C / C++ / MFC

Long SumOfSamples = 0
Long SumOfSquaredDifferences = 0

// First determine the average sound level
// I don't know whether audio data is represented as unsigned or signed values - 
// you may have to look at the values in a data block to decide what to use!
For count = 1 to numberSamplesInBlock
	SumOfSamples += soundSample[count]

AverageSoundLevel = SumOfSamples / numberSamplesInBlock

// Now work out the average of how far every sample is from the average level
For count = 1 to numberSamplesInBlock
	ThisSampleDifference = sample[count] - AverageSoundLevel
	SumOfSquaredDifferences += ThisSampleDifference * ThisSampleDifference

AverageDifference = SquareRoot(SumOfSquaredDifferences) / numberSamplesInBlock

// Now decide whether the data block is loud or soft or in-between
If AverageDifference < softSoundThreshold
	Display "The Sound Is Soft"
Else if AverageDifference > loudSoundThreshold
	Display "The Sound Is Loud"
Else
	Display "The Sound Is Between Soft And Loud Limits"

// Determine the softSoundThreshold and loudSoundThreshold by recording 
// sounds using the microphone and looking at their AverageDifference values

V_shr wrote:

thanks a lot , it was useful to me