Nvidia Turing cards do not support interlaced video decoding

Hi Caspar Forum!

I’ve been told by one of our engineers that they’ve had problems in a gallery with a newer PC running a newer Nvidia graphics card and interlaced video. Upon some research they’ve found that Nvidia Turing cards do not support interlaced video decoding.

Has anyone experienced problems with this and is the best option to stick with a Quadro card (I assume the newer Quadro models do support interlaced?).


CCG doesn’t do any video decoding on Nvidia cards - unless that change has gone unnoticed by me.

IIRC the interlace limitation is for h264 encoding only - on Turing. Pascal and earlier all support interlaced encoding.

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Thank you @hreinnbeck thats really useful info.

I can see this being an issue when using the screen consumer and running the output from the graphics card straight into an ATEM.
The only work around I can think of is to use an UpDownCross (or similar) converter.

To keep thing simple better you plug a decklink card.
Output directly from decklink instead of outputting from graphics card and then UDC.
No headaches, cheaper in terms of price, more reliable and far less destructive on picture quality since you output native resolution not something else which is later re-scaled.

Hi All
Checking with the engineers @Jon 's scenario is in fact the case.
What we actually have is a scenario where the decklink output key and fill is used for one channel then the HDMI from graphics card is used for a screen consumer for a second channel.

Traditionally this has worked fine, but the lack of interlaced option on the new graphics card has caused problems.

Plug an extra decklink mini monitor and the problem is solved.

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That’s why I always recommend the use of the Decklink Duo 2, also if they tell you they need only one fill & key. It has 4 BNC’s that can be in- or output and so you always get that extra preview channel or an input for anything like ScorebordOCR etc.

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Thats a great idea, thanks @didikunz

I wish it were that simple haha!
We have a number of machines that, when running Caspar, use a decklink extreme for key and fill and the windows extended desktop (graphics card output) for the screen consumer (running in 1080i50). These machines are also used to run other software such as powerpoint and other task-specific playout software that all run on the extended desktop and require the graphics card to output in interlaced.
A pain but it’s just something we will need to bear in mind when getting new machines!

An idea could be to use the NDI screen grabber to send the extended desktop, running progresive, to a Caspar channel running interlaced on a Decklink.