Bmdcapture and Bmdplay on the same card at the same time

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Fernando Cavero

  • Posts: 2
  • Joined: Wed Dec 13, 2017 11:00 am

Bmdcapture and Bmdplay on the same card at the same time

PostWed Dec 13, 2017 11:37 am

Hello Everybody,


I´m developing a python program with opencv (on Ubuntu system) which capture video then process the video and draw on it and then it show this processed video on my vga monitor.

I have a decklink sdi card.

For the capture I´m using this command:

Code: Select all
./bmdcapture -m 1 -A 2 -V 4 -F nut -f  pipe:1|ffmpeg -i - -q 5 -r 25 -s 1024x576 -f mpeg1video udp://localhost:5010


Then on my python code i work with the udp://localhost:5010 stream and finish my program with:

Code: Select all
        ....
        cv2.imshow('Video Stream', frame)#Show the video stream on my Vga
        sys.stdout.write( frame.tostring() ) #write the raw video frames to stdout to pipe to Bmdplay


To run my program i write the next command:

Code: Select all
python DrawOnVideo.py | avconv -f rawvideo -pixel_format uyvy422 -video_size 720x576 -framerate 25 -an  -i - -f nut -f_strict experimental -syncpoints none - | ./bmdplay -m 1 -f pipe:0 -O 4 


Now i can see on my terminal the output of Bmdplay running without errors, also i can see the video signal processed on my VGA monitor, but blackmagic card all the time is playing the input signal and i want it play the video which is output from my python program.

Can someone help me with this?

There is some method wich the bmdcapture leave free the output of the card?, because i think my problem is that bmdcapture appropriate the output connector.

I hope someone can help me with this.

Thank you very much.
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Xtreemtec

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  • Location: The Netherlands

Re: Bmdcapture and Bmdplay on the same card at the same time

PostWed Dec 13, 2017 8:29 pm

I wonder if that was possible with the early cards to do capture and playback at the same time..

I heard some people about the new cards being capable of that.. And Also the new duo and quad cards will do this for sure.. But the Decklink Sdi is a much older card.. 4+ years if i guess correctly..
Daniel Wittenaar .:: Xtreemtec Media Productions ::. -= www.xtreemtec.nl =-
4K OBV, ATEM TVS HD, 1M/E 4K, 2M/E Broadcast Studio 4K, Hyperdeck Studio Mini, SONY FS7 4K, Ursa Broadcast 4K
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Dave Johnstone

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  • Location: Adelaide

Re: Bmdcapture and Bmdplay on the same card at the same time

PostWed Dec 13, 2017 10:49 pm

Xtreemtec is correct, the non-4k cards are not full duplex (see thread viewtopic.php?f=12&t=34835&p=307541). These older cards can key graphics over the input video, if that's all you need. The Decklink SDI can only key in SD mode.

Regards,

Dave.
Freelance Television Broadcast Engineer
and Software Programmer.
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Fernando Cavero

  • Posts: 2
  • Joined: Wed Dec 13, 2017 11:00 am

Re: Bmdcapture and Bmdplay on the same card at the same time

PostMon Dec 18, 2017 8:20 pm

Thank you very much, i will try to probe with a new Duo card if is posible to do it, i will tell you here.

Thank you very much for your great support.

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