Chapter 7. Configuring and Using Vela and DVB-ASI Devices

This chapter explains how to install DVB-ASI option boards and the Vela Research four-port MPEG-2 decoder and how to configure the VST server to work with them, in these sections:

Installing the Vela Research MPEG-2 Decoder

For MPEG-2 decoding, VST supports the Vela Research four-port SCSI-attached decoders. These decoders communicate with the VST server over a single-ended or differential fast/wide SCSI bus and decode MPEG-2 transport or program streams to composite analog video.

The Vela decoder supports two kinds of SCSI ports: differential and single-ended. Make sure to use the Vela board that supports your SCSI ports:

  • The built-in external SCSI port on the O2 is single-ended.

  • The Origin 200 system does not have a built-in SCSI port.

  • The SGI MSCSI XIO card has four SCSI ports: port 4 is auto-sensing for single-ended or differential.

  • PCI expansion cards are available for both single-ended and differential SCSI.

VST supports up to three four-port decoders (12 MPEG-2 streams) on each SCSI bus. No other SCSI devices should be attached to the bus that is attached to the Vela decoders.

This section describes how to install and configure the Vela decoder, in the following subsections:

Installing and Connecting the Vela Decoder

Follow these steps to install and connect the equipment:

  1. Install the Vela decoder, following instructions in its manual.

  2. Attach the Vela decoder to a SCSI port on the VST system with a standard SCSI-3 cable.

    Because the decoder does not provide a SCSI loop-through connector, if you are connecting more than one decoder to a single bus, you must use a bus-type cable, usually available as a ribbon cable with four to six SCSI-3 connectors attached.

    Note: Do not use a SCSI-3 cable designed for use inside a computer chassis, because this type of cable is not shielded.

  3. Set the decoder's SCSI ID, following instructions in the Vela documentation.

Configuring the Vela Decoder

To configure the Vela decoder, follow these steps:

  1. As root, enter the following command to ensure that the vst_eoe_sw.vela and vst_eoe_sw.mpeg subsystems are installed.

    # /usr/vtr/bin/vtrswinfo -subsys -short 

    The system responds:

    Installed software:
      vst_eoe (1275521220) (1275521220) (1275521220) (1275521220) (1275521220)
        vst_eoe.sw.base (1275521220)
        vst_eoe.sw.fsmon (1275521220)
        vst_eoe.sw.ftpd (1275521220)
        vst_eoe.sw.mpeg (1275521220) (1275521220)
        vst_eoe.sw.vela (1275521220)

    If necessary, install the Vela and MPEG subsystems as explained in “Installing VST” in Chapter 3.

  2. Verify that the Vela decoders are recognized and contain the correct firmware revision. VST version 1.2 requires firmware revision 4035. Enter

    # /usr/vtr/bin/vtrhwinfo 

    The system responds:

      Platform: Origin 200 (hostname=vcpqa4 serial=)
      Processors: 2x225MHz R10000 (IP27)
      Secondary Cache: 2 Mbytes
      Memory: 512 Mbytes
    Video devices:
      vela_0 (bus=2 unit=7 lun=0 dev=sc2d7l0 firmware=<SCSI Decoder X4 4035>)
      vela_1 (bus=2 unit=7 lun=1 dev=sc2d7l1 firmware=<SCSI Decoder X4 4035>)
      vela_2 (bus=2 unit=7 lun=2 dev=sc2d7l2 firmware=<SCSI Decoder X4 4035>)
      vela_3 (bus=2 unit=7 lun=3 dev=sc2d7l3 firmware=<SCSI Decoder X4 4035>)
      vela_4 (bus=3 unit=9 lun=0 dev=sc3d9l0 firmware=<SCSI Decoder X4 4035>)
      vela_5 (bus=3 unit=9 lun=1 dev=sc3d9l1 firmware=<SCSI Decoder X4 4035>)
      vela_6 (bus=3 unit=9 lun=2 dev=sc3d9l2 firmware=<SCSI Decoder X4 4035>)
      vela_7 (bus=3 unit=9 lun=3 dev=sc3d9l3 firmware=<SCSI Decoder X4 4035>)
    Audio devices:
      - none - 
    Audio input ports:
    Audio output ports:
    Serial ports:
      tty1 (module=1/O200 built-in)
      tty2 (module=1/O200 built-in)

    If the incorrect firmware revision is loaded, refer to the Vela decoder documentation for instructions to load the firmware.

Changing Vela Decoder Port Names

When VST is started, each of the four ports on each decoder is assigned a port name. The names are sequential; for example, if one decoder is attached, the ports are named vela_0, vela_1, vela_2, and vela_3. If a Vela decoder is connected to the next SCSI controller, its ports are vela_4, vela_5, vela_6, and vela_7, and so on.

Adding or removing a SCSI device might change the logical ordering of the decoder ports. You can create a fixed mapping of logical port numbers to physical devices through /usr/vtr/config/vtr_ioconfig.conf. This file functions like the /etc/ioconfig.conf file that IRIX uses to map logical controller numbers to physical hardware devices.

If vtr_ioconfig.conf does not already exist on the VST server, create it with the following:

% /usr/vtr/bin/vtrvclahinv > /usr/vtr/config/vtr_ioconfig.conf 

The file contains one entry for each recognized Vela decoder port (four ports per decoder). For example, one decoder attached to each of two SCSI buses might create the following configuration:

0 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/5/scsi_ctlr/0/target/7/lun/0/scsi
1 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/5/scsi_ctlr/0/target/7/lun/1/scsi
2 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/5/scsi_ctlr/0/target/7/lun/2/scsi
3 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/5/scsi_ctlr/0/target/7/lun/3/scsi
4 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/7/scsi_ctlr/0/target/9/lun/0/scsi
5 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/7/scsi_ctlr/0/target/9/lun/1/scsi
6 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/7/scsi_ctlr/0/target/9/lun/2/scsi
7 /hw/module/1/slot/MotherBoard/node/xtalk/8/pci/7/scsi_ctlr/0/target/9/lun/3/scsi

Each entry includes the logical port number followed by the IRIX hardware graph name for the SCSI LUN associated with each decoder port.

Removing a decoder does not change the logical port numbers associated with the remaining decoder. If decoders are added to the system, their ports are assigned logical port numbers above the highest existing logical port number.

Using the External Sync Reference

You can configure the Vela decoder to sync the output video to an external reference by setting to external. The default value, internal, causes the decoder to generate its own video sync.

Set the sync source control in a device defaults file in the /usr/vtr/config/device-defaults directory. Add the control setting to the file vela to set the sync source or all Vela ports or to the file vela_port to set the control for a specific port, such as vela_1, vela_2, and so on.

You can also set the sync source control dynamically with the MVCP SET command.

Vela Controls and Incompatibilities

Table 7-1 summarizes Vela decoder controls and their default values.

Table 7-1. Vela Controls










For more information about any of these controls, see Appendix A or the vst-controls(5M) man page.

The Vela decoder does not support the following MVCP commands:

  • GOTO

  • JOG (in reverse)

  • SHTL (in reverse)

    SHTL does not provide continuously variable speeds.

Installing and Configuring the DVB-ASI Adapter Board

The Viewgraphics MediaPump is a PCI-based adapter board. It multiplexes MPEG-2 transport streams and transmits them over coaxial cables using the Digital Video Broadcast Asynchronous Serial Interface (DVB-ASI) protocol.

This chapter describes how to install and configure a DVB-ASI adapter board for use with VST. It consists of these sections:

Installing the Adapter Board

The DVB-ASI adapter board requires a full-length PCI slot. These slots are supported on the Origin 200 GIGAchannel system, but not in the O2 chassis. Follow these steps:

  1. Install the adapter board(s) in a PCI slot, following the instructions for installing a PCI board in the Origin200 and Origin200 GIGAchannel Maintenance Guide.

  2. As root, enter the following command to verify that the vst_eoe.sw.dvb-vg and vst_eoe.sw.mpeg subsystems are installed:

    # /usr/vtr/bin/vtrswinfo -subsys -short 

    The system responds:

    Installed software:
      vst_eoe (1275521220) (1275521220) (1275521220) (1275521220) (1275521220)
        vst_eoe.sw.base (1275521220)
        vst_eoe.sw.fsmon (1275521220)
        vst_eoe.sw.ftpd (1275521220)
        vst_eoe.sw.mpeg (1275521220) (1275521220)
        vst_eoe.sw.vela (1275521220)

    If necessary, install the Viewgraphics and MPEG subsystems. The Viewgraphics driver software, mediapump.sw.base, is included with the VST software images and is a prerequisite for installing the vst.sw.dvb-vg subsystem. For more information about installing this software, follow the installation instructions for VST presented in Chapter 3, “Installing Video Server Toolkit.”

    Reboot after installing the subsystems.

  3. To verify that the system recognizes the DVB-ASI board(s), open /etc/ioconfig.conf. This file is automatically generated and maintained; it shows how PCI card slots correspond to DVB-ASI boards in the Origin 200 chassis; for example:

    0 /hw/module/1/slot/io7/xbox_dualxtown/pci/3/Dynamo
    1 /hw/module/1/slot/io1/MotherBoard/pci/5/Dynamo

    The first line says that DVB-ASI 0 is in PCI slot 3 of the Origin 200 GIGAchannel chassis. The second line says that DVB-ASI 1is in PCI slot 5 of module 1 motherhoard.

    The DVB-ASI boards also appear in the hardware inventory (hinv) as Unknown:

    hinv: Unknown type 117 class 12
    hinv: Unknown type 117 class 12

    The software installation for the DVB-ASI board appears as an option in the Inst package that comes with VST. To use the DVB-ASI adapter card, you must install vst_eoe.sw.dvb-asi.

Maximizing Output Streams

To enable the MPEG2 stream splicing capability of the Viewgraphics MediaPump board, set the control to true in the device defaults file, /usr/vtr/config/device-defaults/dvb-asi. You can also set this control dynamically with the MVCP SET command.

To maximize the number of output streams, set the following control: false

The default value is false.

You must change the program ID before cueing a clip. The new program ID remains in effect for that unit even after the clip has finished.

Note: The DVB-ASI board might work without any change to its default configuration. If you have resource conflicts, however, see the Video Server Toolkit Developer's Guide for information on setting specific device controls to enable DVB-ASI playback.

DVB-ASI Time-Delay Server

VST includes an HDTV time-delay server feature that allows you to pause or stop a compressed MPEG-2 transport stream. This feature works in conjunction with the Viewgraphics MediaPump DVB-ASI PCI card.

VST can record a DVB-ASI stream for a predefined length of time. You provide a time delay (expansion) in the output stream with an MVCP STOP command, or by a STOP-CUE-PLAY sequence. For example:

CUE unit in-point
@time PLAY unit 

VST finds the closest possible position before the in point you specify, and starts playing. If the position VST finds is five frames before the in point, play starts five frames before the specified time. Thus the correct frame for the specified time plays.

When the output stream is stopped, it can be cued accurately to continue the playout. Content can be inserted locally, downstream of the decoder.

Supported MVCP Commands

The DVB-ASI adapter board supports only the following MVCP commands:

  • CUE

  • CUER

  • LOAD

  • PLAY

  • REC

  • STOP

  • UNLD