4k Theoretical Discussion What content is 4k? “Mastered in 4k” Blu-ray Digital Cinema Cameras Differentiating 4k from HD
Defining 4k
Finish in 4k Digital 4k Files 4k Cinema Sony F65 – shoot in 4k Downscal Finish in Master in “Mastered Blu-ray e to 2k 2k HD in 4k” Scan in 4k 2k Digital Shoot on film Film Scanner Cinema Scan in 2k Master in Blu-ray HD Film in Archive Finish in 2k Digital 2k Files 2k Cinema Sony F35 – shoot in HD
Digital Cinema Cameras
HD and 2k Cameras
4k Cameras Pixel count: G=4096, B=2048, R=2048 Pixel count: G=2560, B=1280, R=1280
4k or not? Unconfirmed pixel count: G=2048, B=1024, R=1024 Pixel count: G=2240, B=1120, R=1120 Sony F55 23.6mm x 13.3mm
Making 4k better than HD
Differentiating 4k from HD Higher resolution alone is not enough, 4k has to be TV Best Sofa 8’ from differentiated from HD in four viewing screen distance ways: 24” Standard Def 8’ Ideal • Higher resolution 65” High Def 8’ Ideal • Greater bit depth 85” 4k 5’ Could sit closer • 10-12 bits vs. 8 bits 130” 4k 8’ Ideal • Higher dynamic range • Better shadows and highlights • Wider color gamut • Display more colors
xvYCC color for 4k and HD
xvYCC Color • Background: – xvYCC is a color space that supports a gamut larger than the color space of HDTV which is called Rec 709 – xvYCC was proposed by Sony and published in January 2006 as an IEC standard – xvYCC makes use of code values that are not defined in Rec 709 – The Bravia XBR8 supported xvYCC but the feature was removed in later models • Blu-ray discs mastered in xvYCC will be watched by many consumers on TVs that do not support xvYCC – Blu-ray players will not convert from xvYCC to Rec 709 – The way that a Rec 709 TV displays xvYCC code values undefined in Rec 709 is also not defined – No way of knowing what other manufacturer’s sets will do • Care has to be taken when mastering xvYCC content to ensure it looks good when displayed on a Rec 709 TV
Mastering xvYCC QC on xvYCC BD Master Transform display xvYCC P3 & Color Master Correction QC on Rec 709 display Notes: Rec • P3 is the color space for digital QC on Rec iTunes cinema and all theatrical content Transform 709 709 display Master is mastered in P3 Master • Rec 709 is the standard color space for HDTV • The xvYCC color space is larger than Rec 709 but smaller than P3
Tactical Discussion: Creating more 4k content New movies and TV Restorations
Creating New 4k Content Shoot in 4k Finish in 4k • Obstacles: • Obstacles: – Arri Alexa 2k camera is very popular with film – Most post houses cannot display 4k makers and TV producers – Not all finishing systems can handle 4k – Significantly more data to unload from card, – HD TV workflows are established and time critical – finishing in store and transfer 4k will be incremental – • High cost of memory cards for Sony F65 4k Effects in 4k camera – Rendering in 4k will take 4x as long as rendering in 2k – F65 is not a finished product – Some effects can take 100 hours per frame to render just in 2k – Can render in 2k, and up scale to 4k – Red Epic does not look as good as Alexa or F65 – Can render in more than 2k but less than 4k and up scale to 4k
4k Restorations • Can restore anything shot on 35mm or 65/70mm film in 4k – Decreasing number of titles shot on film in last 10 years • All SPE restorations* were scanned in 4k but many were finished in 2k – Dirt and scratch fixes done in 2k have to be repeated in 4k • Some studios have restored a number of titles in 4k – Many 4k restorations done at Colorworks or Warner Bros’ MPI facility – Not a large number of titles • Further review needed in order to determine which library titles are suitable for 4k restoration *Not all re-mastering is a restoration
Content protection for 4k Studios’ Viewpoint HDMI Link DRM
Starting Point • 4k in the home is being driven by CE. • Studios show little interest in releasing 4k to the home. • Studios can and will likely wait for an enhanced content protection system before releasing 4k premium content. • Enhanced content protection debate has already started in Ultraviolet – Studios want enhanced content protection for HD – Implementers have proposed it for 4k, early window and 3D • Blu-ray was different. Both CE and studios wanted HD discs therefore compromises were made. 4/7/15 17 Sony Pictures Confidential
Content Protection Overview DRM Link Protection – Last six feet • HDCP over HDMI interface – HDCP 1.x is compromised • Protecting the content from the service provider all the way to the video buffers – HDCP 2.1 is much more secure • Ultraviolet has 5 DRMs for improved interoperability – Sony 4k products only have HDCP 1.x • Today’s DRMs rely on renewable components to • DTCP-IP respond to security breaches – Link protection for DNLA – E.g. Adobe Flash player updates – Not all Sony products with DNLA have DTCP-IP • Most DRMs today are “hack one, hack all” (that means there is no premium content over – When the DRM is compromised, all titles published to date DNLA) are exposed – Some studios do not believe DTCP robustness requirements are good enough.
HDCP Link Protection HDCP 1.4 HDCP 2.1 • • HDCP 1.0 published in 2003 HDCP 2.0 published in 2008, HDCP 2.1 published in 2011 • 56-bit proprietary encryption algorithm • HDCP 2.1 has higher robustness requirements that HDCP 1.4 • Key generation algorithm secrets were reverse engineered so device keys can be • 128-bit AES standard encryption generated by anyone • New security model, not vulnerable to same attack • HDCP has no response for that scenario as HDCP 1.4 Studios will require HDCP 2.1 for 4k content. Sony 4k TVs only support HDCP 1.4.
AACS – Blu-ray’s Content Protection • Design started in 2002 – Sony, Panasonic, Toshiba, Intel, Microsoft, IBM, Disney, Warner Bros • Different security models for CE and IT – Unique device certificates for hardware BD players because CE did not want to have to download new firmware – Shared device certificates for software BD players because cannot securely incorporate unique device certificates in software players • Response to a security breach is to revoke compromised device certificates • High definition analog outputs were permitted – Studios did not want analog outputs because analog outputs cannot be protected – CE needed to accommodate a legacy of several million HD TVs without digital inputs – Compromise was HD analog sunset in December 2010 • Fox disliked AACS so much they introduced BD+
AACS – Breach Management • Breach response is to revoke compromised certificates so that they cannot be used to play AACS content • When a device certificate compromised all Blu-ray discs mastered until that certificate is revoked can be ripped. – This is “hack one, hack all” • Revocation takes 3-6 months including due process for licensee – Revocation only protects discs mastered after the certificate was revoked – If a software player certificate is revoked consumers will have to update software players in order to play new discs. – If a hardware player certificate is revoked the player is bricked (since CE did not want to support renewability) • Makers of commercial ripping software obfuscate the certificates they are using making it very difficult to know which certificate to revoke – Some commercial ripping software is SaaS • Revocation only works at all until someone figures out how to hack a hardware player – When that happens AACS revokes the player certificate, pirate buys a new player, repeat
What do we learn from AACS? AACS What it means for 4k 1. Legacy HDTVs with only analog outputs were accommodated only because all parties wanted HD discs. 1. Since studios aren’t in a hurry for 4k they are unlikely to accept lower security standards in “legacy” 4k products 2. “Hack one, hack all” has to be avoided. 2. Content protection needs to be per-title (or even per account) – no more hack one, hack all 3. Compromised certificates came from weak 3. Third party certification of security implementations software implementations 4. Continuous breach monitoring, rapid breach response, proactive breach response. 4. Revocation does not work: too slow, cannot always tell which certificates to revoke, has an epic fail scenario.
Enhanced Content Protection • Select a security solution provider with a proven track record • Software diversity per title and even per account • Decode in Trusted Execution Environment • Protected right up to the video buffer • HDCP 2.1 required for output • Device keys protected by a Hardware Root of Trust • Require 3rd party verification of trusted DRM software
Breach Management • Security provider monitors Internet (websites, chat rooms, IRC, etc) for indications of security breaches • Security provider works with manufacturers to identify circumventions used by attackers • Countermeasures developed and deployed immediately a breach is detected • Some new content may prevent playback on certain devices until player is up-to- date • “Tracing Traitors” mechanisms to track compromised implementations
Recommend
More recommend
