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• Replace blank spaces from arguments to run command

  12 août 2017, par ChrisBlp

  I’m using Runtime.getRuntime.exec(String) to cut some songs with ffmpeg.
  But when my song has a name with a blankspace it doesn’t work ...

  So before I cut the song, I want to replace every blank space of my songs by "\ ".

  I did that :

  String in = directory+songs.get(i);
  
  String out = directory+"trimed_"+songs.get(i);
  
  in.replaceAll(" "," \\ ");
  
  out.replaceAll(" ", "\\ ");
  
  String str = "ffmpeg -t 1 -i "+in+" -vcodec copy "+out;
  
  Runtime.getRuntime().exec(str);

  But it doesn’t replace anything at all when I print str, am I missing something ?

  Update : I tried every ideas given bellow and I didn’t find a way to fix the problem. Hence, I replaced the blankspaces by "_" and it’s working great.

• FFmpeg : How to create dynamic volume changes in an audio file ?

  14 octobre 2018, par Ankush

  I am working on a project in which I need to change the volume of an audio file dynamically.

  Let’s say, I have an audio file with name xyz.mp3 (20 - seconds audio file).
  I need to set the volume in it like :

  Time Range (in Seconds)     ||     Volume Percentage (in %)
  
  -------------------------------------------------------------------    
  
      0 - 4                   ||           100
  
                              ||
  
      4 - 8                   ||    change from 100 - 20 (dynamically)
  
                              ||
  
      8 - 12                  ||           20
  
                              ||           
  
      12 - 16                 ||    change from 20 - 100 (dynalically)
  
                              ||
  
      16 - 20                 ||           100       

  Now, I know that to change the volume for a particular time in audio, I can use the following command :

  ffmpeg -i in.mp3 -af volume=20:enable='between(t,8,12)' out.mp3

  but when I use volume effect, it does not change the volume dynamically. It just straightly change volume from 100 to 20 and not change it like fading.

  and When I use afade command like :

  ffmpeg -i in.mp3 -af afade=t=in:ss=4:d=8,afade=t=out:st=12:d=16 out.mp3

  or

  ffmpeg -i in.mp3 -af afade=enable='between(t,4,8)':t=in:ss=4:d=4,afade=enable='between(t,12,16)':t=out:st=12:d=4 out.mp3

  but it looks that afade does not work multiple times even when I am using ffmpeg 3.0.1 version.

  As afade only works single time, I had also split my audio into parts of 4 second and add fade effects to it and then combine them again, but there is some milliseconds gap comes between each clip. Does anyone know a better way to do it ? Please help me...

  Update 1 :

  Here is that code I used :

  "volume='" +
  
              "between(t,0,8)+(1-0.8*(t-8)/4)*" +        // full
  
              "between(t,8.01,11.99)+0.1*" +             // change from HIGH -> LOW
  
              "between(t,12,16)+(0.1+0.8*(t-16)/4)*" +   // low
  
              "between(t,16.01,19.99)+1*" +              // change from LOW -> HIGH   -
  
              "between(t,20,24)+(1-0.8*(t-24)/4)*" +     // full
  
              "between(t,24.01,27.99)+0.1*"+             // change from HIGH -> LOW   -
  
              "between(t,28,32)+(0.1+0.8*(t-32)/4)*" +   // low
  
              "between(t,32.01,35.99)+1*" +              // change from LOW -> HIGH  -
  
              "between(t,36,40)+(1-0.8*(t-40)/4)*" +     // full
  
              "between(t,40.01,43.99)+0.1*"+             // change from HIGH -> LOW   -
  
              "between(t,44,48)+(0.1+0.8*(t-48)/4)*" +   // low
  
              "between(t,48.01,51.99)+" +                // change from LOW -> HIGH -
  
              "between(t,52,56)" +                       // high
  
              "':eval=frame";

  In this code, I got a small (some milliseconds gap) at those places where I initialize the audio to change the volume

  Update 2
  Ok I got it, I just need to change the time values like 19.99 to 19.9999 and 16.01 to 16.0001 and it solve the problem. Thank You Gyaan Sir.

• Rescalling or dynamic scalling images in Ffmpeg in a video

  23 janvier 2021, par najam ulhassan

  I tried to create a video using multiple images having different scales or sizes or (height*widths) using Mobile-FFmpeg #
  
I am using this code script to get the required result :

  


  val filterStringBuilder1 = StringBuilder()<br />&#xA;filterStringBuilder1.append(listOfImages)<br />&#xA;filterStringBuilder1.append("-filter_complex ")<br />&#xA;filterStringBuilder1.append(<br />&#xA;            "[0:v]scale=100:140:force_original_aspect_ratio=decrease,pad=100:140:(ow-iw)/2:(oh-ih)/2,setsar=1,fade=t=out:st=4:d=1[v0];" &#x2B;<br />&#xA;            "[1:v]scale=180:120:force_original_aspect_ratio=decrease,pad=180:120:(ow-iw)/2:(oh-ih)/2,setsar=1,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1[v1];" &#x2B;<br />&#xA;            "[2:v]scale=120:180:force_original_aspect_ratio=decrease,pad=120:180:(ow-iw)/2:(oh-ih)/2,setsar=1,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1[v2];" &#x2B;<br />&#xA;            "[v0][v1][v2]concat=n=3:v=1:a=0,format=yuv420p[v]")<br />&#xA;    filterStringBuilder1.append(" -map")<br />&#xA;    filterStringBuilder1.append(" [v] ")<br />&#xA;    filterStringBuilder1.append("-aspect 16:9 ")<br />&#xA;    filterStringBuilder1.append(finalVideo.absolutePath)<br />&#xA;    FFmpeg.execute(filterStringBuilder1.toString())<br />&#xA;

  

  
But finding following logcat error :

  


   E/mobile-ffmpeg: [Parsed_concat_14 @ 0x748fc98bc0] <br />&#xA; E/mobile-ffmpeg: Input link in1:v0 parameters (size 180x120, SAR 1:1) do not match the corresponding <br />output link in0:v0 parameters (100x140, SAR 1:1)<br />&#xA; E/mobile-ffmpeg: [Parsed_concat_14 @ 0x748fc98bc0] <br />&#xA; E/mobile-ffmpeg: Failed to configure output pad on Parsed_concat_14<br />&#xA; E/mobile-ffmpeg: Error reinitializing filters!<br />&#xA; E/mobile-ffmpeg: Failed to inject frame into filter network: Invalid argument<br />&#xA; E/mobile-ffmpeg: Error while processing the decoded data for stream #2:0<br />&#xA;