HDMI Explained
HDMI 1.1:
- Added support for DVD Audio.
HDMI 1.2:
- Adds features that increase the HDMI Specification’s offering for use in both the CE and PC industries. Features and modifications for HDMI 1.2 include: Support for One Bit Audio format, such as SuperAudio CD’s DSD (Direct Stream Digital), changes to offer better support for current and future PCs with HDMI outputs, including: availability of the widely-used HDMI Type A connector for PC sources and displays with full support for PC video formats, ability for PC sources to use their native RGB color space while retaining the option to support the YCbCr CE color space, requirement for HDMI 1.2 and later displays to support future low-voltage (i.e., AC-coupled) sources, such as those based on PCI Express I/O technology.
HDMI 1.2a:
- Consumer Electronic Control (CEC) features and command sets and CEC compliance tests are now fully specified.
- Significantly, CTS 1.2a contains additional cable and connector testing and Authorized Testing Center (ATC) submission requirements. Specifically, under CTS 1.2a, the Adopter shall submit for testing to the ATC any new HDMI cable whose length exceeds previously tested cables.
- Creation of version 1.2a of the HDMI Compliance Test Specification (CTS), which includes a CEC Supplement. HDMI CTS 1.2a has been updated for technical consistency with HDMI Specification 1.2a as well as to the recently released HDMI Specification 1.2.
- Additionally, HDMI Licensing, LLC will maintain a list of approved connectors. For a device to pass CTS 1.2a testing at an ATC, all connectors on such device must appear on the approved connector list. To add a connector to this list, the vendor must submit to the ATC or HDMI Licensing, LLC full and passing testing results.
HDMI 1.3:
- Higher speed: HDMI 1.3 increases its single-link bandwidth to 340 MHz (10.2 Gbps) to support the demands of future HD display devices, such as higher resolutions, Deep Color and high frame rates. In addition, built into the HDMI 1.3 specification is the technical foundation that will let future versions of the HDMI Specification reach significantly higher speeds.
- New mini connector: With small portable devices such as HD camcorders and still cameras demanding seamless connectivity to HDTVs, HDMI 1.3 offers a new, smaller form factor connector option.
- Deep Color: HDMI 1.3 supports 10-bit, 12-bit and 16-bit (RGB or YCbCr) color depths, up from the 8-bit depths in previous versions of the HDMI specification, for stunning rendering of over one billion colors in unprecedented detail.
- Broader color space: HDMI 1.3 adds support for “x.v.Color™” (which is the consumer name describing the IEC 61966-2-4 xvYCC color standard), which removes current color space limitations and enables the display of any color viewable by the human eye.
- New HD lossless audio formats: In addition to HDMI’s current ability to support high-bandwidth uncompressed digital audio and all currently-available compressed formats (such as Dolby® Digital and DTS®), HDMI 1.3 adds additional support for new lossless compressed digital audio formats Dolby TrueHD and DTS-HD Master Audio™.
- Lip Sync: Because consumer electronics devices are using increasingly complex digital signal processing to enhance the clarity and detail of the content, synchronization of video and audio in user devices has become a greater challenge and could potentially require complex end-user adjustments. HDMI 1.3 incorporates automatic audio synching capabilities that allows devices to perform this synchronization automatically with total accuracy.
HDMI 2.0: significantly increases bandwidth to 18Gbps and includes the following advanced features:
- Resolutions up to 4K@50/60 (2160p), which is 4 times the clarity of 1080p/60 video resolution, for the ultimate video experience
- Up to 32 audio channels for a multi-dimensional immersive audio experience
- Up to 1536kHz audio sample frequency for the highest audio fidelity
- Simultaneous delivery of dual video streams to multiple users on the same screen
- Simultaneous delivery of multi-stream audio to multiple users (Up to 4)
- Support for the wide angle theatrical 21:9 video aspect ratio
- Dynamic synchronization of video and audio streams
- CEC extensions provide more expanded command and control of consumer electronics devices through a single control point
HDCP Explained
High-bandwidth Digital Content Protection (HDCP), is a form of digital copy protection developed by Intel Corporation[1] to prevent copying of digital audio and video content as it travels across connections. Types of connections include DisplayPort (DP), Digital Visual Interface (DVI), and High-Definition Multimedia Interface (HDMI), as well as less popular, or now defunct, protocols like Gigabit Video Interface (GVIF) and Unified Display Interface (UDI).
The system is meant to stop HDCP-encrypted content from being played on unauthorized devices or devices which have been modified to copy HDCP content. Before sending data, a transmitting device checks that the receiver is authorized to receive it. If so, the transmitter encrypts the data to prevent eavesdropping as it flows to the receiver.[4]
In order to make a device that plays material protected by HDCP, the manufacturer must obtain a license from Intel subsidiary Digital Content Protection LLC, pay an annual fee, and submit to various conditions. For example, the device cannot be designed to copy; it must “frustrate attempts to defeat the content protection requirements”; it must not transmit high definition protected video to non-HDCP receivers; and DVD-Audio material can be played only at CD-audio quality by non-HDCP digital audio outputs (analog audio outputs have no quality limits).
Cryptanalysis researchers demonstrated flaws in HDCP as early as 2001. In September 2010, an HDCP master key that allows for the generation of valid device keys—rendering the key revocation feature of HDCP useless—was released to the public. Intel has confirmed that the crack is real, and believes the master key was reverse engineeredrather than leaked. In practical terms, the impact of the crack has been described as “the digital equivalent of pointing a video camera at the TV”, and of limited importance for copyright infringers because the encryption of high-definition discs has been attacked directly, with the loss of interactive features like menus. Intel threatened to sue anyone producing an unlicensed device.