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• FFmpeg : Encode x264 with AMD GPU on Windows ?

  20 septembre 2023, par ZeroTek

  I am currently trying to record a Video on my Lenovo Laptop with its Built-In Webcam using FFmpeg on Windows 10. One of my goals is to keep the CPU Usage as low as possible, that's why i want to push the h264 encoding to the GPU. 
Now it gets a bit tricky here with my Laptop. Because it uses two GPUs. The first GPU is a Intel HD 5500 Graphics Unit as Part of the CPU. This one is most likly used for non-demanding Applications like office etc. to save Energy. The other one is a AMD R5 M330 that will be used for graphic intense applications like gaming.

  



  Currently, i am using the following command to encode the Webcam Stream on the Intel HD GPU :

  



  ffmpeg -f dshow -vcodec mjpeg -video_size 1280x720 -framerate 30 video="Lenovo EasyCamera":audio="Mikrofon (Realtek High Definition Audio)" -c:v h264_qsv -g 60 -q 28 -look_ahead 0 -preset:v faster -c:a aac -q:a 0.6 -r 30 output.mp4


  



  This does work so far but it seems this GPU does not have enough Power to keep up with the framerate on higher bitrates or with a high amount of i-frames. The Video starts lacking and skipping frames. If i am using CPU encoding everything works smooth.

  



  Now that my Laptop got that second AMD GPU with a lot more Power it would be a nice Try to encode on that one, but i can't find any information about how to encode on AMD Hardware on Windows 10. So my question is : How does the ffmpeg command look like to use AMD Hardware for h264 encoding ?

  


• How can I use avformat_open_input function (ffmpeg)

  5 mai 2016, par johncarrie

  I have bought a HD HDMI to UVC device which has HDMI video source input and UVC for video output here.
  I connect it from laptop A (input source HDMI) to laptop B (output USB).
  I have installed Ubuntu 14.04 desktop on Laptop B and Win 8.1 on Laptop A.
  B also have ffmpeg, opencv and sdl library installed.
  My target is to capture video and audio from A via HD HDMI to UVC on B.
  So I have decided to use libav of ffmpeg.
  I saw this and used avformat_open_input function but this function returned error.
  I thought that the error was occurred because the second parameter of avformat_open_input (const char * url) was invalid.
  I know that the url should be like video:video device name:audio:audio card name.
  How can I indicate the device names ?

  Here’s the result of v4l2-ctl --list-devices command in terminal.

  HD WebCam (usb-0000:02:03.0-1):   
  
      /dev/video0
  
  HD TV CAM (usb-0000:03:00.0-2.1):   
  
      /dev/video1

  And the result of arecord -l in terminal.

  **** List of CAPTURE Hardware Devices ****  
  
  card 0: AudioPCI [Ensoniq AudioPCI], device 0: ES1371/1 [ES1371 DAC2/ADC]  
  
  Subdevices: 1/1  
  
  Subdevice #0: subdevice #0    
  
  card 1: CAM [HD TV CAM], device 0: USB Audio [USB Audio]    
  
  Subdevices: 1/1  
  
  Subdevice #0: subdevice #0  

  Thank you.

• Get RGB values from AVPicture and change to grey-scale in FFMPEG

  22 octobre 2014, par user2742299

  The main motive of my code is to change the RGB values from the AVPicture in FFMPEG.

  I have been able to get the image data "data[0]" by following the article : http://blog.tomaka17.com/2012/03/libavcodeclibavformat-tutorial/

  I would like to know that how can I access the 3 bytes of pic.data[0] which is in RGB format. I have been trying to access the pic.data[i][j] via for-loop in 2D matrix fashion but jth element>3.

  Any guidance in this regard will be helpful.

  Code is here :

  AVPicture pic;
  
          avpicture_alloc(&pic, PIX_FMT_RGB24, mpAVFrameInput->width,mpAVFrameInput->height);
  
          auto ctxt = sws_getContext(mpAVFrameInput->width,mpAVFrameInput->height,static_cast<pixelformat>(mpAVFrameInput->format),
  
              mpAVFrameInput->width, mpAVFrameInput->height, PIX_FMT_RGB24, SWS_BILINEAR, nullptr, nullptr, nullptr);
  
  
  
          if (ctxt == nullptr)
  
              throw std::runtime_error("Error while calling sws_getContext");
  
          sws_scale(ctxt, mpAVFrameInput->data, mpAVFrameInput->linesize, 0, mpAVFrameInput->height, pic.data,
  
              pic.linesize);
  
  
  
  
  
      for (int i = 0; i &lt; (mpAVFrameInput->height-1); i++) {
  
  
  
          for (int j = 0;  j &lt; (mpAVFrameInput->width-1); j++) {
  
          printf("\n value: %d",pic.data[0][j]);
  
  
  
          }
  
  
  
      }
  
  </pixelformat>

  Pseudo code which is in my mind is :

  For each pixel in image {
  
  Red = pic.data[i][j].pixel.RED;
  
  Green = pic.data[i][j].pixel.GREEN;
  
  Blue = pic.data[i][j].pixel.BLUE;
  
  GRAY = (Red+Green+Blue)/3;
  
  Red = GRAY;
  
  Green = GRAY;
  
  Blue = GRAY;
  
  Save Frame;}

  I am quite new to FFMPEG therefore any guidance and help will be highly appreciable.

  Many Thanks