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• how to add watermark and subtitles to multi video in the same time with ffmpeg

  19 novembre 2020, par Fady Sawairas

  hello i am using ffmpeg to add watermark to multi video with this code

  


  for %i in ("C :\Users\fady\Downloads\Fady\new2*.mp4") do ffmpeg -i "%i" -i C :\Users\fady\Downloads\convert\cima2u.png -preset ultrafast -filter_complex "[0]scale=1280:720 :-2[bg] ;[bg][1]overlay=main_w-overlay_w-10:10" -b:v 1000k "C :\Users\fady\Downloads\Fady\new\new2% ni.mp4"

  


  now i want to add subtitles to multi video at the same time
like video1.mp4 with subtitle video1.srt
video2.mp4 with subtitle video2.srt
video3.mp4 with subtitle video3.srt

  


  i am wondering is there any code to make it with ffmpeg one time with all video in one folder or i must make each video alone ?

  


• create multiple movie thumbnails using ffmpeg (one at a time) failing

  2 septembre 2013, par Christopher Johnson

  I'm using this small bit of code to create thumbnails of videos being uploaded to my site :

  public static void GetThumbnail(string video, string thumbnail)
  
  {
  
      var cmd = "ffmpeg  -itsoffset -1  -i " + '"' + video + '"' + " -vcodec mjpeg -vframes 1 -an -f rawvideo -s 320x240 " + '"' + thumbnail + '"';
  
      var startInfo = new ProcessStartInfo
  
      {
  
          WindowStyle = ProcessWindowStyle.Hidden,
  
          FileName = "cmd.exe",
  
          Arguments = "/C " + cmd
  
      };
  
  
  
      var process = new Process
  
      {
  
          StartInfo = startInfo
  
      };
  
  
  
      process.Start();
  
  }

  I'm uploading the videos one at a time asynchronously. The first video thumbnail gets created just fine, but each subsequent one does not get created. I've noticed that if I try to delete subsequent videos from the file system, it says it can not delete them because they are in use by ffmpeg. I can delete the first one that finished processing just fine. I have to kill the ffmpeg process from task manager for all of the others that it's holding open. Why is ffmpeg only working the first time through and then holding the video's open in an open process afterwards ?

  I also tried creating multiple thumbnails one at a time from the command prompt and that worked fine (the process does not stay open either).

  What am I missing in my c# code to make sure the process finishes, and then terminates ?

• FFMPEG streaming RTP : time base not set

  15 novembre 2016, par Managarm

  I’m trying to create a small demo to get a feeling for streaming programmatically with ffmpeg. I’m using the code from this question as a basis. I can compile my code, but when I try to run it I always get this error :

  [rtp @ 0xbeb480] time base not set

  The thing is, I have set the time base parameters. I even tried setting them for the stream (and the codec associated with the stream) as well, even though this should not be necessary as far as I understand it. This is the relevant section in my code :

  AVCodec* codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  AVCodecContext* c = avcodec_alloc_context3(codec);
  
  c->pix_fmt = AV_PIX_FMT_YUV420P;
  
  c->flags = CODEC_FLAG_GLOBAL_HEADER;
  
  c->width = WIDTH;
  
  c->height = HEIGHT;
  
  c->time_base.den = FPS;
  
  c->time_base.num = 1;
  
  c->gop_size = FPS;
  
  c->bit_rate = BITRATE;
  
  
  
  avcodec_open2(c, codec, NULL);
  
  struct AVStream* stream = avformat_new_stream(avctx, codec);
  
  
  
  // TODO: causes an error
  
  avformat_write_header(avctx, NULL);

  The error occurs when calling "avformat_write_header" near the end. All methods that can fail (like avcodec_open2) are checked, I just removed the checks to make the code more readable.

  Digging through google and the ffmpeg source code didn’t yield any useful results. I think it’s really basic, but I’m stuck. Who can help me ?