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DECKLINK QUAD 2-50fps signal does not work, video blinking

https://forum.blackmagicdesign.com/viewtopic.php?f=4&t=223052

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DECKLINK QUAD 2-50fps signal does not work, video blinking

PostPosted: Tue Jun 10, 2025 2:03 pm
by Krzysztof Sobieranski
Hi.

I had to use a Blackmagic QUAD 2 card with cameras transmitting a 50fps signal. It turns out that the card has a problem with display. On all connectors, the given signal has no synchronization. The image flickers all the time. I checked on the SDI A and B standard, it does not work.

What is the reason for this behavior. I kindly ask for advice.

Installed Sequoia 15.5 system and current 14.5 drivers.
Chris.

Re: DECKLINK QUAD 2-50fps signal does not work, video blinki

PostPosted: Tue Jun 10, 2025 8:41 pm
by Mitra Mahmoodzadeh
Hi Krzysztof,

While 1080p50 may technically operate in SMPTE Level A (~1.5 Gbps), it performs best in SMPTE Level B (~3 Gbps) for optimal bandwidth and stability. Some broadcast cameras allow manual selection between Level A and Level B in their SDI output settings—check your camera’s menu for this option.

Use a high-quality 3G-SDI cable—low-quality or long cables may handle 1080p25 but fail at 1080p50.

Test signal capture using Blackmagic Media Express.