Video Formats and Terms- DVI and EDID
Digital Video Interface. This is the digital version of a computer signal. The color components (Red, Green and Blue) each carry their own luminance values. This results in what is called a 4:4:4 signal sampling where each component is sampled twice. Two samples for color and two samples for luminance. This type of color processing allows for a broader range of colors than what is available in HD Video.
DVI uses 8-bit processing. The distance you can run DVI over copper wire is limited to about 5M (15ft). There are longer DVI copper cables available, but will not be usable the higher you go in resolution. For anything of distance, DVI to fiber or DVI to Cat5 solutions are available.
DVI is characterized by the following:
- Single Link
- Can handle pixel clocks up to 165MHz
- Max resolution [email protected]
- Dual Link
- Two channels of up to 2048x1080 each that produce higher resolutions
- Read jacket of cable to insure is is dual link. Some manufacturers have used dual link connector on single link cable.
- DVI-I (Integrated)
- Contains an analog version of the signal
- The analog output is transmitted on the four pins around the ground blade
- The Event Master Series DVI cards have a DVI-I connector. However, there is no analog signal available as an input or output.
- DVI-D (Digital Only)
- The connector will only have the digital version of the signal
- On monitors or display devices, this connector will only accept digital signals
Some the failings of the DVI connector have been easy damage to the pins, bulkiness of the connector and limited number of insertions. The DVI connector is only rated for about 500 insertions before it should be replaced.
Extended Display Identification Data
A display's native resolution is transmitted to a computer's graphic card. The card then automatically configures itself for that resolution.
On the E2/S3-
- Input EDIDs can be programmed per connector or globally
- Custom EDIDs can be programmed
- On the outputs, the EDID can be read from an attached display device and the output format automatically set
- The default EDID is 1920x1080p
- Higher resolution EDIDs may not be available if the connector capacity has not been properly set
EDID is not the same thing as HDCP.
One problem encountered with EDID is if the output cable is removed once the resolution is set, the graphic card may default to lower resolution and stop outputting completely. This may require a restart of the computer to re-establish the EDID connection.
A means of avoiding this is to have EDID managers or a EDID capture device connected to the computer outputs at all times.
Name that DVI Connector
- DVI-D Single Link
- DVI-I Dual Link
- DVI-I Single Link
- DVI-D Dual Link
The factory default EDID setting on an E2/S3 is?
Video Formats and Terms- HDMI and HDCP
This is a consumer format connector that has found its way into professional applications. The original use was to be able to connect a Blu-Ray player and HD flatscreen with one cable; giving the user HD video and digital audio simultaneously.
One of the connector's drawbacks is it has no locking mechanism. There are ways to secure the connector with a slide-over headshell and screw. The E2/S3 have a threaded stand-off that on the HDMI connectors that fits this screw.
- HDMI 1.4a
- This is the standard currently support on the HDMI connections for E2 and S3
- Allows for 4K signals @30 refresh over a single cable
- Support for up to [email protected]
- HDMI 2.0
- This standard is required for 4K @60 refresh over a single cable
- There will be an all HDMI input and output card released in the future that supports this standard
Over copper cable, a 1080p signal can travel about 15m (50ft). Be sure to use "high-speed" HDMI cables. There are also fiber and Cat5/6 options for going farther.
The bane of any video technicians existence.
When Blu-Ray and HD-DVD were set to release, the studios in Hollywood wanted a measure of protection to discourage illegal copying of what is essentially a digital master of their films. A consortium of content owners and hardware manufacturers came up with HDCP (High-Bandwidth Digital Content Protection).
The implementation was to be this; a Blu-Ray author would enable a "flag" in the programming of the disc that would tell the hardware player to check for HDCP compliance. If all detected devices in the chain were compliant, then show the movie. How this ended up being implemented was that the hardware manufacturers turned HDCP on all the time, regardless of whether the content was HDCP encrypted or not.
Any manufacturer with a device that has a HDMI connector is suppose to pay a licensing fee and abide by the HDCP rules. Anyone not doing so, or disabling HDCP, may be blacklisted and the information for that device gets included in file that is burned into the HDMI transmit/receive chips. If that device is detected, all output is turned off.
A current trend is for presenters to want to display there iPads, tablets or smartphones as part of their presentation. HDCP makes this very difficult as these devices often have output adapters that convert to HDMI.
- HDCP is supported on HDMI, DisplayPort and DVI
- HDCP is not supported on analog (VGA) or HD-SDI (BNC) connectors
- HDCP 2.2
- Recently released, this form of HDCP is for the protection of streaming 4K content
- It is not backwards compatible with previous HDCP versions
- People with older 4K televisions may not be able view streaming from cable systems or internet services
HDCP- Your friend in the digital age...
HDCPHigh-Bandwidth Content Protection
HDCP 2.2Encryption for UHD 4K streaming content
A MacBook will not display any content.It is connected to a HDCP compliant distribution amp (DA) and one of the detected devices is not HDCP compliant.
HDCP is not supported.Analog and HD-SDI
Video Formats and Terms- HD-SDI
Serial Digital interface. This video format is based on standards set by SMPTE (Society of Motion Picture and Television Engineers). Since it is standardized, there are a limited amount of resolutions available. This also means that when connecting two SDI capable devices, there is a higher chance of success.
The variations are:
- HD-SDI (SMPTE 292M)
- Supports 720p and 1080i/p resolutions
- 1080p is supported up to 30Hz refresh
- 8 channels of embedded AES digital audio
- 3G-SDI (SMPTE 424M)
- Supports 720p and 1080i/p resolutions
- 1080p is supported up to 60Hz refresh
- 8 channels of embedded AES digital audio
- Developed by BARCO to fit within the 3G HDSDI specification
- [email protected] on a standard HD-SDI coax cable
- No longer need DVI fiber cable to transport signal over distance
- Supports native resolution of current BARCO Events series projectors
- 6G-SDI (SMPTE Preliminary ST-2036)
- Not ratified as a standard
- Adds support for UHD 4K ([email protected])
- E2 and S3 HD-SDI connectors are rated for 6G HD-SDI
- Format will be added when SMPTE standard is released
- Adds UHD 4K @ 60Hz
All SDI formats suffer from the same inherent problem of the "digital cliff." The video signal itself is just ones and zeroes. A reclocking signal is an analog pulse that helps keep the digits in order. Since it is analog and tied to a voltage, the signal will weaken over distance. The "digital cliff" is the point where the reclocking signal is no longer strong enough to maintain the order of the digits. The image falls apart.
A reclocking DA (Distribution Amplifier) is then required to boost the pulse and drive the signal further. The amount of distance a HD-SDI signal can go is related to the resolution being sent and the quality of the coax cable being used. There are no absolutes as to what will give you the longest distance. The same cable that gave you 500 feet of signal last time, may only give you 300 ft this time because you changed the brand of gear at either end. There are some estimates that you can use based on cable manufacturer testing.
Here are some examples using a good, digitally rated RG-6 gauge coax cable:
As you can see, when you double your data rate based on your resolution and refresh, you effectively cut the distance you can run on copper coax cable by a ratio of about half.
Using fiber optics to run your signals, negates this entire chart. A 3G-SDI signal can go as far as a SD-SDI signal. But, fiber optic solutions can be expensive and there is no mixing and matching between manufacturers. Raw coax cable and BNC connectors will still be cheaper and unless you have to run extreme distances, is often the better way to go.
HDSDI- From Point A to B
You have a 720p HDSDI signal that you need to run 200m. Which device below will you need?
You can click on the magnifying glass for a larger image.
Wait a Gigabit....
720 x 480i @ 50Hz270 Mb/sec
1280 x 720p @ 59.94Hz1.2 Gb/sec
1920 x 1080p @ 29.97Hz1.5 Gb/sec
1920 x 1080p @ 60Hz3 Gb/sec
3840x2160 @ 30Hz6 Gb/sec
Video Formats and Terms- DisplayPort
This connector tends to be is used as the digital display output on higher-end laptops and graphics cards. Its list of features:
- 10Gb/sec across four channels
- Latching connector with push button release
- 3m signal distance on passive cables
- Apple "Thunderbolt" is a mini-DisplayPort connector
- Supports HDCP
- Support for 2560x1600 resolution
This connector is legacy compatible with DVI. This usually requires a DisplayPort (DP) to DVI adapter. Take note that there are both active and passive adapters. Active adapters use the 5 volts of the DP port to power electronics inside the DVI connector. They are also slightly more expensive than the passive version. You will find that in most instances, the active adapter is required. Only single link resolutions are supported by these inline style adapters.
For dual-link resolutions (above 2048x1080), you will have to use a DP to DVI-DL adapter. They are always active and have a separate USB connection that is just used to supply power.
DisplayPort also supports UHD 4K resolutions.
- DisplayPort 1.1
- Currently supported on E2 and S3 DP connectors
- Up to UHD 4K @ 30Hz
- DisplayPort 1.2
- An all DP card will be released in the future
- Up to UHD 4K @ 60Hz
On the E2/S3, the DisplayPort inputs only accept DisplayPort signals. You cannot simply adapt HDMI or DVI to DisplayPort and plug it in. This can only be done with an active conversion. These adaptors are usually specified as "xxx to DisplayPort." DisplayPort is directional and therefore you cannot take one of the DP to DVI adaptors mentioned earlier, and use it in reverse.
Below are two examples of ACTIVE converters to the DisplayPort format. The Gefen goes from DVI-Single Link to mini-DisplayPort. It can be externally powered. A mini-DP to full DP cable can then be used to connect to E2/S3.
The Lindy USA device goes from HDMI to DisplayPort and is powered by 5 volts from the HDMI.
Video Formats and Terms- Color Space
This refers to how the color is processed within a video signal. There are typically two general categories:
- Each color component (red, green, blue) has its own luminance value
- Processed as 4:4:4
- Two samples for luminance and two samples for chrominance of each color component
- Can produce more colors
- Luminance is only present on the Y or Green component.
- Generally processed 4:2:2
- Two samples each for luminance and chrominance on the Green channel
- Two samples only of the chrominance for Red and Blue
- Used as the colorspace for HD formats on the HDMI connector
What's wrong with me?
Select the image which correlates to the following scenario:
You have a computer coming in HDMI at 1080p. The input is expecting SMPTE colorspace, but is instead getting RGB.
Input or Output?
Output signal has green mask. I turn on the test pattern color bars and they are also green.The OUTPUT color space needs to be changed.
When I select a computer source, it has magenta mask on my output. I output test pattern color bars and they are fine.The INPUT color space needs to be changed.