Loss-of-Video Failover Protection with This Easy Trick

Many TelVue systems include a Blackmagic Design SDI to Analog Mini Converter (pictured on right) as the signal heads out to cable1. A key feature of the SDI to Analog Mini Converter is the ALT SDI IN (❷). This alternate input provides the ability to have a loss of video fail-safe, should your playback server lose power.

How Does It Work?

When using both the SDI IN (❶) and ALT SDI IN, the ALT SDI IN will immediately take over, should the SDI IN signal fail or no longer be present. The SDI LOCK LED will flash, indicating that the Mini Converter has switched to the ALT SDI IN. (In its normal state, the LED is solid white.) It is important to note that the failover will only occur if a loss of SDI input is detected. If a valid signal that is just black frames or freeze frame is present, that will not cause a failover. Dedicated failover protection switchers may be employed if you require more sophisticated failover detection.

Returning to Primary SDI Input

Once the primary SDI source is restored, the SDI to Analog Mini Converter will not auto failback to the primary source. To restore the primary SDI source:

  1. Ensure there is a valid signal plugged into the primary SDI IN on the SDI to Analog Mini Converter.
  2. Force a loss of signal on the ALT SDI IN. There are a few ways to do this including:
    1. Temporarily disconnect the SDI cable from the ALT SDI IN for 30 seconds (to play it safe) on the SDI to Analog Mini Converter. Make sure to plug it back in once Primary is restored.
    2. Reboot the device plugged into the ALT SDI IN so that it forces a temporary loss of signal.
  3. Once restored, the LED should stop blinking and return to a solid state on the SDI to Analog Mini Converter. You should see that the converter output is now sending your Primary signal.

Using InfoVue As Failover

If an InfoVue system is integrated with a playback server using SDI baseband via a HDMI to SDI Micro Converter, it’s possible to configure that as the auto failover source2. The HDMI to SDI Micro Converter has two SDI outputs (❶ and ❷), allowing for one output to feed an SDI input on the playback server and the other to provide a signal to the ALT SDI IN on the SDI to Analog Mini Converter. When an InfoVue provides the failover signal to the SDI to Analog Mini Converter, instead of disconnecting the SDI cable to the ALT SDI IN, you can reboot the InfoVue to force the backup signal to be lost and restore the primary source. If using an InfoVue Pro or Standard player for example, you can use the InfoVue Web UI to reboot.

If you would like to use a single source to provide the ALT SDI IN for multiple Mini Converters (multiple channels), you can consider using an SDI Distribution Amplifier to get multiple SDI outputs of the same source.

1Some systems include audio adjustment equipment or distribution amplifiers before cable handoff.

2Customer must also have SDI to Analog Mini Converter with ALT SDI IN. Some customers are able to directly feed SDI out of their playback system into cable equipment.

in HC FAQs

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