The VideoLAN Forums

Posted: **12 Mar 2011 15:20**

My objective is to transcode audio to http streaming while at the same time applying equalization.

What is the correct syntax for specifying the parameters of either the 10-band EQ or the parametric EQ filter? I feel like I'm close, but these don't work (the audio passes through but is not modified by the equalizer):

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"c:\Program Files\VideoLAN\VLC\vlc.exe" input.mp3 :sout=#transcode{afilter=equalizer{bands="20 15 0 -20 -20 -20 -20 -20 -20 -20",twopass=true},vcodec=none,acodec=mp3,ab=320,channels=2,samplerate=44100}:http{mux=raw,dst=:8080/}

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"c:\Program Files\VideoLAN\VLC\vlc.exe" input.mp3 :sout=#transcode{afilter=param_eq{lowf=40,lowgain=-20,highf=8000,highgain=20,f1=60,q1=10,gain1=-20,twopass=1},vcodec=none,acodec=mp3,ab=320,channels=2,samplerate=44100}:http{mux=raw,dst=:8080/}

I've tried several different variations to no avail. Documentation doesn't seem to cover the case where one wants to apply EQ during a transcode.

The closest I've gotten is just

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"c:\Program Files\VideoLAN\VLC\vlc.exe" input.mp3 :sout=#transcode{afilter=equalizer},vcodec=none,acodec=mp3,ab=320,channels=2,samplerate=44100}:http{mux=raw,dst=:8080/}

but this then uses whatever 10-band EQ settings I've saved in preferences, and I'd much rather specify it on the command line as this particular application calls for a severe low-end rolloff that I won't want to use for playing anything else. Also, I'd rather use the parametric EQ to notch out a specific rumble frequency.

Note: In my examples above I'm streaming from a mp3 file, but ultimately I will be streaming from dshow input, so pre-processing the mp3 is not a viable workaround. Also, the specific EQ parameters I'm using for demonstration are deliberately severe so that I can easily discern between equalized and un-equalized audio output.

Posted: **13 Mar 2011 04:50**

This example is for video, but the "equalizer" component is the same:

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C:\Progra~1\VideoLAN\VLC\vlc -vvv "C:\video.wmv" --sout=#transcode{afilter=#equalizer{preamp=20,preset=flat},vcodec=h264,vb=0,scale=0,width=0,height=0,acodec=aac,ab=128,channels=2,samplerate=44100,deinterlace}:standard{access=file,mux=ts,dst="C:\test.mp4"}

Posted: **16 Mar 2011 12:31**

I have the same problem but with multicast stream. I tried the code below but nothing take effect on the output multicast stream:

1rst => :sout=#transcode{vcodec=none,acodec=mpga,ab=128,channels=2,samplerate=44100}:std{access=udp,mux=ts,dst=239.0.0.1:5501} --equalizer-preset=dance --equalizer-preamp=-20 --equalizer-bands=0 0 0 0 0 0 0 0 0 0 --sout-transcode-afilter=equalizer

2nd=> :sout=#transcode{afilter=#equalizer{preamp=20,preset=dance},vcodec=mp2v,vb=800,scale=1,acodec=mpga,ab=128,channels=2}:duplicate{dst=std{access=udp,mux=ts,dst=239.0.0.1:5501}}

Any idea? I'm doing something wrong?

Tks

Posted: **16 Mar 2011 18:13**

I couldn't really make the bands thing work either (even with adding the # in front of #equalizer). Does that parameter need to go in double- or single-quotes, maybe?

Posted: **26 Mar 2011 23:19**

Just wanted to tell you that I did get this to work once. Can't remember if it was with vlc-1.1.7 or the daily snapshot vlc-1.2.0-git-20110311-1521. It's not optimal since the best thing would be to specify all filter params in the transcode call.

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:sout=#transcode{afilter=equalizer,vcodec=mp2v,vb=800,scale=1,acodec=mpga,ab=128,channels=2,samplerate=44100}:http{mux=ts,dst=:8080/} :no-sout-rtp-sap :no-sout-standard-sap :ttl=1 :sout-keep

vlc --audio-filter equalizer --equalizer-preamp=-20

(Notice --audio-filter equalizer to enable the eq at start-up).

The VideoLAN Forums

How to specifiy EQ params in command line?

How to specifiy EQ params in command line?

Re: How to specifiy EQ params in command line?

Re: How to specifiy EQ params in command line?

Re: How to specifiy EQ params in command line?

Re: How to specifiy EQ params in command line?