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[negopus]

I think that an audio level meter located in the Action Window can be a great addition to Media Center. Personally I use external VST plug-ins for visualization, using loopback on the soundcard output. This is rather tricky. There should be a simpler native way to display audio in MC.

I have experimented a bit and I found that there are two positions where the audio signal monitoring can be interesting. (In both positions, the correct delay compensation should be applied, as MC uses a buffer. Without delay compensation the audio level display would be in advance of the sound of one buffer length.)

1) Pre-DSP studio: unprocessed (source) signal
2) Post-DSP studio: processed signal, that goes to the soundcard output

The level reference should change in the two situations, as Replay Gain (inside DSP studio) changes the signal level.

1) The pre-DSP studio meter should be calibrated in dBFS (dB Full Scale) and peak at 0 dBFS. It shows the original (source) signal.
2) The post-DSP studio meter should be calibrated in dB, peaking at +20 dB and with 0 dB reference 20 dB below the peak. Replay Gain works by changing the signal level in order to have the average RMS value 20 dB below full scale output.

Meters should display both RMS and peak value. The RMS value is related to the perceived loudness. It can be a fully colour vertical bar. (The RMS window can be 50 ms wide, in order to keep the meter responsive.) The peak value is more of interest for equipment. It can be a simple horizontal mark. (To have a good visual effect, the rise time should be immediate, the fall time should not be faster than 10-15 dB/sec). Both RMS and peak value can have a peak hold, displayed as a thin horizontal line. I found a (non-linear) scale that boosts the audio range from 0 dB to +20 dB, and makes the visual output more interesting.

Here are some screenshots (if the VillagePhoto server is working). The signal being played is a pink noise, with average RMS value 20 dB below full scale and peak value about 9 dB over the average. This is a calibration signal. Replay Gain is 0 in this case.
1) Pre DSP-studio

2) Post DSP-studio


In addition, more information about audio could be displayed: average RMS level (in dB), peak value (in dB), replay gain, channels, bit rate, compression algorithm.

Also, a "remote control" to DSP studio could be added. Not a complete replication of DSP studio. Just the ability to turn individual modules on or off.

I have dealt with stereo signals only. I think that multi-channel audio can be handled simply by adding more vertical bars.

I think that this level meter is applicable to internal decoders only. When audio is played through external decoders (codecs) the metering is not applicable, as MC has no control on the signal.

[GHammer]

I think it would be a cool addition.
I don't have a genuine use for the data, like mastering/recording, but I'm a product of the 60s. I am fascinated by shiny flashing things.