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?
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 endExplanation:
As I see in the silence case there is no silence_end
at the end of log.
2>&1
- redirect stderr
to stdin
grep -Eo "silence_(start|end)"
- filter log and keep only silence_start
and silence_end
from log. Each by new line.tail -n 1
- get last line. (if it is. So now we there are 3 cases of state: 'silence_start'
, 'silence_end'
, <empty>
)
grep "start"
- keep line only if it contains start
(2 cases: 'silence_start'
, <empty>
)
wc -l
- get number of lines. (1
in 'silence_start'
and 0
in <empty>
case)
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