Quick Start Guide

Installation

# Install dependencies
pip install -r requirements.txt

Basic Usage

1. Run Your First Test

python test_latency.py \
  --serial-number "SN001234" \
  --software-version "initial" \
  --comment "First test run"

What happens:

Auto-detects your Scarlett audio interface
Plays chirp signal and measures latency (5 measurements by default)
Records input/output on both channels
Calculates average, min, max, and standard deviation of latency
Saves results to test_results/YYYYMMDD_HHMMSS_latency/YYYYMMDD_HHMMSS_latency_results.yaml

2. View Results

# List all test results
python view_results.py --list

# View specific test (example)
python view_results.py test_results/20260226_123456_results.yaml

# View example result
python view_results.py example_test_result.yaml

3. Compare Different Units

Run multiple tests with different metadata:

# Test unit SN001234
python test_latency.py --serial-number "SN001234" --software-version "abc123"

# Test unit SN001235 with more measurements
python test_latency.py --serial-number "SN001235" --software-version "abc123" --measurements 10

# Compare by viewing both YAML files
python view_results.py test_results/20260226_120000_latency/20260226_120000_latency_results.yaml
python view_results.py test_results/20260226_130000_latency/20260226_130000_latency_results.yaml

Understanding the Output

Each latency test produces:

Average Latency (ms): Mean delay across all measurements
Min/Max Latency (ms): Range of measured values
Standard Deviation (ms): Consistency of measurements (lower is better)

Good values:

Latency: Depends on your system (audio interface typically < 10ms)
Standard Deviation: < 1ms (consistent measurements)
Latency: < 5 ms for loopback

Configuration

Edit config.yaml to customize test parameters:

audio:
  sample_rate: 44100
  channels: 2
  device_name: "Scarlett"

output:
  results_dir: "test_results"
  save_plots: true

python -c "import sounddevice as sd; print(sd.query_devices())"

Update device_name in config.yaml to match your device.

Troubleshooting

Audio device not found:

python -c "import sounddevice as sd; print(sd.query_devices())"