Chapter 4. Setting Up Audio Synchronization

This chapter shows you how to synchronize audio with video when you use the DMediaPro Board in a typical studio configuration with a tape deck.

The following topics are covered:

These configurations allow sample accurate audio/audio and audio/video synchronization.

Synchronizing Audio on an Octane2 Workstation

To synchronize audio on a Silicon Graphics Octane2 V10 or V12 workstation, follow these steps:

  1. Connect a house sync generator to a digital tape deck, as shown in Figure 4-1.

  2. Connect the AES 1/2 output on the digital tape deck to the coaxial digital input (internal audio) on the rear panel of the Octane2.

    This locks the internal audio on the Octane2 to the house sync generator.

    For optimized performance and additional functionality, you can purchase the optional SGI PCI Digital Audio Board and install it in the optional PCI module's half-size slot on the Octane2 rear panel. You can install this half-size board in any of the slots in the PCI module, but you may need to use the two full-size slots in the module for additional requirements, such as fiber channel boards.


    Note: For instructions on installing/removing the optional PCI module and PCI option boards, such as the Digital Audio Board, see your Octane or Octane2 Workstation Owner's Guide, Octane PCI Module Installation Guide, and SGI PCI Digital Audio Board Installation Guide.

    If you install the optional PCI Digital Audio Board, proceed as follows:

    • Connect the provided breakout cable to the DB15 connector on the board.

    • Connect the AES 3/4 output on the digital tape deck to the breakout cable's AES input connector (red wire).

      For more information on the PCI Digital Audio Board and breakout cable, see the SGI PCI Digital Audio Board Installation Guide.


      Note: For the optional AES 3/4 configuration, you must use the latest revision of the PCI Digital Audio Board (PN 030-1649-001 or later).


      Figure 4-1. Synchronizing  Audio on an Octane2 Workstation

      Synchronizing 
Audio on an Octane2 Workstation

Synchronizing Audio on Onyx and Origin Systems

To synchronize audio on SGI Onyx and Origin systems, you need an SGI PCI Digital Audio Board.


Note: The PCI Digital Audio Board is standard equipment on the SGI Onyx 3000 I-Brick. To synchronize audio on an SGI Origin 3000, you must purchase the board and install it in the I-Brick or the optional P-Brick. For the SGI Onyx2 and Origin 2000 systems (when compatible with DMediaPro), the board is optional and must be installed by an SGI field installer.



Warning: To prevent serious physical damage in Onyx and Origin systems, you must use the latest revision of the PCI Digital Audio Board (PN 030-1649-001 or later).

To synchronize audio on SGI Onyx and Origin systems, follow these steps:

  1. Connect a house sync generator to a digital tape deck, as shown in Figure 4-2.

  2. Connect the breakout cable that is included with the PCI Digital Audio Board to the DB15 connector on the board.

  3. Connect the AES 1/2 output on the digital tape deck to the PCI Digital Audio Board breakout cable's AES input connector (red wire).

    For additional functionality, you can purchase a second PCI Digital Audio Board for your system. A second board is an option for all applicable SGI Onyx and Origin systems.


    Note: For instructions on installing PCI boards, such as the Digital Audio Board, see your system owner's guide (Onyx 3000 and Origin 3000 only).

    If you have a second PCI Digital Audio Board installed, proceed as follows:

    • Connect the provided breakout cable to the DB15 connector on the second board.

    • Connect the AES 3/4 output on the digital tape deck to the breakout cable's AES input connector (red wire) on the second board (see Figure 4-2).

      For more information on the PCI Digital Audio Board and breakout cable, see the SGI PCI Digital Audio Board Installation Guide.

      Figure 4-2. Synchronizing Audio on Onyx and Origin Systems

      Synchronizing Audio on Onyx and Origin Systems

Setting Up the Audio Panel

For the configurations shown on the previous pages, you can use the Audio Panel to display the AES device controls, set the default input and output to AES I/O, set the audio signal path to AES I/O, and set the output sync source.

Displaying AES Device Controls

To display the AES device controls, follow these steps:

  1. Open the Audio Panel.

  2. From the Toolchest, select Desktop > Control Audio.

  3. Select the desired AES device control panel from the View menu.

    The selected device control panel appears, where you can adjust parameters such as sample rate, input source, and output destination. For details, refer to the Audio Panel Help menu.

Setting the Default Input and Output to AES

The Audio Panel displays device controls for ADAT In, ADAT Out, AES In, and AES Out for each PCI Digital Audio Board installed in your system. You can designate any of these devices as a default, which means your system uses the device as the internal audio device unless otherwise specified by another application. To set the default input and output, simply open the Audio Panel and select a default input and output device in the Default menu.

Setting the Input and Output Signal Path

You can select either electrical or optical signal paths for the AES input and output devices. To set the input source with the Audio Panel, follow these steps:

  1. Position the cursor over the input device panel (if the device panel you need is not displayed, use the View menu), then hold down the right mouse button to display the menu for the desired input device.

  2. Select Preferences in the input device menu.

    The Preferences menu appears for the respective input device.

  3. Choose the input source (for example, AES In) that you want the input device to use. “AES In” is the electrical input.

To set the output destination with the Audio Panel, follow these steps:

  1. Position the cursor over the output device panel (if the device panel you need is not displayed, use the View menu), then hold down the right mouse button to display the menu for the desired output device.

  2. Select Preferences in the output device menu, as shown in Figure 4-3.

    The Preferences menu appears for the respective output device, as shown in Figure 4-4.

  3. Choose the output destination (for example, “AES Out”) that you want the output device to use. “AES Out” is the coaxial digital electrical output.

    Selecting the optical input or output for AES disables the ADAT input or output, because the two devices share the same optical connector. Similarly, selecting the optical input or output for ADAT automatically switches the AES input or output to the coaxial digital electrical connector.

    If more than one PCI Digital Audio Board is installed, the system names each board using an incremental prefix naming scheme. For this type of configuration, one AES input is displayed as “RAD 1.AES In” and the other as “RAD 2.AES In.” Also, one AES output is displayed as “RAD 1.AES Out” and the other as “RAD 2.AES Out (see Figure 4-3).

Setting the Output Sync Source

To set the output sync source, follow these steps:

  1. Position the cursor over the output device panel (if the device panel you need is not displayed, use the View menu), then hold down the right mouse button to display the menu for the desired output device.

  2. Select Preferences in the output device menu, as shown in Figure 4-3.

    The Preferences menu appears for the respective output device, as shown in Figure 4-4.

    Figure 4-3. Selecting Preferences for the Output Device

    Selecting 
Preferences for the Output Device

  3. Choose the sync source that you want the output device to use.

    The example in Figure 4-4 shows how to set up the configuration displayed in Figure 4-1 for synchronizing the Octane2 internal audio using the AES input.

    Figure 4-4. Synchronizing the Octane2 Internal Audio

    Synchronizing the Octane2 Internal Audio

The example in Figure 4-5 shows how to set up the single board configuration shown in Figure 4-2 for an Onyx or Origin system.

Figure 4-5. Synchronizing a Single PCI Digital Audio Board on an Onyx or Origin System

Synchronizing a Single PCI Digital Audio Board on an Onyx or Origin System

The example in Figure 4-6 shows how to set up the RAD 1.AES Out Preferences for the two-board configuration (Figure 4-2) on an Onyx or Origin system.

Figure 4-6. Synchronizing Two PCI Digital Audio Boards on an Onyx/Origin System (RAD 1.AES Out Preferences)

Synchronizing Two PCI Digital Audio Boards on an Onyx/Origin System (RAD 1.AES Out Preferences)

The example in Figure 4-7 shows how to set up the RAD 2.AES Out Preferences for the two-board configuration (Figure 4-2) on an Onyx or Origin system.

Figure 4-7. Synchronizing Two PCI Digital Audio Boards on an Onyx/Origin System (RAD 2.AES Out Preferences)

Synchronizing Two PCI Digital Audio Boards on an Onyx/Origin System (RAD 2.AES Out Preferences)

Other Configurations

The DMediaPro Board does not support audio synchronization using “Internal Video” as a “Sync Source” in the Audio Panel AES or ADAT “Out Preferences” or the Analog “In/Out Preferences.”

In addition to the examples described earlier in this chapter, there are other optional configurations. For example, you can synchronize the PCI Digital Audio Board's audio input to a house sync generator as follows:

  1. Connect the house sync generator to one of the breakout cable's video reference loop connectors (green or black wires).

    If you are not using the other video reference loop connector to loop the video reference signal through another device, place a 75-ohm terminator on the unused connector.

  2. Open the Audio Panel, hold down the right mouse button on the desired output device, select Preferences in the output device menu, and then select Video as the Sync Source.


    Note: To synchronize a digital audio (AES or ADAT) input to a video reference, the input must be synchronized externally because it is externally sampled. The examples described earlier in this chapter (using a tape deck) reflect this requirement.