This is brilliant and possibly the fastest reply I've had on a mail list in a very long time.
I'm back in work in the morning and will give it a go then and let you know how I get on. Thanks again for your time and help. Julian On Sun, 20 Feb 2022 at 11:59, Paul B Mahol <[email protected]> wrote: > On Sun, Feb 20, 2022 at 12:33 PM Julian Pilfold-Bagwell < > [email protected]> wrote: > > > Thanks for getting back. I was trying to insert a flag for noise > reduction > > into the command above but it always seemed to crash the moment I ran it. > > Part of my question is what the correct format would be. > > > > What flag? There is numerous examples on web how to use several audio > ffmpeg filters. > > Like agate, afftdn, afwtdn, anlmdn, arnndn, anlms, anlmf. > > agate audio filter is recommended if you are extreme novice to ffmpeg. > > For example one possible invocation, of myriad possible combinations is: > > /usr/bin/ffmpeg -f alsa -i hw:0,0 -af agate=threshold=-40dB -acodec > libmp3lame -ab 128k -ac 1 -content_type audio/mpeg -f mp3 > icecast://source:<password-removed>@172.20.0.75:8000/tannoy > > agate audio filter is there because it have very little latency and is very > fast, but not much useful than just filtering out only when background > noise is present and of certain signal to noise ratio. > > so threshold argument can be changed to actual dB of your background noise > typically captured. > > > > > > > > On Sun, 20 Feb 2022 at 11:12, Paul B Mahol <[email protected]> wrote: > > > > > On Sun, Feb 20, 2022 at 12:03 PM Julian Pilfold-Bagwell < > > > [email protected]> wrote: > > > > > > > Hi All, > > > > > > > > > > > > I'm trying to set up a tannoy system in our building using FFMPEG and > > > > Icecast. The server that is streaming is being fed from the 0db > > > recording > > > > output from an analogue amplifier that is wired up to an existing > 100v > > > > system and at the receiving end are PCs with active speakers fitted. > > > > > > > > The problem that I have is that when there's no audio input to the > > > tannoy, > > > > there's a background noise that is intrusive enough to play out > through > > > the > > > > speakers. I've been trying to use the noise reduction features in > > FFMPEG > > > > to reduce the noise but haven't managed to get rid of it. The > command > > > I'm > > > > running to run the system is: > > > > > > > > > > What noise reductions you tried? > > > > > > > > > > > > > > /usr/bin/ffmpeg -f alsa -i hw:0,0 -acodec libmp3lame -ab 128k -ac 1 > > > > -content_type audio/mpeg -f mp3 icecast://source:<password-removed>@ > > > > 172.20.0.75:8000/tannoy > > > > > > > > > > > > Can anyone let me know if this is possible or if there's any way I > > could > > > > implement something akin to a radio squelch that would just mute the > > > output > > > > when the input signal drops below a certain level. > > > > > > > > > > > > Thanks in advance, > > > > > > > > > > > > Jools > > > > _______________________________________________ > > > > ffmpeg-user mailing list > > > > [email protected] > > > > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > > > > > > > To unsubscribe, visit link above, or email > > > > [email protected] with subject "unsubscribe". > > > > > > > _______________________________________________ > > > ffmpeg-user mailing list > > > [email protected] > > > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > > > > > To unsubscribe, visit link above, or email > > > [email protected] with subject "unsubscribe". > > > > > _______________________________________________ > > ffmpeg-user mailing list > > [email protected] > > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > > > To unsubscribe, visit link above, or email > > [email protected] with subject "unsubscribe". > > > _______________________________________________ > ffmpeg-user mailing list > [email protected] > https://ffmpeg.org/mailman/listinfo/ffmpeg-user > > To unsubscribe, visit link above, or email > [email protected] with subject "unsubscribe". > _______________________________________________ ffmpeg-user mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
