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• Show motion compensated images in ffmpeg

  29 novembre 2017, par igon

  This guide shows how to visualize with FFmpeg interesting features (quantization parameters, motion vectors, ...) of an encoded video. One things that I find missing is a way to show motion compensated frames and/or residual frames.

  Is this information exposed by encoders ? Is there a way to visualize it ?

• capture attribute to show the camera directly

  29 août 2017, par PKnight

  Dialog Box

  I would expect specifying the capture attribute to show the camera directly, rather than having to navigate through the dialog boxes above.
  I want the camera to go directly and I can record a video.

  <input type="file" accept="video/mp4,video/x-m4v,video/*" capture="camcorder" />

  I tried in several ways, but none worked. It’s always shows the dialog box to choose a camera. Can anybody help me ? Thank you

• FFMPEG + SDL : How To Show Multi Frames In Separate Region ?

  19 mai 2014, par user3051473

  I’m using ffmpeg and SDL to develop an camera monitor APP and I want to show four separate streams at the same time(via four rtsp source). As following figure out :

  Now I achieve this by setting the SDL display region, and I identify different display region by using the different SDL_Rect identifying by the variable i(from 1 - 4).

  But this cause the efficient problem. For every region, I need to scale to the whole screen and lock/unlock screen, then display.

  I’m wondering that, Can I merge 4 different AVFrame(come from REG1 - REG4) into the whole picture and then show this picture ?

  Hope that the describe about is detail enough for you to konw my problem.
  Also thanks for your help.

  -------------------
  
  -        -        -
  
  -  REG1  -  REG2  -
  
  -        -        -
  
  -------------------
  
  -        -        -
  
  -  REG3  -  REG4  -
  
  -        -        -
  
  -------------------
  
  
  
  public void ShowFrame(AVFrame *pFrame, AVCodecContext *pCodecContext)
  
  {
  
      SDL_LockYUVOverlay(pBmp);
  
      AVPicture pict;
  
  
  
      // TODO scale pFrame to pict
  
      // ...
  
  
  
      SDL_UnlockYUVOverlay(pBmp);
  
  
  
      // WIDTH and HEIGHT represent the whole screen size
  
      SDL_Rect rect;
  
      rect.x = (WIDTH / 2) * (i % 2);
  
      rect.y = (HEIGHT / 2) * (i > 1 ? 1: 0);
  
      rect.w = WIDTH / 2;
  
      rect.h = HEIGHT / 2;
  
      SDL_DisplayYUVOverlay(pBmp, &rect);
  
  }