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• How can I CORS enable with callback function using golang ? [closed]

  24 juin 2021, par mr jony

  How can I CORS enable remote server that means video streaming from remote server or IP address ? I want to CORS enable using callback function using GOLANG.

  


• Intel IPP RGBToYUV420 function is getting IppStsSizeErr result code

  6 février 2018, par yesilcimen.ahmet

  I am using IPP 2017.0.3(r55431) and Delphi 10.2, I am trying convert RGB to YUV420P, but I am getting IppStsSizeErr result code.

  I have m_dst_picture, m_src_picture: AVPicture structure created by FFMPEG.

  { allocate the encoded raw picture }
  
  
  
   ret := avpicture_alloc(@m_dst_picture, AV_PIX_FMT_YUV420P, c^.width, c^.height);
  
  
  
   if (ret < 0) then
  
      Exit(False);
  
  
  
   { allocate BGR frame that we can pass to the YUV frame }
  
   ret := avpicture_alloc(@m_src_picture, AV_PIX_FMT_BGR24, c^.width, c^.height);
  
   if (ret < 0) then
  
     Exit(False);
  
   //It works fine.
  
   { convert BGR frame (m_src_picture) to and YUV frame (m_dst_picture) }
  
   sws_scale(sws_ctx, @m_src_picture.data[0], @m_src_picture.linesize, 0, c^.height, @m_dst_picture.data[0], @m_dst_picture.linesize);

  I want to convert the RGB buffer directly to YUV420P. The original code first loads RGB into the AVPicture then convert RGB to YUV420P with sws_scale and it causes slowness.

  Here I copy the BGR buffer to m_src_picture of FFMPEG. But this leads to performance loss, so I want to convert it directly to YUV420P using Intel IPP.

  procedure WriteFrameBGR24(frame: PByte);
  
  var
  
    y: Integer;
  
  begin
  
    for y := 0 to m_c^.height - 1 do
  
      Move(PByte(frame - (y * dstStep))^, PByte(m_src_picture.data[0] + (y * m_src_picture.linesize[0]))^, dstStep);
  
  end;

  In the code below I am trying to convert using Intel IPP.

  { Converting RGB to YUV420P. }
  
  
  
  **roiSize is 1920 and 1080
  
  
  
  **The values created by FFMPEG for YUV420P in m_dst_picture.linesize are [0]=1920,[1]=960,[2]=960 respectively.

  Do I need to convert the values of the linesize to another value ?

  **The reason why the srcStep parameter is a minus sign is the Bottom-Up Bitmap and the frame pointer indicates the Bmp.ScanLine[0] address, which indicates the highest pointer address.

  srcStep := (((width * (3 * 8)) + 31) and not 31) div 8; //for 24 bitmap
  
  
  
  { Swap of BGR channels to RGB. }
  
  //It works fine    
  
  st := ippiSwapChannels_8u_C3IR(frame, -srcStep, roiSize, @BGRToRGBArray[0]); 
  
  
  
  { Convert RGB to YUV420P. }
  
  //IppStsSizeErr  
  
  st := ippiRGBToYUV420_8u_C3P3R(frame, -srcStep, @m_dst_picture.data[0], @m_dst_picture.linesize[0], roiSize);

  How do I solve this problem ?

  Thank you.

• flutter : record a video that has same duration as animated webp

  2 mai 2020, par Chris

  what I'd like to do :
I would like to record a video using Flutter's CameraController that has the same duration as an animated webp. On top of my screen, the animated webp is playing and below there is a CameraPreview() widget that records whatever my camera catches. This recorded video's duration should be exact as long as the animated webp's duration.

  



  what I've tried so far :
Since Giphy offers not only a webp-version, but also an mp4-version, I downloaded the mp4 version and used ffmpeg to get the duration of that file. 
I then used a timer and called VideoController.stopVideoRecording() after this duration automatically after VideoController.startVideoRecording().

  



  what I'd expect to happen :
I'd expect this recorded video to be as long as the animated webp. Unfortunately, it's not.

  



  So, my question is :
Do you guys have any idea how I could manage to record a video with same duration as an animated webp ?

  



  Thanks :)