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• How to Mute audio after 10 Seconds for 2 seconds with ffmpeg filter volume?

  19 August 2020, by vinico2532

  I am using this command to mute audio :

  


  ffmpeg -i input.mp4 -af "volume=enable ='between(t,10,15)':volume=0, volume=enable ='between(t,20,25)':volume=0, volume=enable ='between(t,30,35)':volume=0, volume=enable ='between(t,40,45)':volume=0, volume=enable ='between(t,50,55)':volume=0" -c:v copy -c:a aac -b:a 192K output.mp4


  


  How can I repeat or loop this filter without writing it again and again?

  


  For example, this commands zooms video after specific seconds :

  


  ffmpeg -i input.mp4 -vf "zoompan=z='if(lte(mod(time,6),3),zoom+1.5,zoom-3)':x='iw/2-(iw/zoom)/2':y='ih/2-(ih/zoom)/2':d=1:fps=24" -c:v libx264 -crf 20 -preset:v ultrafast -profile:v high -g 60 -threads 2 -c:a aac -b:a 192K output.mp4


  


  How can I use volume filter like this to mute audio after specific seconds?

  


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

  14 October 2018, by 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.

• Revision 07711e9b27: Use hybrid RD and non-RD coding flow for key frame coding When block size is be

  4 December 2014, by Jingning Han

  Changed Paths:
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_speed_features.c

  
  
  Use hybrid RD and non-RD coding flow for key frame coding

  When block size is below 16x16, the encoder swap from non-RD to
  RD mode for key frame coding. This largely brough back the key
  frame compression performance. For vidyo1 at 1000 kbps, the key
  frame coding statistics are changed

  9978F, 34.183 dB, 36807 us -> 9838F, 35.020 dB, 61677 us

  As compared to the full RD case
  7187F, 34.930 dB, 214470 us

  The overall rtc set coding performance (single key frame setting)
  is improved by 1.5%.

  Change-Id: I78a4ecf025d7b24ec911e85be94e01da05e77878