Overview

Computes statistics per channel on a block-by-block basis

Discussion

This module calculates statistics of the input signal on a per-channel block-by-block basis. The input pin can have an arbitrary number of interleaved channels and the calculation occurs per channel. The output pin has the same number of channels as the input and a blockSize of 1.

For each block, one of the following values is calculated: maximum, minimum, maximum absolute value, mean, RMS, standard deviation, variance, or average energy. The parameter statisticsType specifies which statistic is computed: 0=maximum, 1=minimum, 2=maximum absolute value, 3=mean, 4=RMS, 5=standard deviation, 6=variance, 7=average energy, 8=sum, 9=sum of squares. The statistic is computed on a per-channel block-by-block basis. The module is stateless and the statistic is recomputed for each block.

An optional constructor argument OUTPUTINDEX specifies whether the computed statistic index (only for Max, Min, and MaxAbs) should be output on an output pin. By default, OUTPUTINDEX=0 and the module has a single output pin containing the statistic value. If OUTPUTINDEX=1 then the module has two output pins. The first output pin is the statistic value and the second output pin is the index at which the value occurs. Using OUTPUTINDEX=1 only makes sense when statisticType=0 (Max), 1 (Min), or 2 (MaxAbs).

By default, the sample rate of the output pin equals SRin / blocksize. There are some times when this computes the wrong sample rate and you can overwrite the output sample rate using the SAMPLERATE argument.

Type Definition

typedef struct _ModuleBlockStatisticsN
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 statisticsType;                         // Type of statistics calculated.
} ModuleBlockStatisticsNClass;

Variables

Properties

Pins

Input Pins

Name: in

Description: Audio input

Data type: float

Channel range: Unrestricted

Block size range: Unrestricted

Sample rate range: Unrestricted

Complex support: Real

Output Pins

Name: out

Description: Value

Data type: float

Name: index

Description: Index

Data type: int

MATLAB Usage

File Name: block_statisticsn_module.m

 M=block_statisticsn_module(NAME, OUTPUTINDEX, SAMPLERATE)
 This module calculates statistics of the input signal on block-by-block basis
 per channel.  This is similar to block_statistics_module.m but has a multichannel
 output. The type of statistics calculated is determined by the
 statisticsType parameter.  An optional per-channel index output for Max,
 Min, and MaxAbs statistics is available.
 Arguments:
    NAME - name of the module.
    OUTPUTINDEX - Integer value which specifies whether the module outputs
         the per-channel index of the location of the Max, Min, or
         MaxAbs statistic (if selected). By default, equals 0 and the module
         does not output the index.  Setting OUTPUTINDEX=1 causes a second
         output pin to appear and this outputs the sample index.
    SAMPLERATE - optional argument which specifies the output sample rate
      of the module.  By default, this is empty and the output sample
      rate is computed as inputSampleRate / blockSize.  In some cases,
      this sample rate is wrong and you can override it with this
      argument.