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• How do I create and initialise a DXGI_FORMAT_NV12 resource in DX12 (source is AVFrame)

  5 janvier 2023, par mike

  I'm trying to create an NV12 resource as source for a video encoder in DX12. While I intend to eventually populate a resource from GPU, what I'm trying to do now is take an ffmpeg AVFrame I already have (in AV_PIX_FMT_YUV420P format) and create a texture in DXGI_FORMAT_NV12 format using that data.
  

  


  I understand the NV12 format (https://learn.microsoft.com/en-us/windows/win32/medfound/recommended-8-bit-yuv-formats-for-video-rendering#nv12) has U and V interleaved while the AV_PIX_FMT_YUV420P doesn't.

  


  My main question is what does the D3D12_RESOURCE_DESC look like for an NV12 texture - do I tell it I need more than one array/mip level to make it planar ? Or do I just give it a single memory address with both planes layed out as per the NV12 format, and it figures out subresources for me based on the format ?
  
I understand that to read the data I define two SRVs, one for Y mapped to the Red channel and a second for U and V, but it's how I initialise it that's confusing me.

  


• Encode and stream from Xbox 360 kinect using ffmpeg

  17 juin 2015, par user3288346

  I want to live stream content obtained from Kinect onto my internal network.

  I have one physical machine which is my server and has ubuntu 14.04 Server on it. I connect remotely to it. I have installed ffmpeg and ffserver and can encode and stream stored video files on the server. However, I have a few problems when using the Xbox Kinect.

  I have xbox 360 kinect which I have attached through usb. I have followed this https://bitbucket.org/samirmenon/scl-manips-v2/wiki/vision/kinect, however I couldn’t get through the OpenCV part. When I run

  $ cmake-gui ..

  I get

  cmake-gui: cannot connect to X server 

  I don’t have physical access to the machine. Probably, its due to accessing it remotely.

  When I do

  test@cloud-node-2:~/kinnect$ lsusb
  
  Bus 002 Device 006: ID 045e:02ae Microsoft Corp. Xbox NUI Camera
  
  Bus 002 Device 004: ID 045e:02b0 Microsoft Corp. Xbox NUI Motor
  
  Bus 002 Device 005: ID 045e:02ad Microsoft Corp. Xbox NUI Audio
  
  Bus 002 Device 003: ID 0409:005a NEC Corp. HighSpeed Hub
  
  Bus 002 Device 002: ID 0bda:0181 Realtek Semiconductor Corp. 
  
  Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  
  Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  
  Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  
  Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub 

  When I do

  test@cloud-node-2:~/kinnect$ ls -ltrh /dev/video*
  
  ls: cannot access /dev/video*: No such file or directory

  Therefore, I am not able to capture the video using ffmpeg.

• How to create a video out of frames without saving it to disk using python ?

  6 septembre 2022, par brenodacosta

  I have a function that returns a frame as result. I wanted to know how to make a video out of a for-loop with this function without saving every frame and then creating the video.

  


  What I have from now is something similar to :

  


  import cv2
out = cv2.VideoWriter('video.mp4',cv2.VideoWriter_fourcc(*'DIVX'), 14.25,(500,258))
for frame in frames:
    img_result = MyImageTreatmentFunction(frame) # returns a numpy array image
    out.write(img_result)
out.release()


  


  Then the video will be created as video.mp4 and I can access it on memory. I'm asking myself if there's a way to have this video in a variable that I can easily convert to bytes later. My purpose for that is to send the video via HTTP post.

  


  I've looked on ffmpeg-python and opencv but I didn't find anything that applies to my case.