creating unauthorized high-resolution copies of

copyright A copyright is a type of intellectual property that gives its owner the exclusive legal right to copy, distribute, adapt, display, and perform a creative work, usually for a limited time. The creative work may be in a literary, artistic, ...

ed content. Without content protection, users with the appropriate equipment could easily capture each and every frame of the film at its full resolution, effectively making a "perfect" copy. Although this danger is greatest for unsecured digital outputs, analog outputs also allow copies to be made, albeit with a potential for slightly reduced quality. Some

HDTV High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it ref ...

early adopter An early adopter or lighthouse customer is an early customer of a given company, product, or technology. The term originates from Everett M. Rogers' ''Diffusion of Innovations'' (1962). History Typically, early adopters are customers who, in a ...

s object to the ICT flag because initial HDTVs did not incorporate HDCP support and thus, if this was activated, these individuals would not be able to enjoy high-definition video from such discs.

References

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Operation

Rationale

References

See also