📊 Quality Metrics Catalog¶

Complete catalog of all metrics available in AudioLab Quality Metrics system.

Audio Quality Metrics¶

Distortion Metrics¶

Metric	Type	Unit	Direction	Standard	Target (Professional)
`audio.thd_percent`	Gauge	%	Lower Better	IEEE 1057	< 0.001%
`audio.thd_db`	Gauge	dB	Lower Better	IEEE 1057	< -100 dB
`audio.thd_plus_noise_percent`	Gauge	%	Lower Better	IEEE 1057	< 0.003%
`audio.imd_smpte_percent`	Gauge	%	Lower Better	SMPTE RP120	< 0.001%

Noise Metrics¶

Metric	Type	Unit	Direction	Target
`audio.snr_db`	Gauge	dB	Higher Better	> 120 dB
`audio.dynamic_range_db`	Gauge	dB	Higher Better	> 120 dB
`audio.noise_floor_dbfs`	Gauge	dBFS	Lower Better	< -120 dBFS

Frequency Response¶

Metric	Type	Unit	Direction	Target
`audio.frequency_response_deviation_db`	Gauge	dB	Lower Better	±0.1 dB
`audio.phase_response_deviation_deg`	Gauge	°	Lower Better	< 1°
`audio.group_delay_ms`	Gauge	ms	Lower Better	< 1 ms

Psychoacoustic Metrics¶

Metric	Type	Unit	Direction	Standard	Target
`audio.lufs_integrated`	Gauge	LUFS	Neutral	ITU-R BS.1770-4	-23 ± 1 (broadcast)
`audio.lufs_momentary`	Gauge	LUFS	Neutral	ITU-R BS.1770-4	< -20
`audio.lufs_short_term`	Gauge	LUFS	Neutral	ITU-R BS.1770-4	< -18
`audio.true_peak_dbtp`	Gauge	dBTP	Lower Better	ITU-R BS.1770-4	< -1 dBTP
`audio.loudness_range_lu`	Gauge	LU	Lower Better	EBU R128	< 20 LU

Performance Metrics¶

CPU Metrics¶

Metric	Type	Unit	Direction	Target
`cpu.usage_percent`	Gauge	%	Lower Better	< 50%
`cpu.usage_per_voice`	Gauge	%	Lower Better	< 0.5%
`cpu.cycles_per_sample`	Histogram	cycles	Lower Better	< 100
`cpu.ipc`	Gauge	instructions/cycle	Higher Better	> 2.0

Memory Metrics¶

Metric	Type	Unit	Direction	Target
`memory.usage_bytes`	Gauge	bytes	Lower Better	< 100 MB
`memory.allocated_total_bytes`	Counter	bytes	-	-
`memory.peak_usage_bytes`	Gauge	bytes	Lower Better	-
`memory.cache_hit_rate_percent`	Gauge	%	Higher Better	> 95%

Latency Metrics¶

Metric	Type	Unit	Direction	Target
`latency.processing_ms`	Histogram	ms	Lower Better	< 10 ms
`latency.roundtrip_ms`	Histogram	ms	Lower Better	< 20 ms
`latency.buffer_callback_us`	Histogram	µs	Lower Better	< 1000 µs
`latency.p99_ms`	Gauge	ms	Lower Better	< 15 ms

Throughput Metrics¶

Metric	Type	Unit	Direction	Target
`throughput.samples_per_second`	Gauge	samples/s	Higher Better	> 48000
`throughput.buffers_per_second`	Counter	buffers/s	Higher Better	-
`throughput.voices_rendered`	Counter	voices	-	-

Code Quality Metrics¶

Complexity Metrics¶

Metric	Type	Unit	Direction	Target
`code.cyclomatic_complexity`	Gauge	-	Lower Better	< 10
`code.cognitive_complexity`	Gauge	-	Lower Better	< 15
`code.halstead_difficulty`	Gauge	-	Lower Better	< 20
`code.maintainability_index`	Gauge	-	Higher Better	> 70

Coverage Metrics¶

Metric	Type	Unit	Direction	Target
`code.line_coverage_percent`	Gauge	%	Higher Better	> 90%
`code.branch_coverage_percent`	Gauge	%	Higher Better	> 85%
`code.mutation_coverage_percent`	Gauge	%	Higher Better	> 80%

Quality Metrics¶

Metric	Type	Unit	Direction	Target
`code.lcom`	Gauge	-	Lower Better	< 0.5
`code.coupling`	Gauge	-	Lower Better	< 5
`code.technical_debt_hours`	Gauge	hours	Lower Better	< 100
`code.code_smells_count`	Gauge	-	Lower Better	0

System Metrics¶

Plugin Metrics¶

Metric	Type	Unit	Direction	Target
`plugin.instantiation_ms`	Histogram	ms	Lower Better	< 500 ms
`plugin.preset_load_ms`	Histogram	ms	Lower Better	< 100 ms
`plugin.state_save_ms`	Histogram	ms	Lower Better	< 50 ms

Stability Metrics¶

Metric	Type	Unit	Direction	Target
`stability.crashes_total`	Counter	-	Lower Better	0
`stability.audio_dropouts_total`	Counter	-	Lower Better	0
`stability.uptime_hours`	Counter	hours	Higher Better	-

Usage Examples¶

Record a Metric¶

auto thd_metric = REGISTER_GAUGE(
    "audio.thd_percent",
    "Total Harmonic Distortion",
    "%",
    MetricDirection::LOWER_BETTER
);

thd_metric->record(0.0008);  // 0.0008%

Query Histogram Statistics¶

auto latency = MetricRegistry::getInstance().getMetric("latency.processing_ms");
auto hist = std::dynamic_pointer_cast<HistogramMetric>(latency);

std::cout << "P50: " << hist->getP50() << " ms\n";
std::cout << "P95: " << hist->getP95() << " ms\n";
std::cout << "P99: " << hist->getP99() << " ms\n";

Check Against Standards¶

bool meets_standard = meetsProfessionalTHDStandard(thd_percent);

Total Metrics Defined: 50+ Coverage: Audio Quality, Performance, Code Quality, System