atsa

ATSA analysis utility for ATS spectral analysis

The atsa utility performs ATS (Analysis-Transformation-Synthesis) spectral analysis on sound files. ATS is a sinusoidal modeling technique that separates sounds into deterministic (tonal) and stochastic (noise) components.

Syntax

atsa soundfile atsfile [flags]

Arguments

• soundfile - Input sound file to analyze
• atsfile - Output ATS analysis file

Options

Time and frequency range

Option	Description	Default
-b	Start time in seconds	0.0
-e	Duration in seconds (or end time)	0.0 (entire file)
-l	Lowest frequency in Hertz	20.0
-H	Highest frequency in Hertz	20000.0

Analysis parameters

Option	Description	Default
-d	Frequency deviation (ratio of partial frequency)	0.1
-c	Window cycles	4
-w	Window type (0=Blackman, 1=Blackman-Harris, 2=Hamming, 3=von Hann)	1
-h	Hop size (ratio of window size)	0.25
-m	Lowest magnitude in dB	-60.0

Tracking parameters

Option	Description	Default
-t	Track length in frames	3
-s	Minimum segment length in frames	3
-g	Minimum gap length in frames	3
-T	SMR (Signal-to-Mask Ratio) threshold in dB SPL	30.0
-S	Minimum segment SMR in dB SPL	60.0
-P	Last peak contribution (ratio)	0.0
-M	SMR contribution (ratio)	0.5

Output format

Option	Description	Default
-F	File type: 1 = amplitude and frequency only 2 = amplitude, frequency, and phase 3 = amplitude, frequency, and noise 4 = amplitude, frequency, phase, and noise	4

Examples

Basic analysis

atsa input.wav output.ats

Analysis with custom frequency range

atsa input.wav output.ats -l 100 -H 8000

High-quality analysis with fine time resolution

atsa input.wav output.ats -c 8 -h 0.125 -m -80

Analysis without noise residual

atsa input.wav output.ats -F 2

Analyze specific time segment

atsa input.wav output.ats -b 2.5 -e 10.0

Output file format

The ATS file contains:

• Type 1: Amplitude and frequency tracks for each partial
• Type 2: Adds phase information for phase-coherent resynthesis
• Type 3: Adds critical-band noise energy for stochastic residual
• Type 4: Complete analysis with all parameters

Technical details

Window types

• Blackman (0): Good frequency resolution with moderate sidelobe rejection
• Blackman-Harris (1): Excellent sidelobe rejection (default, recommended)
• Hamming (2): Better frequency resolution but higher sidelobes
• von Hann (3): Standard window with moderate characteristics

Analysis parameters

• Frequency deviation: Controls how much a partial’s frequency can change between frames while still being tracked as the same partial
• Window cycles: Number of fundamental frequency cycles in the analysis window; affects frequency resolution
• Hop size: Determines time resolution; smaller values give better time resolution but slower analysis
• SMR threshold: Signal-to-Mask Ratio used to distinguish tonal components from noise

Using ATS files in Csound

ATS analysis files can be used with Csound opcodes:

• atsread - Read ATS analysis data
• atsadd - Additive synthesis from ATS data
• atssinnoi - Separate synthesis of sinusoidal and noise components
• atsinfo - Get information about an ATS file
• atscross - Cross-synthesis between ATS files

Related utilities

• pvanal - Phase vocoder analysis
• hetro - Heterodyne analysis
• lpanal - LPC analysis