Blackmagic Forum

Hello,

I'm using "Scheduled Playback" with success for SDI output on a 8K Pro board - I'm using a playgroup to synchronize the 2 devices on the board, and this works fine.

Now, I'm trying to use the same "Scheduled Playback" and playgroup to synchronize *two* 4K Pro *boards*, each having one device.

All devices report `BMDDeckLinkSupportsSynchronizeToPlaybackGroup = TRUE` but have no genlock.

In this case, my call to `StartScheduledPlayback` fails with the E_FAIL error (0x80004005).

I'm using SDK 11.6, and I saw the same error on multiple machines.

I could not find any limitation description in SDK manual.

What am I missing ?

Anyone has a similar experience ?

Cheers,
N

Hi Nicolas,

It is a requirement when working across multiple cards that each output is locked to reference for Synchronised Playback to start successfully. This check is made by the DeckLink driver and will error if one or more devices in the synchronised playback group is not already locked to reference. Without reference input locking, there will be no relationship of frame timing between outputs on different cards, and so synchronised playback would not work.

When all output devices are on the same card, for example with the DeckLink 8K Pro, it is possible to start synchronised playback without needing to lock to a reference. This is because all outputs enabled with same frame rate will already share the same frame timing.

Regards
Cameron

Hi Cameron,

thanks for your answer ! I was suspecting such a thing, but was not sure.

IMHO this information could be a nice addition to the SDK documentation (if not already in there somewhere !)

Regards,
Nicolas