BlockStatistics
Overview
Computes statistics of a block of samples
Discussion
This module calculates statistics of the input signal on a block-by-block basis. The input pin can have an arbitrary number of interleaved channels and the calculation occurs over all channels. The output pin has a single channel 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 block-by-block basis and stored in the instantaneousValue variable. The module is stateless and the statistic is recomputed for each block.
An optional constructor argument OUTPUTVALUE specifies whether the computed statistic should be output on an output pin. By default, OUTPUTVALUE=0 and the statistic is only stored internally in instantaneousValue. If OUTPUTVALUE=1 then the value of the statistic is output of the first output pin as a floating-point value. If OUTPUTVALUE=2 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 OUTPUTVALUE=2 only makes sense when statisticType=0 (max), 1 (min), or 2 (maxAbs).
Type Definition
typedef struct _ModuleBlockStatistics
{
ModuleInstanceDescriptor instance; // Common Audio Weaver module instance structure
INT32 statisticsType; // Type of statistics calculated.
FLOAT32 instantaneousValue; // Instantaneous output value.
} ModuleBlockStatisticsClass;
Variables
Properties
Name | Type | Usage | isHidden | Default value | Range | Units |
statisticsType | int | parameter | 0 | 0 | 0:9 | |
instantaneousValue | float | state | 0 | 0 | -10:10 |
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_statistics_module.m
M=block_statistics_module(NAME, OUTPUTVALUE, SAMPLERATE)
This module calculates statistics of the input signal on a block-by-
block basis. The type of statistics calculated is determined by
the statisticsType parameter. The computed value is stored in the
internal state variable instantaneousValue.
Arguments:
NAME - name of the module.
OUTPUTVALUE - Integer value which specifies whether the module has
an output pin. If OUTPUTVALUE=0, then the module has no output
pin. If OUTPUTVALUE=1 (the default), then the instantaneousValue
variable is output as a single sample on the first output pin.
If OUTPUTVALUE=2 then the module has a second output pin
containing the index at which the value occurred. Outputting the
index only makes sense for Max, Min, and MaxAbs statistics. In
all other cases, index = -1.
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.%