HDCP Management
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High-bandwidth Digital Content Protection (HDCP) Management

Introduction to HDCP

HDCP is an industry-adopted specification for the protection of high-value entertainment media on digital video interfaces. HDCP-encrypted content is not allowed playback on video systems that do not conform to the specification, which often creates difficulties in Pro AV deployments. The addition of HDCP management functionality to Tesira software will allow TesiraLUX devices to support playback of protected content. TesiraLUX also intelligently manages the HDCP topology to reduce the risk of the protected source blanking content to the entire system.

For a more detailed description of HDCP, click on the following link support.bimap.com and search for "HDCP."

HDCP Topology Considerations

There are two predominate versions of HDCP currently. Each version of HDCP uses differing topology limitations for the maximum number of devices, level of repeaters, network transport and if content is allowed down-conversion to a previous HDCP version. See the following table for a description of HDCP capabilities:

HDCP Version

 Network Transmission

Maximum Devices

 Maximum Levels UHD Output to HDCP 1.4
HDCP 1.4

No

128

7

No

Yes
HDCP 2.2 - Type 0

Yes

32

4

No

Yes
HDCP 2.2- Type 1

Yes

32

4

Yes

No

Maximum Devices and Levels

In HDCP terms, devices are classified as sources, repeaters or receivers. For example, a media player is a source, an HDMI splitter is a repeater and a television is a receiver.

Per the HDCP rules and regulations, each protected HDCP 2.x source is allowed 32 downstream devices across a maximum repeater depth level of 4. The depth count starts at the first repeating device. TesiraLUX encoders and decoders are HDCP repeaters. The network is not included in the device or level limits. A simple system of source, encoder, two decoders and two displays are a count of 5 devices with a level depth of 3.

Once the connected devices exceed the maximum devices or levels allowed by the standard, the source will deny playback of protected media. TesiraLUX intelligently manages where content is allowed so overage conditions are mitigated.

Network Transmission

Network transmission is only allowed under HDCP 2.x protection. HDCP 1.x is not allowed over the network according to the HDCP specifications. In TesiraLUX, any HDCP protected input source is converted to HDCP 2.2 for network transmission. This means the maximum number of devices supported for each source is 32 with repeater device levels of 4, regardless of the input HDCP version. This translates to a fanout limit of 15 decoders depending on downstream devices outside the Tesira system.

UHD Type 1 Content

HDCP 2.2 “Type 0” protected content may be output to a HDCP 2.x or downgraded to a HDCP 1.x receiver. The owners of high-value content may opt to enable HDCP 2.2 “Type 1” support on the media (common on UltraHD Blu-ray discs).

HDCP 2.2 Type 1 content is not allowed to be down-converted to previous standards and must be shown on a HDCP 2.2 receiver. A display having only HDCP 1.4 support is not allowed to display HDCP 2.2 Type 1 content. Only “Type 0” content is allowed down-converted as needed to support the attached display system.

Managing HDCP in Tesira

When designing a system that includes inputs/outputs that will stream HDCP content, a user will be required to allow the TesiraLUX devices (IDH-1; OH-1)  to enable HDCP content.

HDCP functionality is managed from a single location and can be accessed throughout the Tesira software by clicking the shield icon from any of the following locations:

HDCP may also be enabled/disabled individually from the Control Dialog of Input or Output tabs of the AV Input or AV Output DSP blocks, respectively.

Clicking the HDCP management button will bring up the following window which lists all blocks in all partitions with HDCP functionality:

Each block's HDCP state may be toggled individually, in groups or en masse. By choosing "Select All" prior to enabling or disabling HDCP, all selected blocks will be enabled/disabled.

Design Considerations

Output Prioritization

Tesira software sets the priority by which output devices (monitors) connected to the system receive fast switching for streaming HDCP content. For nearly instantaneous protected stream switching, the following limits are observed:

More than 32 devices may be connected in a system, but once priority is set, any devices that fall outside that priority require a moment to re-authenticate and stream HDCP content if stream routes are changed.

Devices downstream of the TesiraLUX system also count toward the 32 device and 4 level limits required by the HDCP regulations. TesiraLUX will factor this in to the output prioritization and deny content to outputs that exceed the limitations to prevent source blackouts.

HDCP priority is determined for each AV block by several factors when designing a system in Tesira software. Priority is determined in the following order:

  1. The number of signal path segment hops.
  2. Connections from lower AV Router block output port numbers prioritized over connections from higher output port numbers.
  3. If the previous factors are equal, priority is determined alphanumerically based on the AV Output block label text.
  4. If the previous three factors are equal, priority is determined by the block Object ID

Examples of the priorities are as follows:

Priority 1:

Out 1 takes priority over Out 2 as there is only one segment in the signal path between AV Input and Out 1

Priority 2:

The line segments are equal, but the AVRouter outputs originate from different output ports, thus Out Port 1 takes priority over Out Port 2 simply because the number 1 comes before the number 2.

Priority 3:

The line segments are equal and there's no AVRouter in between the input and outputs to determine priority, thus Out 1 takes priority over Out 2 due to alphanumeric determination.

 

Priority 4:

Both outputs are connected directly to the same port, both have one line segment and have the same name, yet are prioritized by the unique object codes (02 taking priority over 03).

 

Priorities calculated by the software can be viewed by expanding the Output Priority of any AV Output as shown in the HDCP Management window below:

In this example all input blocks connected to this output treat the output block as the first priority for fast stream switching for both video and audio streams.

HDCP Connection Persistence

To prevent dropouts at the media source, TesiraLUX units will attempt to maintain HDCP authentication sessions on as many peers as possible, while preventing limit overages, based on the considerations in the sections that follow.

OH-1

The OH-1 prevents topology changes from causing blackouts on upstream devices when encryption is active:

A saved topology is reset to the current topology when one of the following occurs:

The presence of any of the above scenarios may cause temporary audio and video dropouts while HDCP topologies are propagated to the protected source. Additionally, turning a connected display on or off may also cause topology changes/blackouts depending on display behavior.

Blackout Behavior Potential Cause
No Audio/Green Screen OH-1 does not have a session key
Type 1 content received by OH-1 and downstream device is not HDCP 2.2 or greater
Device is not in the priority list determined by Tesira software

 

Any OH-1 that has more than 30 downstream devices or more than three repeater device depth levels will not authenticate with an IDH-1 as the device count will exceed 32, the depth level will be four and thus exceed the HDCP 2.2 limitations.  

IDH-1

The IDH-1 maintains a list of devices that are chosen to authenticate for HDCP. This list is updated any time an event occurs that may change the list contents, such as:

Device Limit Examples

There are numerous combinations of sources and outputs that can be achieved with TesiraLUX to support HDCP content. Below are several examples of designs that allow HDCP content to stream to all output displays as well as designs that have flaws (device depth and device count exceeded).

Example 1 (All Displays Showing HDCP Content)

This example has a total of 31 devices, one less than the maximum allowed under HDCP 2.2 (Types 0 and 1). The device depth count is three (count starts at the IDH-1 encoder).

 

Example 2 (All Displays Showing HDCP Content)

This example is nearly identical to Example 1 except a 2nd HDCP source is added. This adds one additional device to the HDCP count (32) which is the maximum allowed. The device depth count is still three.

Example 3 (No Displays Showing HDCP Content)

In this example the device count is well below the allotted limit, yet the displays will not show HDCP content as the device depth is too high. The HDMI Extend Tx will be device one and therefore the displays would be device six, which exceeds the HDCP 2.2 depth-limit of four.

Example 4 (One Display Not Showing HDCP Content)

In this example the device depth is within HDCP 2.2 limits at three, yet the device count is 33, therefore the final display in the design will not show HDCP content.

Refer back to Output_Prioritization for design considerations when device counts may be exceeded.