HDMI notes-from HDMI Wiki

1. pixel clock frequency

The HDMI specification defines the protocols, signals, electrical interfaces and mechanical requirements of the standard.^{[42] The maximum pixel clock rate for HDMI 1.0 was 165 MHz, which was sufficient to support 1080 p and wuxga (1920x1200) at 60Hz. HDMI 1.3 increased that to 340 MHz, which allows for higher resolution (such as wqxga, 2560 × 1600) across a single digital link.[43] an HDMI connection can either be single-link (type A/C) or dual-Link (type B) and can have a video pixel rate of 25 MHz to 340 MHz (for a single-link connection) or 25 MHz to 680 MHz (for a dual-link connection ).}

 

2. Supported video format and audio format. Subtitle is not supported:

To ensure baseline compatibility between different HDMI sources and displays (as well as backward compatibility with the specified ically compatible DVI standard) All HDMI devices must support the sRGB color space at 8 bits per component.^{[48] Support for The YCbCr Color Space and higher color depths ("deep color") is optional. HDMI permits sRGB (8-16 bits per component), xvycc (8-16 bits per component), YCbCr (8-16 bits per component ), or YCbCr (8-12 bits per component ).[49][50] The color spaces that can be used by HDMI are ITU-R bt.601, ITU-R BT.709-5 and IEC 61966-2-4.[49]}

For Digital Audio, if an HDMI device supports audio, it is required to support the baseline format: Stereo (uncompressed) PCM. other formats are optional, with HDMI allowing up to 8 channels of uncompressed audio at sample sizes of 16-bit, 20-bit and 24-bit, with sample rates of 32 kHz, 44.1 kHz, 48 khz, 88.2 kHz, 96 kHz, 176.4 kHz and 192 kHz.^{[20][51] HDMI also supports any IEC 61937-compliant compressed audio stream, such as Dolby Digital and DTS, and up to 8 channels of one-bit DSD audio (used on super audio CDS) at rates up to four times that of super audio CD.[51] With version 1.3, HDMI supports lossless compressed audio streams Dolby truehd and DTS-HD master audio.[51] As with The YCbCr video, Device Support for audio is optional. Audio return channel (ARC) is a feature introduced in the HDMI 1.4 standard.[52] "return" refers to the case where the audio comes from the TV and can be sent "upstream" to the AV receiver er using the HDMI cable connected to the AV receiver.[52] An example given on the HDMI website is that a TV that directly acquires es a terrestrial/satellite broadcast, or has a video source built in, sends the audio "upstream" to the AV explorer.[52]}

The HDMI standard was not designed to pass Closed Caption data (for example, subtitles) to the television for decoding.^{[53] as such, any Closed Caption stream must be decoded and encoded as an image in the video stream (s) prior to transmission over an HDMI cable to be viewed on the DTV. this limits the caption style (even for digital captions) to only that decoded at the source prior to HDMI transmission. this also prevents Closed Captions when transmission over HDMI is required for upconversion. for example, a DVD player that sends an upscaled 720 p/1080i format via HDMI to an HDTV has no way to pass closed captioning data so that the HDTV can decode it, as there is no line 21 VBI in that format.}

 

3. HDMI 1.3 cable definition:

HDMI 1.3 defines two cable categories: category 1-certified cables, which have been tested at 74.5 MHz (which wocould include resolutions such as 720p60 and 1080i60), and category 2-certified cables, which have been tested at 340 MHz (which wocould include resolutions such as 1080p60 and 2160p30 ).^{[62][66][67] category 1 HDMI cables are marketed as "standard" and category 2 HDMI cables as "high speed ".[1] This labeling guideline for HDMI cables went into effect on October 17,200 8}

 

4. HDMI 1.4 cable definition:

• Standard HDMI cable-up to 1080i and 720 p
• Standard HDMI cable with Ethernet
• Automotive HDMI cable
• High Speed HDMI cable-1080 p, 4 K, 3D and deep color
• High Speed HDMI cable with Ethernet

 

5. DDC

The display data channel (DDC) is a communication channel based on the i² C bus specification.^{[81][82] HDMI specifically requires support for the enhanced display data channel (E-DDC ), which is used by the HDMI source device to read the E-EDID data from the HDMI sink device to learn what audio/video formats it supports.[78][81][82] HDMI requires that the E-DDC support i² C standard mode speed (100 kbit/s) and allows optional support for fast mode speed (400 kbit/s ).[83]}

The DDC channel is actively used for high definition content protection.

 

6. CEC

Consumer Electronics Control (CEC) is an HDMI feature designed to allow the user to command and control up-to ten CEC-enabled devices, that are connected through HDMI,^{[92][93] by using only one of their remote controls (for example by controlling a television set, set-top box, and DVD player using only the remote control of the TV ).[94] CEC also allows for individual CEC-enabled devices to command and control each other without user intervention.[94][95][96][97][98][99][100]}

It is a one-wire bidirectional serial bus that uses the industry-standard Av. Link Protocol to perform remote control functions. CEC wiring is mandatory, although implementation of CEC in a product is optional.

Trade names for CEC are anynet + (Samsung); Aquos Link (sharp); bravia link and bravia sync (Sony); HDMI-CEC (HITACHI); e-Link (AOC ); kuro Link (Pioneer); Ce-link and regza Link (toshba); rihd (remote interactive over HDMI) (onmtr); runcolink (runco International); simplink (LG ); hdavi control, ez-sync, Viera Link (Panasonic); EasyLink (Philips); and netcommand for HDMI (Mitsubishi ).^{[109][110][111][112][113]}

The following is a list of HDMI-CEC commands:

• One touch play:Allows devices to switch the TV to use it as the active source when playback starts
• System standbyEnables users to switch multiple devices to standby mode with the press of one button
• Preset transfer:Transfers the tuner channel setup to another TV set
• One touch recordAllows users to record whatever is currently being shown on the HDTV screen on a selected recording device
• Timer ProgrammingAllows users to use the electronic program guides (EPGs) that are built into initialize HDTVs and Set-Top-boxes to program the timer in recording devices like pvrs and DVRs
• System Information:Checks all components for bus addresses and Configuration
• Deck ControlAllows a component to interrogate and control the operation (play, pause, rewind etc.), of a playback component (Blu-ray or hd dvd player or a camcorder, etc .)
• Tuner ControlAllows a component to control the tuner of another component
• OSD display:Use the OSD of the TV set to display text
• Device Menu ControlAllows a component to control the menu system of another component by passing through the user interface (UI) commands
• Routing control:Control the switching of signal sources
• Remote Control pass throughAllows remote control commands to be passed through to other devices within the system
• Device OSD name transfer:Transfer the preferred device names to the TV set
• System audio controlAllows the volume of an AV consumer er, integrated amplifier or pre-amplifier to be controlled using any remote control from a suitably-equipped device (s) in the system

 

7. Arc and HEC (1.4 defined)

Arc can route the audio route in HDMI to the AV Amplifier, saving a line (connecting the media source to the amplifier ). With CEC, a good blueprint is to connect all devices through HDMI, and then everything is done.

HDMI 1.4 introduces two features called arc (audio return channel) and HEC (HDMI Ethernet channel ).^{[79][80][114] These features use two pins from the connector: A previusly unused pin and the hot plug detect pin.[114]}

ARC is an audio link meant to replace other cables between the TV and the/V runner er or speaker system.^{[79] this direction is used when the TV is the one that generates or has es the video stream instead of the other equipment.[79] a typical case is the partition tion of ATSC or DVB signals by a TV, but reproduction of audio is handled by the other equipment.[79] without arc, the audio output from the TV needs to be routed by another cable, typically TOS-link or coax, into the speaker system.[79]}

HEC provides a bidirectional Ethernet communication at 100 Mbit/s.^{[80] It also goes by the name heac (HDMI, Ethernet, audio, control ).[114]}