Blackmagic Forum

What is going on? I would like to record progressive video, not interlaced video. But when I set my camera to progressive signal, the card sees it as interlaced SDI signal.

I updated the DeckLink Mini Recorder driver-software (Desktop Video Setup) to the latest version 11.7 and noticed that the camera's (JVC GY-HM750U) SDI signal is wrongly interpreted.

I have the camera set to 1080p25 and the driver displays a SDI video input of 1080i50. Why is it not displaying 1080p25?

This is what it looks like when setting the camera to 1080p25:



I can change the camera to 1080i50 and it remains displaying a 1080i50 signal; however, when setting the camera to 1080p30, I get the same unexpected signal of 1080i59.94 and not 1080p30. Setting the camera to 1080i60 I get the expected 1080i59.94 read. But to confuse matters even further, setting the camera to 1080p24 -- I get 1080i59.94.

These are my camera Record Format options:



Setting the camera set to 1080p25, and using BlackMagic Media Express, it automatically starts a project with these presets of 1080i50 Rec.709; and I have video that I can record and see:



I can record video at this preset setting, and when checking the video, it is interlaced but I want it to be progressive.



Link to full report (.txt file)


Now changing Preference to 1080p25



... and to any of the suggested Capture File Formats, it turns the signal in the bottom right corner red, and I do not see any video, nor can I record any.



Help - thanks!

The JVC is a legacy eng camera. It will output a 1080i SDI signal regardless of camera shooting format. I have a JVC HD101E that does the same with component to SDI conversion and BR-HD50E deck that does so over HDMI too. Similarly, 24p will be over 1080i60 a la Varicam. On the deck capturing to Avid via Ultrastudio Mini 4K, I have to set it to native to avoid clear interlacing artifacts with progressive SD/HD formats. So long as you're not seeing these artifacts you should be able to capture 25p to 1080p25 codecs without issue even if the Decklink shows the signal as 1080i50.

Steve Fishwick:

... you should be able to capture 25p to 1080p25 codecs without issue even if the Decklink shows the signal as 1080i50.

That's false. Maybe your software will do that internally, but not for me.

If DeckLink indicates 1080i50 then BlackMagic Media Express (or Edius, which is what I use to record) will only record interlaced video, not progressive video.

It seems that DeckLink is only able to provide an interlaced signal to record from, even with a progressive signal, as explained above:

... it turns the signal in the bottom right corner red, and I do not see any video, nor can I record any.

Sure, I can easily convert interlaced video to progressive video at a later point (and maybe I'm splitting hairs a bit here with this post), but based on the DeckLink Mini Recorder Tech Specs one would think that it should also provide recording capabilities of a 1080p signal to 1080p file.

I vaguely remember way back when I got the card, that I was able to set it up to record progressive -- but I may be mistaken.

I know that over the many years BM has had many driver updates - so has Edius. Both were trying to get a cleaner video lock to the signal; and their effort shows some real improvement! I used to have to turn the camera Off and On again, up to 20 times, to finally have a read on the signal. Now DeckLink finds it instantly. (Thank you for that!)

Go fish, this camcorder does not support 1080P over SDI.

Good Luck

Thank you Howard Roll. That would explain my problem!

Howard Roll wrote:Go fish, this camcorder does not support 1080P over SDI.

Hey Howard how did you know people call me Fish?

Nat, I don't use Eidus nor Media Express, I use Avid for legacy capture and I can capture a 1080i50 signal into a 1080p25 project with the Ultrastudio with no problems, so it's not false insofar as it's possible, perhaps not with every capture software and it's definitely possible to capture 1080p with a Decklink/Ultrastudio - 1080p25 over 1080i50 SDi is 1080psf, segmented frame - the Ultrastudio will output that too. As Howard confirmed that camera spits only 1080i, whatever the shooting format, so if the software can't crossconvert on the fly you're stuck with that codec. If you need 1080p record to SD and import.

Good luck and all the best for 2021 guys.