What is the best device to capture an HDMI video stream?


#1

Hi,
I am currently working at a project where I have to draw stuff over a live video feed coming from a TV set via HDMI (at 1920x1080). Of course this will need a separate piece of hardware to be connected, and an advice about it would be very welcome.

Has anybody already tried something like this (I suppose so) and is willing to help?

So far I tried the Avermedia Live Gamer Portable, but couldn’t manage to make it work properly. It needs a separate software to decode its proprietary protocol and present it as a webcam, and for some reason only the first frame after connecting the HDMI cable can be read from ofVideoGrabber.

Peeking among the extensions I found a few for the Blackmagic series, can somebody give me a hint about which is the cheapest device capable to do the job? The system should be installed in public places (like bars and clubs) so it would be better to avoid expensive and sophisticated hardware if possible.

Unfortunately I am working on a tight budget (out of my own money) and cannot afford to buy several devices to choose among them.

Thanks for helping and all the best,
Davide


#2

I need to do something similar (using hdmi output of a camcorder) and i’m also curious about recommend hardware which works well with OF.


#3

I have had good luck with this one

https://www.bhphotovideo.com/c/product/892453-REG/Blackmagic_Design_bdlkulsdzminrec_Ultrastudio_Mini_Recorder.html

I used ofxBlackmagic2 to capture https://github.com/elliotwoods/ofxBlackmagic2.

also, if it’s helpful, I’ve found the usb-3 black magic devices to be slightly spotty in terms of starting properly… once they are up they are very stable, but I find I have to unplug and plug in the device more often then I would like. The thunderbolt devices are really solid.


#4

Very interesting, the Mini Recorder is also quite cheap. Too bad thunderbolt is not standard on most PC… I develop on macs but the software will have to be used on both OSX and Windows.

The reviews for USB capture devices are not so good, as you said, but for the sake of compatibility I’ll give them a try too.

@zach with the Mini Recorder can you grab a full HD HDMI stream and show it onscreen in real time? What about the audio?

Thanks
Davide


#5

with both you can (I think they max out at 1080p 30hz, IIRC)-- not sure about audio as I haven’t tested that. the usb one was fine it just was hit or miss on startup and I really dislike that in a device. One it was up it will run for hours fine.


#6

I just borrowed a Magewell capture card from a friend: http://www.magewell.com/usb-capture-hdmi/tech-specs
With 300$ it’s not exactly cheap but it works really great - and it’s class compliant! Plugged it into my Lenovo Thinkpad (Windows 7) and after 3 seconds it was ready to capture :-).


#7

@Christof thanks for this recommendation. Do you pull this feed into oF as a webcam, using ofVideoGrabber?


#8

yes! it shows up in the list of video grabber devices.


#9

Thanks for the recommendation! I’m working on a similar project here!
I got a BM mini recorder and downloaded the ofxBlackmagic2, but when I ran the example, or just included the addon in a new project, it didn’t complied, showing “‘rpc.h’ file not found” (in the DeckLinkAPI_i.c file)
Also tried the other alternatives on GitHub, didn’t work either.
Not sure whether it is because it’s running on Mac rather than PC? Do you have any idea about this issue?

And I’m actually thinking to use openCV to do computer vision animation base on the live-streamed video. Is there member named like ‘getPixels’ in ofxBlackmagic2?

Thanks so much!
Bing

the screenshot: