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• fluent-ffmpeg processing is very slow in Cloud Run

  18 août 2021, par Nazarii Kahaniak

  I am trying to merge multiple short videos in the container in Cloud Run using the node.js fluent-ffmpeg package. It takes 20 seconds max to merge videos locally. When I am making a request to clour run to merge the videos it processes them very slowly and after 30 minutes just stops (I assume that's because 1800 seconds timeout is set).
I tried to allocate to 2 CPUs with 8GB each but that didn't help. Within 30 minutes the video is processed by about 30 % as I can see in the cloud run logs.
Any feedback is appreciated !

  


• ffmpeg / Audacity channel splitting differences

  14 mars 2018, par Adrian Chromenko

  So I’m working on a speech to text project using Python and Google Cloud Services (for phone calls). The mp3s I receive have one voice playing in the left speaker, the other voice in the right speaker.

  So during testing, I manually split the original mp3 file into two WAV files (one for each channel, converted to mono). I did this splitting through Audacity. The accuracy was about 80-90%, which was perfect for my purposes.

  However, once I tried to automate the splitting using ffmpeg (more specifically : ffmpeg -i input_filename.mp3 -map_channel 0.0.0 left.wav -map_channel 0.0.1 right.wav), the accuracy dropped drastically.

  I’ve been experimenting for about a week now but I can’t get the accuracy up. For what it’s worth, the audio files sound identical to the human ear. I found that when I increase the volume of the output files, the accuracy gets better, but never as good as when I did the splitting with Audacity.

  I guess what I’m trying to ask is, what does Audacity do differently ?

  here are the sox -n stat results for each file :

  **Split with ffmpeg( 20-30% accuracy) : **

  Samples read:           1690560
  
  Length (seconds):    211.320000
  
  Scaled by:         2147483647.0
  
  Maximum amplitude:     0.433350
  
  Minimum amplitude:    -0.475739
  
  Midline amplitude:    -0.021194
  
  Mean    norm:          0.014808
  
  Mean    amplitude:    -0.000037
  
  RMS     amplitude:     0.028947
  
  Maximum delta:         0.333557
  
  Minimum delta:         0.000000
  
  Mean    delta:         0.009001
  
  RMS     delta:         0.017949
  
  Rough   frequency:          789
  
  Volume adjustment:        2.102

  Split with Audacity : (80-90% accuracy)

  Samples read:           1689984
  
  Length (seconds):    211.248000
  
  Scaled by:         2147483647.0
  
  Maximum amplitude:     0.217194
  
  Minimum amplitude:    -0.238373
  
  Midline amplitude:    -0.010590
  
  Mean    norm:          0.007423
  
  Mean    amplitude:    -0.000018
  
  RMS     amplitude:     0.014510
  
  Maximum delta:         0.167175
  
  Minimum delta:         0.000000
  
  Mean    delta:         0.004515
  
  RMS     delta:         0.008998
  
  Rough   frequency:          789
  
  Volume adjustment:        4.195

  original mp3 :

  Samples read:           3379968
  
  Length (seconds):    211.248000
  
  Scaled by:         2147483647.0
  
  Maximum amplitude:     1.000000
  
  Minimum amplitude:    -1.000000
  
  Midline amplitude:    -0.000000
  
  Mean    norm:          0.014124
  
  Mean    amplitude:    -0.000030
  
  RMS     amplitude:     0.047924
  
  Maximum delta:         1.015332
  
  Minimum delta:         0.000000
  
  Mean    delta:         0.027046
  
  RMS     delta:         0.067775
  
  Rough   frequency:         1800
  
  Volume adjustment:        1.000

  One thing that stands out to me is that the duration isn’t the same. Also the amplitudes. Can I instruct ffmpeg what the duration is when it is doing the splitting ? And can I change all the amplitudes to match the audacity file ? I’m not sure what to do to get to the 80% accuracy rate, but increasing volume seems to be the most promising solution so far.

  Any help would be greatly appreciated. I don’t have to use ffmpeg, but it seems like my only option, as Audacity isn’t scriptable.

• create video chunks with giving start and end time using ffmpeg and play those chunks sequentially with expiry time for each chunk using java

  4 octobre 2018, par JAVA Coder

  I have done like this I found it from the given link Just modified the code for start and end time and hard coded the times.
  Split video into smaller timed segments in Java

  @RequestMapping(value="/playVideo",method = RequestMethod.GET)
  
  @ResponseBody
  
  public void playVideo() {
  
      System.out.println("controller is working");
  
      int videoDurationSecs = 1800 ;
  
      int numberOfChunks = 5;//dynamically we can define according to video duration
  
       int chunkSize = videoDurationSecs/(numberOfChunks);
  
          int startSecs = 0;
  
          for (int i=0; i/*******Create video chunk*******//
  
  
  
              String startTime = convertSecsToTimeString(startSecs);
  
              int endSecs = startSecs+chunkSize;
  
              startSecs = endSecs+1; 
  
              if (endSecs > videoDurationSecs) {
  
                  //**make sure rounding does not mean we go beyond end of video**//
  
                  endSecs = videoDurationSecs;
  
              }
  
              String endTime = convertSecsToTimeString(endSecs);
  
  
  
              System.out.println("start time for-------------------->>>> "+startTime);
  
              System.out.println("end time for------------------->>>> "+endTime);
  
  
  
              /*
  
               * how to do this means send times for chunk and 
  
               * getting chunks and play them one by one like one video 
  
               * with expiry time for each
  
               */
  
  
  
  
  
              //Call ffmpeg to create this chunk of the video using a ffmpeg wrapper
  
              /*String argv[] = {"ffmpeg", "-i", videoPath, 
  
                      "-ss",startTime, "-t", endTime,
  
                      "-c","copy", segmentVideoPath[i]};
  
              int ffmpegWrapperReturnCode = ffmpegWrapper(argv);*/
  
          }
  
  
  
  
  
  }
  
  
  
  private String convertSecsToTimeString(int timeSeconds) {
  
      //Convert number of seconds into hours:mins:seconds string
  
      int hours = timeSeconds / 3600;
  
      int mins = (timeSeconds % 3600) / 60;
  
      int secs = timeSeconds % 60;
  
      String timeString = String.format("%02d:%02d:%02d", hours, mins, secs);
  
      return timeString;
  
  }

  }