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• SDL2 C++ Capturing Video of Renderer Animation/Sprite

  27 octobre 2016, par alok

  I have an animation/sprite created using SDL2. The animation works fine when it is being rendered to a screen. But now I also want it to be recorded into a video file (locally stored). For this, I am planning on using FFmpeg APIs, to which I’ll be sending a raw RGB pixel data array.

  My problem is with fetching the data from SDL2 APIs.

  What I’ve tried is :

  // From http://stackoverflow.com/questions/30157164/sdl-saving-window-as-bmp
  
  SDL_Surface *sshot = SDL_CreateRGBSurface(0, 750, 750, 32, 0x00ff0000, 0x0000ff00, 0x000000ff, 0xff000000);
  
  SDL_RenderReadPixels(gRenderer, NULL, SDL_PIXELFORMAT_ARGB8888, sshot->pixels, sshot->pitch);
  
  
  
  // From https://wiki.libsdl.org/SDL_RWFromMem
  
  char fName[50];
  
  sprintf(fName, "/tmp/a/ss%03d.bmp", fileCnt);
  
  
  
  
  
  char bitmap[310000];
  
  SDL_RWops *rw = SDL_RWFromMem(bitmap, sizeof(bitmap));
  
  SDL_SaveBMP_RW(sshot, rw, 1); 

  Above does not work. But dumping a single frame into a file with following code works :

  SDL_SaveBMP(sshot, "/tmp/alok1/ss.bmp")

  This obviously is not an acceptable solution - Writing to thousands of BMPs and then using FFmpeg from command-line to create a video.

  What am I doing wrong ? How do you extract data from SDL_RWops ? Is the use of SDL_RWFromMem the right approach to my problem statement ?

• ffmpeg for archval and convertability

  26 juillet 2021, par Satya

  I've got a couple hundred gigs of *.dv files. I'd like to convert them to H.264 or something else or even leave them alone. The purpose is archival, with an eye to maximum convertability especially to DVD. The content is family videos.

  


  Would this be fine ?

  


  ffmpeg -i input.dv \
    -c:v libx264 -preset slower \
    -crf 17 \
    -pix_fmt yuv420p \
    output.mp4


  


  I went with the slower preset because encoding time isn't an issue and I'd like a smaller file size. crf 17 is for least-lossy while being widely playable. I read somewhere that yuv420p is needed for some Quicktime players.

  


  Should I throw in -c:a aac for AAC audio ? The audio is voice only, no need for music-hall quality.

  


  I looked at https://trac.ffmpeg.org/wiki/Encode/H.264 for previous research and that's where I got those settings, but it is silent on the audio settings.

  


• instalation ffmpeg in Ubuntu [migrated]

  27 août 2014, par Chintan Gor

  I am using following steps for installing ffmpeg-php extension in Ubuntu

  1. Download ffmpeg-php-0.5.2.1.tbz2

  2. extract it

  3. go to this directory

  4. run this "phpize"

  5. ./configure && make

  but when I am running step 5 I got this error message "ffmpeg shared libraries not found. Make sure ffmpeg is compiled as shared libraries using the —enable-shared option
  "

  what to do please someone help me I am fresher in Linux

  I already install ffmpeg in this machin using this steps
  https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

  Now I am installing extension for PHP

  using this steps from this http://ffmpeg-php.sourceforge.net/

  INSTALLATION