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• Video too fast FFmpeg

  22 novembre 2012, par Spamdark

  I am having an issue again with ffmpeg, I'm a newbie with ffmpeg, and I can't find a good tutorial up to date...

  This time, when I play a video with ffmpeg, it plays too fast, ffmpeg is ignoring the FPS, I don't want to handle that with a thread sleep, because the videos have differents FPS's.

  I created a thread, there you can find the loop :

  AVPacket framepacket;
  
  
  
  while(av_read_frame(formatContext,&framepacket)>= 0){
  
      pausecontrol.lock();
  
  
  
      // Is it a video or audio frame¿?
  
      if(framepacket.stream_index==gotVideoCodec){
  
          int framereaded;
  
          // Video? Ok
  
          avcodec_decode_video2(videoCodecContext,videoFrame,&framereaded,&framepacket);
  
          // Yeah, did we get it?
  
          if(framereaded && doit){
  
              AVRational millisecondbase = {1,1000};
  
              int f_number = framepacket.dts;
  
              int f_time = av_rescale_q(framepacket.dts,formatContext->streams[gotVideoCodec]->time_base,millisecondbase);
  
              currentTime=f_time;
  
              currentFrameNumber=f_number;
  
  
  
              int stWidth = videoCodecContext->width;
  
              int stHeight = videoCodecContext->height;
  
              SwsContext *ctx = sws_getContext(stWidth, stHeight, videoCodecContext->pix_fmt, stWidth,
  
              stHeight, PIX_FMT_RGB24, SWS_BICUBIC, NULL, NULL, NULL);
  
              if(ctx!=0){
  
              sws_scale(ctx,videoFrame->data,videoFrame->linesize,0,videoCodecContext->height,videoFrameRGB->data,videoFrameRGB->linesize);
  
              QImage framecapsule=QImage(stWidth,stHeight,QImage::Format_RGB888);
  
  
  
              for(int y=0;ydata[0]+y*videoFrameRGB->linesize[0],stWidth*3);
  
              }
  
              emit newFrameReady(framecapsule);
  
              sws_freeContext(ctx);
  
              }
  
  
  
          }
  
      }
  
      if(framepacket.stream_index==gotAudioCodec){
  
          // Audio? Ok
  
      }
  
      pausecontrol.unlock();
  
      av_free_packet(&framepacket);
  
  }

  Any Idea ?

• ffmpeg - converting pngs with white background to movie give black background

  14 octobre 2015, par Population Xplosive

  I have a list of files with their names in the form [1-1000].00.png.
  All these are flattened images (graphs) with white background color.
  I am trying to make a movie out of these files using ffmpeg. However, when I use ffmpeg, everything white in the images become black in the movie. And everything black remains the same. The command I used is :

  The command I use is :

  ffmpeg -pix_fmt yuv420p -r 8 -f image2 -pattern_type glob -i
  ’*.00.png’ movie.mp4

• ffmpeg : Output to the same folder as source with recursive input ?

  22 octobre 2015, par t3hPeNgU1NoFd00m

  I have a lot of gifs I want converted to webms in many sub directories, and I have this script which will do it, but it will output to the directory where the script is located :

  for /r %%a in ("*.gif") do ffmpeg -i "%%a" -c:v libvpx -crf 12 -b:v 4000k "%%~na.webm"
  
  pause

  I’ve tried a bunch of things, but I can’t figure out how to get the output to land in the same sub directory as the input file so I can maintain the folder structure.

  Edit : it’s a Windows batch file I’m using.