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

Tags:

ffmpeg

audio

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?

like image 724
Ali Akber Avatar asked Feb 28 '17 11:02

Ali Akber


1 Answers

Try this:

ffmpeg -i audio.wav -af silencedetect=n=-50dB:d=0.5 -f null - 2>&1 | grep -Eo "silence_(start|end)" | tail -n 1 | grep "start" | wc -l

Output:

  • 1 - there is silence at the end
  • 0 - there is no silence at the end

Explanation: As I see in the silence case there is no silence_end at the end of log.

  1. 2>&1 - redirect stderr to stdin
  2. grep -Eo "silence_(start|end)" - filter log and keep only silence_start and silence_end from log. Each by new line.
  3. tail -n 1 - get last line. (if it is. So now we there are 3 cases of state: 'silence_start', 'silence_end', <empty>)
  4. grep "start" - keep line only if it contains start (2 cases: 'silence_start', <empty>)
  5. wc -l - get number of lines. (1 in 'silence_start' and 0 in <empty> case)
like image 95
Tarwirdur Turon Avatar answered Sep 28 '22 03:09

Tarwirdur Turon