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 ''com ...

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 The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and capable of s ...

and

HD DVD HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to ...

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 (TPM) such as access control technologies can restrict the use of proprietary hardware and copyrighted work ...

system used in high-definition optical disc formats.

Operation

When using an

AACS AACS may refer to: * Advanced Access Content System, a standard for content distribution and digital rights management ** AACS encryption key controversy * American Association of Christian Schools, an organization that unifies individual Christi ...

-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 High-bandwidth Digital Content Protection (HDCP) is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio and video content as it travels across connections. Types of connections include DisplayPort ...

(HDCP) system, available on some devices which support DVI and

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controll ...

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, 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 chan ...

) 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 image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the s ...

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

ed content. Without content protection, users with the appropriate equipment could easily

capture Capture may refer to: *Asteroid capture, a phenomenon in which an asteroid enters a stable orbit around another body *Capture, a software for lighting design, documentation and visualisation *"Capture" a song by Simon Townshend *Capture (band), an ...

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 (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the ...

early adopters 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

{{reflist

Operation

Rationale

References

See also