Advanced Access Content System: Difference between revisions

Revision as of 20:55, 9 September 2016

Revision as of 12:47, 14 June 2017

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To read the Volume ID, a cryptographic [[Public key certificate|certificate]] (the ''Private Host Key'') signed by the AACS LA is required. However, this has been circumvented by modifying the firmware of some HD DVD and Blu-ray drives.<ref name=arstechnica-aacs>{{cite web

|url = httphttps://arstechnica.com/news.ars/post/20070415-aacs-cracks-cannot-be-revoked-says-hacker.html

|title = New AACS cracks cannot be revoked, says hacker.

|accessdate = 2007-05-04

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{{main|Image Constraint Token}}

AACS-compliant players must follow guidelines pertaining to outputs over analog connections. This is set by a flag called the Image Constraint Token (ICT), which restricts the resolution for analog outputs to 960×540. Full 1920×1080 resolution is restricted to HDMI or DVI outputs that support [[High-bandwidth Digital Content Protection|HDCP]]. The decision to set the flag to restrict output ("down-convert") is left to the content provider. Warner Pictures is a proponent of ICT, and it is expected that Paramount and Universal will implement down-conversion as well.<ref>{{cite web|url=http://www.videobusiness.com/article/CA6300812.html |title=High-def ‘down-converting’ forced |accessdate=2007-05-04 |date=19 January 2006 |last=Sweeting |first=Paul |work=Video Business |deadurl=yes |archiveurl=https://web.archive.org/web/20060415091053/http://www.videobusiness.com/article/CA6300812.html |archivedate=15 April 2006 }}</ref>

AACS guidelines require that any title which implements the ICT must clearly state so on the packaging. The German magazine "Der Spiegel" has reported about an unofficial agreement between film studios and electronics manufacturers to not use ICT until 2010 – 2012.<ref>{{cite web |url=httphttps://arstechnica.com/news.ars/post/20060521-6880.html |title=Hollywood reportedly in agreement to delay forced quality downgrades for Blu-ray, HD DVD |accessdate=2007-11-02 |author =Ken Fisher |date=21 May 2006 |work=arstechnica.com| archiveurl= https://web.archive.org/web/20071105063630/http://arstechnica.com/news.ars/post/20060521-6880.html| archivedate= 5 November 2007 <!--DASHBot-->| deadurl= no}}</ref> However, some titles have already been released that apply ICT.<ref>{{cite web |url=http://www.areadvd.de/news/2007/200710/29102007001_RE_HD_DVD.shtml |title=HD DVD: "Resident Evil" nur in Standard-Auflösung via YUV |accessdate=2007-11-02 |date=29 October 2007 |work=areadvd.de |language=German}}</ref>

=== Audio watermarking ===

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| work = PC World}}

</ref> It was expected to be a part of the final AACS specification.<ref>{{Cite web

|url= httphttps://arstechnica.com/gadgets/news/2007/05/hd-dvd-blu-ray-managed-copy-coming-later-this-year.ars

|title=HD DVD, Blu-ray "Managed Copy" coming later this year

|work=arstechnica.com

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There is also commercial software ([[AnyDVD|AnyDVD HD]]) that can circumvent the AACS protection. Apparently this program works even with movies released after the AACS LA expired the first batch of keys.<ref>

{{cite web

|url=httphttps://arstechnica.com/news.ars/post/20070517-latest-aacs-revision-defeated-a-week-before-release.html

|title=Latest AACS revision defeated a week before release

|accessdate=2007-05-29

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</ref> The patents were filed in 1999 and 2001 respectively, and in 2003 the [[National Security Agency]] paid $25 million for the right to use 26 of Certicom's patents, including the two that Sony is alleged to have infringed on.<ref>

{{cite web

|url=httphttps://arstechnica.com/news.ars/post/20070531-encryption-vendor-claims-aacs-infringes-its-patents-sues-sony.html

|title=Encryption vendor claims AACS infringes its patents, sues Sony

|accessdate=2007-05-31