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• How to detect the silence at the end of an audio file ?

  1er mars 2017, par Ali Akber

  I am trying to detect silence at the end of an audio file.
  I have made some progress with ffmpeg library. Here I used silencedetect to list all the silences in an audio file.

  ffmpeg -i audio.wav -af silencedetect=n=-50dB:d=0.5 -f null - 2> /home/aliakber/log.txt

  Here is the output of the command :

  —With silence at the front and end of the audio file—

  [silencedetect @ 0x1043060] silence_start: 0.484979
  
  [silencedetect @ 0x1043060] silence_end: 1.36898 | silence_duration: 0.884
  
  [silencedetect @ 0x1043060] silence_start: 2.57298
  
  [silencedetect @ 0x1043060] silence_end: 3.48098 | silence_duration: 0.908
  
  [silencedetect @ 0x1043060] silence_start: 4.75698
  
  size=N/A time=00:00:05.56 bitrate=N/A

  —Without silence at the front and end of the audio file—

  [silencedetect @ 0x106fd60] silence_start: 0.353333
  
  [silencedetect @ 0x106fd60] silence_end: 1.25867 | silence_duration: 0.905333
  
  [silencedetect @ 0x106fd60] silence_start: 2.46533
  
  [silencedetect @ 0x106fd60] silence_end: 3.37067 | silence_duration: 0.905333
  
  size=N/A time=00:00:04.61 bitrate=N/A

  But I want something more flexible so that I can manipulate the output and do further task depending on the result.
  I want to get the output something like true or false. If there is a certain period of silence exists at the end of the audio file it will return true and false otherwise.

  Can someone suggest me an easy way to achieve this ?

• ffmpeg how to remove black borders when resizing an image

  3 juin 2021, par Mapg

  I am creating some thumbnails using FFmpeg and I see that some black borders are created when I resize them.

  


  I guess this is happening because the video source dimension doesn't match exactly the target dimension, so FFmpeg fills out the blank space with this black color.

  


  My question is ...

  


  Can I change this "black color" used by FFmpeg by default so I can match these extra borders added with the background of my application ?

  


  If this is not possible ...

  


  Can I convert these black borders to a transparent area so I can create a PNG to match my background which has a different color (a kind of light green)

  


  I have attached an example where you will see two black pixels height in the bottom zone of the picture.

  


  This is what I want to convert to transparent or being able to choose my own color.

  


  Any idea to solve this issue will be very helpful for me ?

  


  Thank you very much in advance !

  


  Mapg

  


  

  


• How to concate Multiple Audios with delay in single Video Using FFMPEG

  12 décembre 2022, par Makarand Burud

  I want ffmpeg command where in one Video i want to add mutlipes Audios with some delay in between two audios.
i tried with =ffmpeg -i video -i a2.mp3 -i a3.mp3 -i a4.mp3 -i a5.mp3 -i a6.mp3-filter_complex"[1]adelay=40000|40000[b] ;[2]adelay=66000|66000[c] ;[3]adelay=92000|92000[d] ;strong text
[4]adelay=118000|118000[e] ;[5]adelay=137000|137000[f] ; [0][b][c][d][e][f]amix=6" -c:v copy -c:a aac -map 0:v:0 -map 1:a:0 output.mp4