On 2016-08-24 08:49, JamesH wrote: > Aloha from Hawaii! > > I'm using a Raspberry Pi and am trying to make an alarm kinda thing... > > What I need to figure out how to do, and what I'm looking for help with > is > to figure out how to make sox (using the rec command I believe) record > into > a null file (meaning it doesn't really record, just goes through the > motions) until there's 5 seconds of silence... > > Being that the Raspberry Pi doesn't have any kind of audio capture > setup, I > was able to run a command that brought up a loopback audio device (that > command is "sudo modprobe snd-aloop") > > Now, how can I give sox a command to record from the loopback until > there's > 5 seconds of audio, or should I be looking at a different way of > checking if > the audio output of the raspberry pi has no sound? I think you might need to use sox to record to a real (or null) file & use the stat or stats effect to get output telling you what the peak sound level was in that five second period. Your alarm process would need to read the output of stat/stats to see whether the silence you want to find had occurred. I'm not sure how you limit sox so that it only produces a 5-second recording. If you needed, say, 1 second granularity you'd need to start five such processes at one second intervals so each one would look at a different (overlapping) 5-second period. That might also not be possible, for all I know. If you're unable to overlap 5-second periods you could do one-second analyses of sound levels and have a separate process that repeatedly looks at the last five such levels. -- Jeremy Nicoll - my opinions are my own ------------------------------------------------------------------------------ _______________________________________________ Sox-users mailing list Sox-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/sox-users
