Key and Fill out of sync decklink (same card)

[CuriousJames]

Hello all,

I'm using CasparCG 2.2 to playout graphics for a student TV station, we're using a Blackmagic Decklink card (I believe it's a Duo 2).

We're just using two SDIs on it - for Fill and Key output to our ATEM which then adds it to the mix.

I've seen on the forum that some say the sync between key and fill is only possible on the 4K Extreme card, but having spoken with Blackmagic support they don't see why this would be the case, so I wondered if this could be cleared up by you guys, please? ...we'd really rather not have to buy a more expensive card if we can help it.

The config we're using is below.

Thanks!

<configuration>
  <paths>
    <media-path>F:\Media\</media-path>
    <log-path>log\</log-path>
    <data-path>data\</data-path>
    <template-path>F:\Templates\</template-path>
    <thumbnails-path>F:\Thumbnails\</thumbnails-path>
  </paths>
  <auto-deinterlace>false</auto-deinterlace>
  <channels>
    <channel>
        <video-mode>1080i5000</video-mode>
        <consumers>
                <decklink>
                    <device>1</device>
                    <key-device>2</key-device>
                    <embedded-audio>false</embedded-audio>
                    <channel-layout>stereo</channel-layout>
                    <latency>normal</latency>
                    <keyer>default</keyer>
                    <key-only>false</key-only>
                    <buffer-depth>5</buffer-depth>
                    <custom-allocator>true</custom-allocator>
                </decklink>
                <decklink>
                    <device>2</device>
                    <embedded-audio>false</embedded-audio>
                    <channel-layout>stereo</channel-layout>
                    <latency>normal</latency>
                    <keyer>default</keyer>
                    <key-only>true</key-only>
                    <buffer-depth>5</buffer-depth>
                    <custom-allocator>true</custom-allocator>
                </decklink>
        </consumers>
    </channel>
  </channels>
  <controllers>
    <tcp>
        <port>5250</port>
        <protocol>AMCP</protocol>
    </tcp>
  </controllers>
  <amcp>
    <media-server>
      <host>localhost</host>
      <port>8000</port>
    </media-server>
  </amcp>
</configuration>```

[Julusian]

The duo2 supports outputting f&k natively, and doesnt need 2 entries in the config. In the decklink configuration software, set the ports of the first channel to 1&3 And use the following config for your consumers:

        <consumers>
                <decklink>
                    <device>1</device>
                    <embedded-audio>false</embedded-audio>
                    <channel-layout>stereo</channel-layout>
                    <latency>normal</latency>
                    <keyer>external</keyer>
                    <key-only>false</key-only>
                    <buffer-depth>5</buffer-depth>
                    <custom-allocator>true</custom-allocator>
                </decklink>
        </consumers>

[CuriousJames]

So, just to confirm you're sayig this will put Fill and Key down one SDI, then using Blackmagic software you can duplicate that output to another SDI out?

If so can you confirm which Blackmagic Software to use please? I see there's the Desktop Video Setup (which I've just upgraded to v11 now) and Multibridge, but neither seem to give me the option to output one channel to two SDIs.

Also only two devices show in Video Setup 'Decklink SDI (1)' and 'Decklink SDI (2)' which makes me think perhaps it's actually a Decklink DUO and not a Decklink DUO 2, I just took the card out to check and it does indeed confirm it's only a Decklink DUO, so does that mean we can't get the key and fill to sync or is that still possible?

Thanks!

[CuriousJames]

Also just as another note, I've found that if I remove the '2' line then it is more in sync, but drifts out and back in sync from time to time.

Another point to note is that the Decklink Duo is plugged into a PCIex8 slot, with the Nvidia GFX card plugged into a PCIex16 slot, would there be any benefit in swapping them at all? I'm not sure how many lanes the Duo has?

Thanks, James.

[Julusian]

So, just to confirm you're sayig this will put Fill and Key down one SDI

It won't do it down one SDI, but in one stream to the card, and then the card will guarantee that they remain in sync.

If so can you confirm which Blackmagic Software to use please? I

Desktop Video Setup is the one. But I believe this is only possible on the Duo2 and Quad2, not any of the older cards. I've never tried doing this on older cards, so someone else need to provide help with configuring that.

would there be any benefit in swapping them at all?

I don't think so. The original Duo only needs a few lanes, I don't know if its 2 or 4, so that 8 lane slot will be plenty.