---
title: vDSP_vdbcon
framework: Kernel
role: symbol
role_heading: Function
platforms: [macOS 10.4+]
path: kernel/1580001-vdsp_vdbcon
---

# vDSP_vdbcon

Vector convert power or amplitude to decibels; single precision.

## Declaration

```occ
void vDSP_vdbcon(const float *__A, vDSP_Stride __IA, const float *__B, float *__C, vDSP_Stride __IC, vDSP_Length __N, unsigned int __F);
```

## Parameters

- `__A`: Single-precision real input vector
- `__IA`: Stride for A
- `__B`: Pointer to single-precision real input scalar: zero reference
- `__C`: Single-precision real output vector
- `__IC`: Stride for C
- `__N`: The number of elements to process
- `__F`: Power (0) or amplitude (1) flag

## Discussion

Discussion Performs the following operation. α is 20 if F is 1, or 10 if F is 0.

Converts inputs from vector A to their decibel equivalents, calculated  in terms of power or amplitude according to flag F. As a relative reference point,  the value of input scalar *B is considered to be zero decibels.