[Question]: How to only capture the 1/2 monitor by AMFDisplayCapture?

[gang929]

When using AMFDisplayCapture to capture screen with two monitor, can not only capture the first or second monitor, it always capture all monitor together.

xrandr output

xrandr
Screen 0: minimum 320 x 200, current 2624 x 900, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 connected primary 1600x900+0+0 (normal left inverted right x axis y axis) 410mm x 256mm
   1440x900      59.89 +  74.98  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x800      59.81  
   1152x864      75.00  
   1280x720      59.89  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32    56.25  
   640x480       75.00    72.81    66.67    59.94  
   720x400       70.08  
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
HDMI-A-1 connected 1024x768+1600+0 (normal left inverted right x axis y axis) 256mm x 192mm
   1024x768      60.00*+
   1920x1080     60.00    59.94  
   1280x1024     85.02    60.02  
   1440x900      74.98    59.90  
   1280x960      60.00  
   1360x768      60.02  
   1280x800      59.91  
   1280x720      60.00    59.94  
   800x600       60.00  
   720x480       60.00    59.94  
   640x480       60.00  

OS: Ubuntu 22.04.1 5.15.0-46 Display Adapter: AMD RX 470 Amd Driver: amdgpu-install_22.20.50200-1_all.deb

init code

    res = g_AMFFactory.GetFactory()->CreateComponent(m_pContext, AMFDisplayCapture, &m_pDisplayCapture);
    CHECK_AMF_ERROR_RETURN(res, "AMFCreateComponent AMFDisplayCapture failed");
    res = m_pDisplayCapture->SetProperty(AMF_DISPLAYCAPTURE_MONITOR_INDEX, 0);  // or  1
    CHECK_AMF_ERROR_RETURN(res, "Failed to set monitor ID");
    res = m_pDisplayCapture->SetProperty(AMF_DISPLAYCAPTURE_CURRENT_TIME_INTERFACE, m_pCurrentTime);
    CHECK_AMF_ERROR_RETURN(res, "Failed to set current time interface");
    res = m_pDisplayCapture->SetProperty(AMF_DISPLAYCAPTURE_FRAMERATE, AMFConstructRate(30, 1));
    CHECK_AMF_ERROR_RETURN(res, "Failed to set frame rate");
    res = m_pDisplayCapture->SetProperty(AMF_DISPLAYCAPTURE_MODE, AMF_DISPLAYCAPTURE_MODE_KEEP_FRAMERATE);
    CHECK_AMF_ERROR_RETURN(res, "Failed to set CAPTURE_MODE");
    res = m_pDisplayCapture->Init(amf::AMF_SURFACE_UNKNOWN, 0, 0);

    m_pDisplayCapture->GetProperty(AMF_DISPLAYCAPTURE_RESOLUTION, &m_CurrResolution);
    m_pDisplayCapture->GetProperty(AMF_DISPLAYCAPTURE_DESKTOP_RECT, &m_CurrDesktopRect);

    the RESOLUTION always:  2624x900 
    the DESKTOP_RECT always:  2624x900 

How to only capture the first monitor or second monitor, and get the RESOLUTION or DESKTOP_RECT to DisplayPort-1 1600x900

[MikhailAMD]

When the app gets captured surface could you please check values of the surface->GetPlane(0)->GetOffsetX(), GetOffsety(), GetWidth(), GetHeight()?

[gang929]

get the captured surface: width, height

    m_pDisplayCapture->QueryOutput(&data);
    amf::AMFSurfacePtr pSurfPtr(data);
     LOG("capture surface: %d %d %dx%d",
         pSurfPtr->GetPlane(amf::AMF_PLANE_UNKNOWN)->GetOffsetX(),
         pSurfPtr->GetPlane(amf::AMF_PLANE_UNKNOWN)->GetOffsetY(),
         pSurfPtr->GetPlane(amf::AMF_PLANE_UNKNOWN)->GetWidth(),
         pSurfPtr->GetPlane(amf::AMF_PLANE_UNKNOWN)->GetHeight());

    log:  capture surface: 0 0 1600x900

It seams that it only can be get the RESOLUTION by surface property? Have any way to get the captured RESOLUTION after m_pDisplayCapture->Init() and before m_pDisplayCapture->QueryOutput(&data) to call m_pEncoder->Init() ?

[MikhailAMD]

I understand the issue. We will need to fix AMF_DISPLAYCAPTURE_RESOLUTION. It will come with driver update.

[gang929]

so good

[MikhailAMD]

Few things to explain:

• In your setup compositor allocates a single surface for both monitors and AMF applies the correct cropping. In our testing Wayland compositor allocated different surfaces for each monitor.
• AMF Capture component just provides direct access to the compositor surfaces, it doesn't change or copy data.
• If you want to encode the captured surface directly you should know that encoder supports cropping only at right/bottom area. If cropping happens at left/top area you would have to copy surface by surface->Duplicate() function or use AMF color converter which respects all cropping.