Newest 'ffmpeg' Questions - Stack Overflow

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• How to show audio bitrate information

  25 février 2014, par poc

  The ffmpeg only shows the video bitrate.How can I show the audio bitrate when I dump a streaming to file

  ffmpeg -i rtsp://172.19.1.40/live.sdp -acodec copy -vcodec copy export.avi

  

  

• How to get current frame number using ffmpeg c++

  25 février 2014, par John Simpson

  Usually, I use the below code to get the current frame number when decoding a video.

  while(av_read_frame(pFormatCtx, &packet)>=0) {
      if(packet.stream_index==videoStream) {
        // Decode video frame
        avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
        // Did we get a video frame?
        if(frameFinished) {
      int currentFrameNumber = pFrame->coded_picture_number; 
      }
      /* Free the packet that was allocated by av_read_frame*/
      av_free_packet(&packet);
    }
  

  Then, when I implemented seeking feature, I add av_seek_frame to seek to a desired position like this:

  if(av_seek_frame(pFormatCtx, -1, seekTarget, 0 )<0){
           LOG("log","error when seeking");
  }
  while(av_read_frame(pFormatCtx, &packet)>=0) {
          if(packet.stream_index==videoStream) {
            // Decode video frame
            avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
            // Did we get a video frame?
            if(frameFinished) {
          int currentFrameNumber = pFrame->coded_picture_number; 
          }
          /* Free the packet that was allocated by av_read_frame*/
          av_free_packet(&packet);
   }
  

  This is when the problem arises. pFrame->coded_picture_number returns incorrect value. My question is how I cam get the current frame given I have a decoded frame pFrame ?

• How to capture the commadline output from an app

  25 février 2014, par poc

  When I ran the command ffmpeg -i rtsp://172.19.1.40/live.sdp -acodec copy -vcodec copy lala.avi

  The ffmpeg will be continuously printing(refresh) the information fps and bitrate everyone second.

  How could I save those information using Python?

  

• How to sample `audio/video bit rate and fps ` every second on ffmepg or vlc

  25 février 2014, par poc

  I can dump the rtsp streaming into video file by

  ffmpeg -y -t 5  -i rtsp://172.19.1.42/live.sdp -acodec copy -vcodec copy lala.avi 
  

  Now, I wanna sample the streaming's audio/video bit rate and fps every second and dumpinto a text file,

  I can write a script for helping the work ,How could I get it?

• ffmpeg watermarking processing is very slow

  25 février 2014, par Hitesh Rohilla

  I am working on a video processing project and using ffmpeg for watermarking. I achieve exactly what i want but the problem is that the process is very very slow.

  I am using a Intel Smart 2nd gen family Core-i5 Processor with 4GB RAM on a 32 bit operating system Microsoft Windows-8 on a 64-bit CPU.

  I tried watermarking a video [mp4] of length 1:30 Min. size of file is 1.5GB

  Whole process accomplish in 3 Hrs to watermark my video file and what i noticed while process is that ffmpeg was processing 28 frames per sec first and then later it slow down up to 20 frames per second. a normal human watch video with frame rate of 30 frame per second and process was even slower then this that's why it took more time [3 Hrs] then the actual length of video itself [1:33]

  What i think to make process efficient is to use ffmpeg Watermarking Source Code and modify it somewhat...

  I want to ask if someone have achieve fast watermarking before by any other way or have modified this code to achieve faster process in order to save my time...