ambi_drc_internal.h File Reference

A frequency-dependent Ambisonic sound scene dynamic range compressor (DRC) More...

#include "ambi_drc.h"
#include "saf.h"
#include "saf_externals.h"

Go to the source code of this file.

Data Structures
struct	ambi_drc_data
	Main structure for ambi_drc. More...

Macros
#define	AMBI_DRC_FRAME_SIZE   ( 128 )
	Framesize, in time-domain samples.
#define	HOP_SIZE   ( 128 )
	STFT hop size.
#define	HYBRID_BANDS   ( HOP_SIZE + 5 )
	Number of frequency bands.
#define	TIME_SLOTS   ( AMBI_DRC_FRAME_SIZE / HOP_SIZE )
	Number of STFT timeslots.

Functions
float	ambi_drc_gainComputer (float xG, float T, float R, float W)
	The DRC gain computer.
float	ambi_drc_smoothPeakDetector (float xL, float yL_z1, float alpha_a, float alpha_r)
	The envelope detector.
void	ambi_drc_initTFT (void *const hAmbi)
	Initialise the filterbank used by ambi_drc.
void	ambi_drc_setInputOrder (SH_ORDERS inOrder, int *nSH)
	Sets the internal input order.

Detailed Description

A frequency-dependent Ambisonic sound scene dynamic range compressor (DRC)

The implementation can also keep track of the frequency-dependent gain factors for the omnidirectional component over time (for optional plotting). The design is based on the algorithm presented in [1].

The DRC gain factors per band are determined based on the omnidirectional component, which are then applied to all of the higher-order components; thus, the spatial information of the Ambisonic sound scene is retained (although, your perception of them may change due to the DRC).

See also

[1] McCormack, L., & Välimäki, V. (2017). "FFT-Based Dynamic Range Compression". in Proceedings of the 14th Sound and Music Computing Conference, July 5-8, Espoo, Finland.

Author

Leo McCormack

Date

07.01.2017

License

ISC

Definition in file ambi_drc_internal.h.

Macro Definition Documentation

AMBI_DRC_FRAME_SIZE

#define AMBI_DRC_FRAME_SIZE   ( 128 )

Framesize, in time-domain samples.

Definition at line 59 of file ambi_drc_internal.h.

HOP_SIZE

#define HOP_SIZE   ( 128 )

STFT hop size.

Definition at line 62 of file ambi_drc_internal.h.

HYBRID_BANDS

#define HYBRID_BANDS   ( HOP_SIZE + 5 )

Number of frequency bands.

Definition at line 63 of file ambi_drc_internal.h.

TIME_SLOTS

#define TIME_SLOTS   ( AMBI_DRC_FRAME_SIZE / HOP_SIZE )

Number of STFT timeslots.

Definition at line 64 of file ambi_drc_internal.h.

Function Documentation

ambi_drc_gainComputer()

float ambi_drc_gainComputer	(	float	xG,
		float	T,
		float	R,
		float	W )

The DRC gain computer.

Definition at line 46 of file ambi_drc_internal.c.

ambi_drc_initTFT()

void ambi_drc_initTFT

(

void *const

hAmbi

)

Initialise the filterbank used by ambi_drc.

Definition at line 87 of file ambi_drc_internal.c.

ambi_drc_setInputOrder()

void ambi_drc_setInputOrder	(	SH_ORDERS	inOrder,
		int *	nSH )

Sets the internal input order.

Definition at line 104 of file ambi_drc_internal.c.

ambi_drc_smoothPeakDetector()

float ambi_drc_smoothPeakDetector	(	float	xL,
		float	yL_z1,
		float	alpha_a,
		float	alpha_r )

The envelope detector.

Definition at line 70 of file ambi_drc_internal.c.