main.cpp

[github-jeff]

OS: Ubuntu 20.04

I have adjusted the make file to reference both the opencv4/opencv2 directory as well as the black magic SDK directory.

Makefile:

xx = g++
OPEN_CV = 3rd_party/opencv4
BMD_SDK = 3rd_party/blackmagic_decklink_sdk/Linux/include
INC = $(OPEN_CV) $(BMD_SDK)
INC_PARAMS = $(foreach d, $(INC), -I $d)
source = *.cpp $(BMD_SDK)/DeckLinkAPIDispatch.cpp
prom = decklink_opencv
libs = -lopencv_core -lopencv_highgui -lopencv_imgproc -lpthread -lstdc++ -ldl -lDeckLinkAPI
decklink_opencv: $(source)
	$(xx) -o $(prom) -Wall -std=c++11 $(source) $(INC_PARAMS) -L /usr/local/lib $(libs) -O3

The only modification that I have made to your code, beyond the Makefile is in DeckLinkUtil.hpp in line 8 was

#include <opencv2/highgui.hpp>
#include <opencv2/highgui.h>

$make yields the following error.

DeckLinkUtil.cpp: In member function ‘int DeckLinkUtil::startCaptureWithDisplayMode(int)’:
DeckLinkUtil.cpp:91:26: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<IDeckLinkDisplayMode*>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   91 |     if (mode < 0 || mode >= displayModeList.size()) {
      |                     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
main.cpp: In function ‘int main(int, const char**)’:
main.cpp:17:43: error: no matching function for call to ‘DeckLinkUtil::DeckLinkUtil()’
   17 |     DeckLinkUtil *util = new DeckLinkUtil();
      |                                           ^
In file included from main.cpp:12:
DeckLinkUtil.hpp:28:5: note: candidate: ‘DeckLinkUtil::DeckLinkUtil(int)’
   28 |     DeckLinkUtil(int id);
      |     ^~~~~~~~~~~~
DeckLinkUtil.hpp:28:5: note:   candidate expects 1 argument, 0 provided
make: *** [Makefile:10: decklink_opencv] Error 1

When I picked a value: (0) was used for the initial commit, so I put it back in.

DeckLinkUtil *util = new DeckLinkUtil();
DeckLinkUtil *util = new DeckLinkUtil(0);

The code compiles but alas there is no display. Just a black screen. All modes were tried 0 - 20 including x. OBS works so there is certainly data to be displayed.

[js-john]

Is your input signal HDMI or SDI? The default signal input of the BMD capture card is SDI. If you use HDMI, try to select "HDMI" as the input signal source in Blackmagic Desktop Video Setup app.

[github-jeff]

It is set to HDMI, and works in OBS Studio in mode 1080@60.

…

On Sun, Nov 15, 2020, 9:08 PM js_john ***@***.***> wrote: Is your input signal HDMI or SDI? The default signal input of the BMD capture card is SDI. If you use HDMI, try to select "HDMI" as the input signal source in Blackmagic Desktop Video Setup app. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#2 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AE5LSJB4RDMH2HZXIXMRBELSQCCTHANCNFSM4TWQ3KQQ> .

[js-john]

It seems that your capture card supports 1080@60 (1080P or 1080i ?). I have Ultrastudio Mini Recorder and DeckLink Mini Recorder and the bandwidth can only support to 1080P@30 or 1080i@60. May be I have to make some changes to make it compatible to your device.

[github-jeff]

Thanks for taking a look. I will gladly test the new revision when it becomes available. The card I am using is Intensity Pro 4K.

These are the current input settings and card type which currently work.

The mode list when running your code reports special characters instead of listing the modes. Yes, you can look them up but since you are into the code, you might as well know.

Since you are looking at the code, and not sure it really matters, or if it was intentional, but the DectlinkOpencv folder is miss-spelled. I made the mistake a few times when trying to call it.

[js-john]

@github-jeff
I found a official sample code here: https://www.blackmagicdesign.com/developer/product/capture-and-playback
here is the demo code processing with opencv
https://downloads.blackmagicdesign.com/Developer/DesktopVideo/20191007-3b38c1/Blackmagic_Desktop_Video_Developer_Live_Video_Processing_with_OpenCV_1.0.zip

[js-john]

@github-jeff by the way.. I use std::cout instead of printf but i don't have linux machine right now to check if the display mode list bug is fixed.

[github-jeff]

I swapped out the Makefile with the one listed above. Brought in the 3rd party files opencv4, and blackmagic sdk. The code compiled with only one warning:

DeckLinkUtil.cpp: In member function ‘int DeckLinkUtil::startCaptureWithDisplayMode(int)’:
DeckLinkUtil.cpp:91:26: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<IDeckLinkDisplayMode*>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   91 |     if (mode < 0 || mode >= displayModeList.size()) {
      |                     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

The mode display did change, but it's not readable.

Here is a pretty good explanation of what is happening in Linux consoles and what can be done code wise. There are a few options for your consideration.

https://stackoverflow.com/questions/13809611/cout-and-cin-in-linux-cant-see-the-console

When the code is run, the monitor window does open but it unfortunately does not display the video source. I will see if the BMD demo sheds any light as to what is happening here. In the meantime, if you want to work on this, please let me know and i will happily test as many revisions as you like.