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• ffmpeg - trying to output timecodes in CSV of segments between blacks

  20 juin 2022, par Soapa Tune

  I would be so glad to have some help with this.

  


  I have video rushes in this form : black > sequence > black > sequence...

  


  I need the start/end timecodes of each sequences (no black) to create segments on another software so I wondering if it's possible with the blackdetect filter of FFmpeg to output only the sequences data in a csv file. No problem with the simple command line to have the blacks but I'm still at this point with unsuccess others test.

  


  The goal is automate this for multiple files by import the csv in a RPA.

  


  Thank you very much.

  


• DVD m2v to mp4, Anamorphic to Square Pixels, 640x480 or 720x540 ?

  10 juillet 2018, par Matt McManis

  I want to use FFmpeg to convert an NTSC DVD .m2v file to an .mp4.

  The original resolution is 720x480 4:3 Anamorphic.

  I want to convert for playback on a computer using a player like VLC, with Square Pixels.

  ---

  To preserve the best quality

  Should I convert stretching the height 720x540 ?

  Or shrink the width 640x480 ?

  Or should I leave it Anamorphic 720x480 ?

  ---

  What is the difference between playing Anamorphic and Square Pixels on a computer monitor ?

  Does the media player always stretch the pixels to display correctly if Anamorphic ?

  Does encoding the height stretch from 480 to 540 by FFmpeg improve anything ?

  ---

  FFmpeg

  ffmpeg
  
  
  
  -framerate ntsc 
  
  
  
  -i input.m2v 
  
  
  
  -c:v libx264 
  
  -preset medium -crf 18 
  
  -pix_fmt yuv420p 
  
  
  
  -s 720x540 
  
  -aspect 4:3 
  
  
  
  -vf "fps=24000/1001" 
  
  
  
  output.mp4

• 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);
  
  }