Monitoring an audio stream at DVinfo.net

Greg Miller · September 4th, 2014, 02:36 AM

This is strictly an audio question ... no video involved.

I'm looking for a "box" with an internet connection, which can be configured to connect to the URL of a given audio stream (probably MP3, but other CODECS would be a plus), and then displays the actual level of the decoded audio (relative to 100% FS). It could be a "VU meter" display, a PPM display, or, better yet, a scalable waveform display.

I can achieve this now with two steps:
(1.) capture the stream as a file, using Total Recorder Pro (this does NOT use the soundcard, it captures the incoming data directly to the file)
(2.) view the file in editing software such as Audition, Audacity, or whatever.

I want a realtime solution that lets me punch in the URL and then examine the levels as the stream comes into the device. If this is done with software on a PC (rather than with a dedicated box) then it's important that the PC's soundcard settings should NOT affect the level / waveform that is displayed. Kind of like bridging an actual 6,000-ohm VU meter across a 600-ohm broadcast pair (with no intervening gain stage or attenuation) ... except looking at digital levels relative to 100% FS.

Does anybody know of a device, or software, with this sort of functionality?

Thanks in advance!

Seth Bloombaum · September 5th, 2014, 12:38 AM

I don't have a tested solution for you - sorry!

If it were me, i'd be looking at the minimum platform that offers a browser - that would be a tablet or smartphone or ipod touch.

Then you need recording software for it, say, TwistedWave Audio Editor for iOS.

Then... well, you run into the same problem you find on the mac or PC. The operating systems don't easily allow you to record/monitor the system sound output. But an app could be written for your needs if there is money for it. (not by me!) But maybe the paid version of TwistedWave works for this. Cost ya' $10 to find out.

On laptops you can sometimes use a mini-to-mini cable to connect the input to the output, but there are fequently level problems with this that would require resolution to do your measurements accurately.

There is a PC utility called Virtual Audio Cable that can enable the connection directly. This would be in the digital domain. (I'm not sure what exists for iOS or Android.)

If an editor can access the playback stream directly in the digital domain (this is likely post decode) then the input level meters of that editing sw or app should give you the measurements you want?

Or so it seems to me.

Greg Miller · September 5th, 2014, 08:23 AM

Quote:

Originally Posted by Seth Bloombaum

The operating systems don't easily allow you to record/monitor the system sound output.

Actually, Total Recorder is designed to do exactly that. It has its own set of drivers to accomplish it.

And the Pro version can also connect directly to an MP3 stream and capture the incoming data as a file on your local hard drive. So it is half way to solving my problem.

Unfortunately, Total Recorder does not have a good VU metering function, and while it has a crude timeline display of peak levels, it does not have a true waveform display. So it doesn't solve the problem in and of itself.

I think you're right: an app (or a PC application) could be written to solve this problem. To be really accurate, it would need to operate independent of the system sound card, so that there would be no possibility of changing a gain setting somewhere in the path. Unfortunately, I don't see that as a quick and practical solution to my present needs.

Thanks for your thoughts.

Richard Crowley · September 5th, 2014, 08:45 AM

There are many micro-PCs available < $150
Mini Barebone Systems, Booksize Barebone Systems - Newegg.com
There are several plug-in utilities for Windows that provide VU/PPM/spectrum/history display of the audio level.
But, indeed, there is a need for a straightforward app that will give you an unambiguous readout.

Steve House · September 5th, 2014, 03:56 PM

Would Wave's Dorrough Stereo Meter plug-in work for you?

http://www.waves.com/plugins/dorrough-stereo

Martijn Damen · September 9th, 2014, 01:07 AM

Hi Greg,

I think winamp could do the trick, as there are lots of plugins available for it, like a VU meter.
Stereo Analog VU Meter - RMS - Winamp
It seems to monitor the incoming audio level and is not affected by winamps volume or the soundcard volume.

September 4th, 2014, 02:36 AM	#1
Greg Miller Trustee Join Date: Jan 2011 Location: Pennsylvania Posts: 1,791	Monitoring an audio stream This is strictly an audio question ... no video involved. I'm looking for a "box" with an internet connection, which can be configured to connect to the URL of a given audio stream (probably MP3, but other CODECS would be a plus), and then displays the actual level of the decoded audio (relative to 100% FS). It could be a "VU meter" display, a PPM display, or, better yet, a scalable waveform display. I can achieve this now with two steps: (1.) capture the stream as a file, using Total Recorder Pro (this does NOT use the soundcard, it captures the incoming data directly to the file) (2.) view the file in editing software such as Audition, Audacity, or whatever. I want a realtime solution that lets me punch in the URL and then examine the levels as the stream comes into the device. If this is done with software on a PC (rather than with a dedicated box) then it's important that the PC's soundcard settings should NOT affect the level / waveform that is displayed. Kind of like bridging an actual 6,000-ohm VU meter across a 600-ohm broadcast pair (with no intervening gain stage or attenuation) ... except looking at digital levels relative to 100% FS. Does anybody know of a device, or software, with this sort of functionality? Thanks in advance!

September 5th, 2014, 12:38 AM	#2
Seth Bloombaum Inner Circle Join Date: Sep 2003 Location: Portland, Oregon Posts: 3,420	Re: Monitoring an audio stream I don't have a tested solution for you - sorry! If it were me, i'd be looking at the minimum platform that offers a browser - that would be a tablet or smartphone or ipod touch. Then you need recording software for it, say, TwistedWave Audio Editor for iOS. Then... well, you run into the same problem you find on the mac or PC. The operating systems don't easily allow you to record/monitor the system sound output. But an app could be written for your needs if there is money for it. (not by me!) But maybe the paid version of TwistedWave works for this. Cost ya' $10 to find out. On laptops you can sometimes use a mini-to-mini cable to connect the input to the output, but there are fequently level problems with this that would require resolution to do your measurements accurately. There is a PC utility called Virtual Audio Cable that can enable the connection directly. This would be in the digital domain. (I'm not sure what exists for iOS or Android.) If an editor can access the playback stream directly in the digital domain (this is likely post decode) then the input level meters of that editing sw or app should give you the measurements you want? Or so it seems to me. __________________ 30 years of pro media production. Vegas user since 1.0. Webcaster since 1997. Freelancer since 2000. College instructor since 2001.

September 5th, 2014, 08:45 AM	#4
Richard Crowley Trustee Join Date: Aug 2007 Location: Portland, Oregon Posts: 1,238	Re: Monitoring an audio stream There are many micro-PCs available < $150 Mini Barebone Systems, Booksize Barebone Systems - Newegg.com There are several plug-in utilities for Windows that provide VU/PPM/spectrum/history display of the audio level. But, indeed, there is a need for a straightforward app that will give you an unambiguous readout.

September 5th, 2014, 03:56 PM	#5
Steve House Inner Circle Join Date: Mar 2005 Location: Hamilton, Ontario, Canada Posts: 5,742	Re: Monitoring an audio stream Would Wave's Dorrough Stereo Meter plug-in work for you? http://www.waves.com/plugins/dorrough-stereo __________________ Good news, Cousins! This week's chocolate ration is 15 grams!

September 9th, 2014, 01:07 AM	#6
Martijn Damen Regular Crew Join Date: Jun 2014 Location: Valkenswaard, Netherlands Posts: 62	Re: Monitoring an audio stream Hi Greg, I think winamp could do the trick, as there are lots of plugins available for it, like a VU meter. Stereo Analog VU Meter - RMS - Winamp It seems to monitor the incoming audio level and is not affected by winamps volume or the soundcard volume.