### Get Configured Channels

Source: https://docs.rs/ebur128/latest/ebur128/struct.EbuR128.html?search=std%3A%3Avec

Retrieves the configured number of audio channels.

```rust
pub fn channels(&self) -> u32
```

--------------------------------

### Get Rate

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Retrieves the configured audio sample rate.

```APIDOC
## rate

### Description
Gets the configured sample rate.

### Method
`rate(&self) -> u32`

### Returns
The sample rate.
```

--------------------------------

### Get Configured Mode

Source: https://docs.rs/ebur128/latest/ebur128/struct.EbuR128.html?search=std%3A%3Avec

Retrieves the currently configured loudness analysis mode.

```rust
pub fn mode(&self) -> Mode
```

--------------------------------

### Get Configured Sample Rate

Source: https://docs.rs/ebur128/latest/ebur128/struct.EbuR128.html?search=std%3A%3Avec

Retrieves the configured audio sample rate.

```rust
pub fn rate(&self) -> u32
```

--------------------------------

### Initialize C History Module

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html?search=

Ensures that the C-side history module is initialized exactly once using a `Once` static. This is a common pattern for one-time setup in Rust.

```rust
use std::sync::Once;

static START: Once = Once::new();

START.call_once(|| unsafe { history_init_c() });
```

--------------------------------

### Histogram Initialization

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html?search=

Creates a new, empty histogram with 1000 bins, all initialized to zero. This is the starting point for accumulating energy measurements.

```rust
fn new() -> Self {
    Histogram(Box::new([0; 1000]))
}
```

--------------------------------

### TruePeak Initialization and Usage

Source: https://docs.rs/ebur128/latest/src/ebur128/true_peak.rs.html

Demonstrates how to create a TruePeak instance and use it to check for true peaks in audio data. This is useful for ensuring audio does not exceed digital clipping limits.

```rust
impl TruePeak {
    pub fn new(rate: u32, channels: u32) -> Option<Self> {
        UpsamplingScanner::new(rate, channels).map(|interp| Self { interp })
    }

    pub fn reset(&mut self) {
        self.interp.reset();
    }

    pub fn check_true_peak<'a, T: Sample + 'a, S: crate::Samples<'a, T>>(
        &mut self,
        src: S,
        peaks: &mut [f64],
    ) {
        self.interp.check_true_peak(src, peaks)
    }

    pub fn seed<'a, T: Sample + 'a, S: crate::Samples<'a, T>>(&mut self, src: S) {
        let mut true_peaks: SmallVec<[f64; 16]> = smallvec![0.0; src.channels()];
        self.interp.check_true_peak(src, &mut true_peaks)
    }
}
```

--------------------------------

### Get number of frames in Planar data

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html

Returns the total number of frames available in the Planar data, calculated as the difference between the end and start indices.

```rust
pub fn frames(&self) -> usize {
        self.end - self.start
    }
```

--------------------------------

### Get Gating Block Count and Energy

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html?search=

A convenience function to get the gating block count and energy for a single history entry by calling the multiple version with a slice containing only self.

```rust
pub fn gating_block_count_and_energy(&self) -> Result<(u64, f64), HistoryError> {
        Self::gating_block_count_and_energy_multiple(&[self])
    }
```

--------------------------------

### TruePeak Initialization and Usage

Source: https://docs.rs/ebur128/latest/src/ebur128/true_peak.rs.html?search=u32+-%3E+bool

Demonstrates how to create a TruePeak instance with a given sample rate and number of channels, and how to check for true peaks in audio data. The `seed` method is used to prime the interpolator.

```rust
pub struct TruePeak {
    /// Interpolator/resampler.
    interp: UpsamplingScanner,
}

impl TruePeak {
    pub fn new(rate: u32, channels: u32) -> Option<Self> {
        UpsamplingScanner::new(rate, channels).map(|interp| Self { interp })
    }

    pub fn reset(&mut self) {
        self.interp.reset();
    }

    pub fn check_true_peak<'a, T: Sample + 'a, S: crate::Samples<'a, T>>(
        &mut self,
        src: S,
        peaks: &mut [f64],
    ) {
        self.interp.check_true_peak(src, peaks)
    }

    pub fn seed<'a, T: Sample + 'a, S: crate::Samples<'a, T>>(&mut self, src: S) {
        let mut true_peaks: SmallVec<[f64; 16]> = smallvec![0.0; src.channels()];
        self.interp.check_true_peak(src, &mut true_peaks)
    }
}
```

--------------------------------

### Get Channel Map

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Retrieves the configured channel mapping.

```APIDOC
## channel_map

### Description
Gets the configured channel map.

### Method
`channel_map(&self) -> &[Channel]`

### Returns
A slice representing the channel map.
```

--------------------------------

### EbuR128 Initialization and Basic Measurements (f32)

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html

Demonstrates initializing EbuR128 for stereo audio with f32 sample data and performing basic loudness measurements after processing.

```rust
let mut data = vec![0.0f32; 48_000 * 5 * 2];
let mut accumulator = 0.0;
let step = 2.0 * std::f32::consts::PI * 440.0 / 48_000.0;
for out in data.chunks_exact_mut(2) {
    let val = f32::sin(accumulator);
    out[0] = val;
    out[1] = val;
    accumulator += step;
}

let mut ebu = EbuR128::new(2, 48_000, Mode::all()).unwrap();
ebu.add_frames_f32(&data).unwrap();

assert_float_eq!(
    ebu.loudness_global().unwrap(),
    -0.6500000000000054,
    abs <= 0.000001
);
```

--------------------------------

### C API: Create TruePeak instance

Source: https://docs.rs/ebur128/latest/src/ebur128/true_peak.rs.html?search=std%3A%3Avec

Creates a C-compatible TruePeak instance. Requires a sample rate and number of channels. Returns a raw pointer to the created instance.

```rust
#[cfg(feature = "c-tests")]
extern "C" {
    pub fn true_peak_create_c(rate: u32, channels: u32) -> *mut c_void;
}
```

--------------------------------

### Compare Rust and C Relative Threshold Implementations

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

This `quickcheck` test compares the `relative_threshold` calculation between the Rust implementation and its C-compatible counterpart. The snippet is truncated, showing only the setup phase.

```Rust
    #[quickcheck]
    fn compare_c_impl_relative_threshold(
        energy: Vec<Energy>,
        use_histogram: bool,
        max: NonZeroU16,
    ) -> Result<(), String> {
        init();

        let mut hist = History::new(use_histogram, max.get() as usize);
        for e in &energy {
            hist.add(e.0);
        }

        let val = hist.relative_threshold();

        let val_c = unsafe {
            let hist_c = history_create_c(i32::from(use_histogram), max.get() as usize);
            for e in &energy {
```

--------------------------------

### Get Mode

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Retrieves the configured operating mode of the Ebur128 instance.

```APIDOC
## mode

### Description
Gets the configured mode.

### Method
`mode(&self) -> Mode`

### Returns
The current `Mode` setting.
```

--------------------------------

### prev_sample_peak

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the maximum sample peak from the last call to add_frames.

```APIDOC
## prev_sample_peak

### Description
Retrieves the maximum sample peak value for a specified channel that occurred during the most recent call to `add_frames`. The value is typically converted to dBFS using the formula: 20 * log10(peak_value).

### Method
`get`

### Endpoint
`/peak/previous_sample/{channel_number}`

### Parameters
#### Path Parameters
- **channel_number** (u32) - Required - The index of the channel for which to retrieve the previous sample peak.

### Returns
- `f64`: The maximum sample peak from the last frame addition for the specified channel. Returns an error if the SAMPLE_PEAK mode is not enabled or the channel index is invalid.
```

--------------------------------

### Initialize C Test Environment with `Once`

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

This snippet provides an `init` function that uses `std::sync::Once` to ensure a C-side initialization function (`history_init_c`) is called exactly once, typically for setting up test fixtures.

```Rust
    fn init() {
        use std::sync::Once;

        static START: Once = Once::new();

        START.call_once(|| unsafe { history_init_c() });
    }
```

--------------------------------

### Sample trait implementation for i32

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html

Provides the `Sample` trait implementation for `i32`, defining its maximum amplitude based on `i32::MIN` and a raw conversion to `f64`.

```rust
impl Sample for i32 {
    const MAX_AMPLITUDE: f64 = -(Self::MIN as f64);

    #[inline(always)]
    fn as_f64_raw(self) -> f64 {
        self as f64
    }
}
```

--------------------------------

### Getting number of channels

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html?search=std%3A%3Avec

Returns the number of channels in the planar data.

```rust
#[inline]
    fn channels(&self) -> usize {
        self.data.len()
    }
```

--------------------------------

### Test Case: Comparing Rust and C Interpolation Implementations

Source: https://docs.rs/ebur128/latest/src/ebur128/interp.rs.html?search=

This test case compares the output of the Rust and C interpolation implementations using QuickCheck. It generates a signal, processes it with both implementations, and asserts that the results are approximately equal.

```rust
#[quickcheck]
    fn compare_c_impl(signal: Signal<f32>) -> quickcheck::TestResult {
        let frames = signal.data.len() / signal.channels as usize;
        let factor = if signal.rate < 96_000 {
            4
        } else if signal.rate < 192_000 {
            2
        } else {
            return quickcheck::TestResult::discard();
        };

        let mut data_out = vec![0.0f32; signal.data.len() * factor];
        let mut data_out_c = vec![0.0f32; signal.data.len() * factor];

        process_rust(
            &signal.data,
            &mut data_out,
            factor,
            signal.channels as usize,
        );

        unsafe {
            let interp = interp_create_c(49, factor as u32, signal.channels);
            interp_process_c(
                interp,
                frames,
                signal.data.as_ptr(),
                data_out_c.as_mut_ptr(),
            );
            interp_destroy_c(interp);
        }

        for (i, (r, c)) in data_out.iter().zip(data_out_c.iter()).enumerate() {
            assert_float_eq!(
                *r,
                *c,
                // For a performance-boost, filter is defined as f32, causing slightly lower precision
                abs <= 0.000004,
                "Rust and C implementation differ at sample {}",
                i
            );
        }

        quickcheck::TestResult::passed()
    }
```

--------------------------------

### Get Mode

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Retrieves the current operating mode of the loudness measurement.

```APIDOC
## mode

### Description
Get the configured mode.

### Method
`mode()`

### Returns
- `Mode`: The current operating mode.
```

--------------------------------

### Rust Test: Comparing C and Rust Implementations for i16

Source: https://docs.rs/ebur128/latest/src/ebur128/true_peak.rs.html?search=u32+-%3E+bool

This quickcheck test compares the results of the C implementation of true peak checking against the Rust implementation for i16 audio samples. It discards tests with very high sample rates to avoid excessive test duration.

```rust
#[quickcheck]
    fn compare_c_impl_i16(signal: Signal<i16>) -> quickcheck::TestResult {
        if signal.rate >= 192_000 {
            return quickcheck::TestResult::discard();
        }

        // Maximum of 400ms but our input is up to 5000ms, so distribute it evenly
        // by shrinking accordingly.
        let len = signal.data.len() / signal.channels as usize;
        let len = std::cmp::min(2 * len / 25, 4 * ((signal.rate as usize + 5) / 10));

        let mut peaks = vec![0.0f64; signal.channels as usize];
        let mut peaks_c = vec![0.0f64; signal.channels as usize];

        {
            let mut tp = TruePeak::new(signal.rate, signal.channels).unwrap();
            tp.check_true_peak(
                crate::Interleaved::new(
                    &signal.data[0..(len * signal.channels as usize)],
                    signal.channels as usize,
                )
                .unwrap(),
                &mut peaks,
            );
        }

    }
```

--------------------------------

### Verify Loudness Metrics with i32 Audio Data

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=u32+-%3E+bool

This snippet demonstrates how to process stereo i32 audio data and assert various loudness metrics, including global, momentary, short-term, windowed loudness, and loudness range. It also verifies sample and true peak values.

```rust
let mut data = vec![0i32; 48_000 * 5 * 2];
        let mut accumulator = 0.0;
        let step = 2.0 * std::f32::consts::PI * 440.0 / 48_000.0;
        for out in data.chunks_exact_mut(2) {
            let val = f32::sin(accumulator) * (i32::MAX - 1) as f32;
            out[0] = val as i32;
            out[1] = val as i32;
            accumulator += step;
        }

        let mut ebu = EbuR128::new(2, 48_000, Mode::all()).unwrap();
        ebu.add_frames_i32(&data).unwrap();

        assert_float_eq!(
            ebu.loudness_global().unwrap(),
            -0.6500000000000054,
            abs <= 0.000001
        );
        assert_float_eq!(
            ebu.loudness_momentary().unwrap(),
            -0.6813325598274425,
            abs <= 0.000001
        );
        assert_float_eq!(
            ebu.loudness_shortterm().unwrap(),
            -0.6827591715105212,
            abs <= 0.000001
        );
        assert_float_eq!(
            ebu.loudness_window(1).unwrap(),
            -0.8742956620040943,
            abs <= 0.000001
        );
        assert_float_eq!(ebu.loudness_range().unwrap(), 0.0, abs <= 0.000001);

        assert_float_eq!(ebu.sample_peak(0).unwrap(), 1.0, abs <= 0.000001);
        assert_float_eq!(ebu.sample_peak(1).unwrap(), 1.0, abs <= 0.000001);
        assert_float_eq!(ebu.prev_sample_peak(0).unwrap(), 1.0, abs <= 0.000001);
        assert_float_eq!(ebu.prev_sample_peak(1).unwrap(), 1.0, abs <= 0.000001);

        assert_float_eq!(
            ebu.true_peak(0).unwrap(),
            1.0008491277694702,
            abs <= 0.000001
        );
        assert_float_eq!(
            ebu.true_peak(1).unwrap(),
            1.0008491277694702,
            abs <= 0.000001
        );
        assert_float_eq!(
            ebu.prev_true_peak(0).unwrap(),
            1.0008491277694702,
            abs <= 0.000001
        );
        assert_float_eq!(
            ebu.prev_true_peak(1).unwrap(),
            1.0008491277694702,
            abs <= 0.000001
        );

        assert_float_eq!(
            ebu.relative_threshold().unwrap(),
            -10.650000000000006,
            abs <= 0.000001
        );
    }
```

--------------------------------

### Get Max History

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Retrieves the configured maximum history duration in milliseconds.

```APIDOC
## max_history

### Description
Gets the configured maximum history in milliseconds.

### Method
`max_history(&self) -> usize`

### Returns
The maximum history duration in milliseconds.
```

--------------------------------

### Initialize Ebur128 with Default Parameters

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=std%3A%3Avec

Creates a new Ebur128 instance with default settings for audio processing. This is the primary constructor for the library.

```rust
pub fn new(mode: Mode, rate: u32, channels: u32) -> Result<Self, Error> {
        let sample_peak = vec![0.0; channels as usize];
        let true_peak = vec![0.0; channels as usize];

        let history = usize::MAX;
        let samples_in_100ms = (rate as usize + 5) / 10;

        let window = if mode.contains(Mode::S) {
            3000
        } else if mode.contains(Mode::M) {
            400
        } else {
            return Err(Error::InvalidMode);
        };

        let audio_data = Self::allocate_audio_data(channels, rate, window)?;
        // start at the beginning of the buffer
        let audio_data_index = 0;

        let block_energy_history =
            crate::history::History::new(mode.contains(Mode::HISTOGRAM), history / 100);

        let short_term_block_energy_history =
            crate::history::History::new(mode.contains(Mode::HISTOGRAM), history / 3000);
        let short_term_frame_counter = 0;

        let filter = crate::filter::Filter::new(
            rate,
            channels,
            mode.contains(Mode::SAMPLE_PEAK),
            mode.contains(Mode::TRUE_PEAK),
        );

        let channel_map = default_channel_map(channels);

        // the first block needs 400ms of audio data
        let needed_frames = samples_in_100ms * 4;

        Ok(Self {
            mode,
            rate,
            channels,
            audio_data,
            audio_data_index,
            needed_frames,
            channel_map: channel_map.into_boxed_slice(),
            samples_in_100ms,
            filter,
            block_energy_history,
            short_term_block_energy_history,
            short_term_frame_counter,
            sample_peak: sample_peak.into_boxed_slice(),
            true_peak: true_peak.into_boxed_slice(),
            window,
            history,
        })
    }
```

--------------------------------

### Get Max Window

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Retrieves the configured maximum window duration in milliseconds.

```APIDOC
## max_window

### Description
Gets the configured maximum window duration in milliseconds.

### Method
`max_window(&self) -> usize`

### Returns
The maximum window duration in milliseconds.
```

--------------------------------

### true_peak

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the maximum true peak for a specific channel from all processed frames.

```APIDOC
## true_peak

### Description
Retrieves the maximum true peak value for a specified channel across all frames processed by the EBU R128 instance. The true peak is calculated using an implementation-defined algorithm (e.g., polyphase FIR interpolator) and converted to dBTP using the formula: 20 * log10(true_peak_value).

### Method
`get`

### Endpoint
`/peak/true/{channel_number}`

### Parameters
#### Path Parameters
- **channel_number** (u32) - Required - The index of the channel for which to retrieve the true peak.

### Returns
- `f64`: The maximum true peak for the specified channel. Returns an error if the TRUE_PEAK mode is not enabled or the channel index is invalid.
```

--------------------------------

### TruePeak::new

Source: https://docs.rs/ebur128/latest/src/ebur128/true_peak.rs.html?search=

Creates a new TruePeak instance. It initializes the internal UpsamplingScanner with the specified sample rate and number of channels.

```APIDOC
## Method TruePeak::new

### Description
Creates a new TruePeak instance. It initializes the internal UpsamplingScanner with the specified sample rate and number of channels.

### Signature
`pub fn new(rate: u32, channels: u32) -> Option<Self>`

### Parameters
* `rate` (u32) - The sample rate of the audio signal.
* `channels` (u32) - The number of audio channels.

### Returns
* `Option<Self>` - Returns `Some(TruePeak)` if initialization is successful, otherwise `None`.
```

--------------------------------

### sample_peak

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the maximum sample peak for a specific channel from all processed frames.

```APIDOC
## sample_peak

### Description
Retrieves the maximum sample peak value for a specified channel across all frames processed by the EBU R128 instance. The value is typically converted to dBFS using the formula: 20 * log10(peak_value).

### Method
`get`

### Endpoint
`/peak/sample/{channel_number}`

### Parameters
#### Path Parameters
- **channel_number** (u32) - Required - The index of the channel for which to retrieve the sample peak.

### Returns
- `f64`: The maximum sample peak for the specified channel. Returns an error if the SAMPLE_PEAK mode is not enabled or the channel index is invalid.
```

--------------------------------

### Compare Rust and C Gated Loudness Implementations

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

This `quickcheck` test compares the `gated_loudness` calculation between the Rust implementation and its C-compatible counterpart, asserting their floating-point equality within a small tolerance.

```Rust
    #[quickcheck]
    fn compare_c_impl_gated_loudness(
        energy: Vec<Energy>,
        use_histogram: bool,
        max: NonZeroU16,
    ) -> Result<(), String> {
        init();

        let mut hist = History::new(use_histogram, max.get() as usize);
        for e in &energy {
            hist.add(e.0);
        }

        let val = hist.gated_loudness();

        let val_c = unsafe {
            let hist_c = history_create_c(i32::from(use_histogram), max.get() as usize);
            for e in &energy {
                history_add_c(hist_c, e.0);
            }

            let val = history_gated_loudness_c(hist_c);
            history_destroy_c(hist_c);
            val
        };

        if !float_eq!(val, val_c, ulps <= 2) {
            Err(format!("{val} != {val_c}"))
        } else {
            Ok(())
        }
    }
```

--------------------------------

### Sample trait implementation for i16

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html

Provides the `Sample` trait implementation for `i16`, defining its maximum amplitude based on `i16::MIN` and a raw conversion to `f64`.

```rust
impl Sample for i16 {
    const MAX_AMPLITUDE: f64 = -(Self::MIN as f64);

    #[inline(always)]
    fn as_f64_raw(self) -> f64 {
        self as f64
    }
}
```

--------------------------------

### loudness_window

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the loudness of a specified window in LUFS. The window size is in seconds.

```APIDOC
## loudness_window

### Description
Calculates and returns the loudness for a specified time window in LUFS. The window size cannot exceed the maximum window size set for the instance.

### Method
`get`

### Endpoint
`/loudness/window/{window_seconds}`

### Parameters
#### Path Parameters
- **window_seconds** (u32) - Required - The duration of the window in seconds for which to calculate loudness.
```

--------------------------------

### Sample trait implementation for f64

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html

Provides the `Sample` trait implementation for `f64`, defining its maximum amplitude and a raw conversion to `f64`.

```rust
impl Sample for f64 {
    const MAX_AMPLITUDE: f64 = 1.0;

    #[inline(always)]
    fn as_f64_raw(self) -> f64 {
        self
    }
}
```

--------------------------------

### loudness_momentary

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the momentary loudness, which is the loudness of the last 400ms of audio, in LUFS.

```APIDOC
## loudness_momentary

### Description
Calculates and returns the momentary loudness of the audio processed so far, specifically the last 400 milliseconds, in LUFS.

### Method
`get`

### Endpoint
`/loudness/momentary`

### Returns
- `f64`: The momentary loudness in LUFS. Returns -infinity if the energy is non-positive.
```

--------------------------------

### loudness_global

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html

Gets the global integrated loudness in LUFS. Requires the 'I' mode to be enabled.

```APIDOC
## loudness_global

### Description
Gets the global integrated loudness in LUFS. Requires the 'I' mode to be enabled.

### Method
`pub fn loudness_global(&self) -> Result<f64, Error>`

### Response
#### Success Response (200)
* `f64`: The global integrated loudness in LUFS.
```

--------------------------------

### Sample trait implementation for f32

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html

Provides the `Sample` trait implementation for `f32`, defining its maximum amplitude and a raw conversion to `f64`.

```rust
impl Sample for f32 {
    const MAX_AMPLITUDE: f64 = 1.0;

    #[inline(always)]
    fn as_f64_raw(self) -> f64 {
        self as f64
    }
}
```

--------------------------------

### Get Channels

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Retrieves the number of audio channels the library is configured to process.

```APIDOC
## channels

### Description
Get the configured number of channels.

### Method
`channels()`

### Returns
- `u32`: The number of audio channels.
```

--------------------------------

### EbuR128 Configuration and Initialization

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=u32+-%3E+bool

This snippet shows the internal logic for allocating audio data and updating channel-specific parameters when the audio configuration changes. It ensures that internal buffers and settings are correctly adjusted based on the new channel count and sample rate.

```rust
self.audio_data = Self::allocate_audio_data(channels, rate, self.window)?;

        if self.channels != channels {
            self.channels = channels;
            self.channel_map = default_channel_map(channels).into_boxed_slice();
            self.sample_peak = vec![0.0; channels as usize].into_boxed_slice();
            self.true_peak = vec![0.0; channels as usize].into_boxed_slice();
        }

        if self.rate != rate {
            self.rate = rate;
            self.samples_in_100ms = (rate as usize + 5) / 10;
        }

        self.filter = crate::filter::Filter::new(
            rate,
            channels,
            self.mode.contains(Mode::SAMPLE_PEAK),
            self.mode.contains(Mode::TRUE_PEAK),
        );

        // the first block needs 400ms of audio data
        self.needed_frames = self.samples_in_100ms * 4;
        // start at the beginning of the buffer
        self.audio_data_index = 0;
        // reset short term frame counter
        self.short_term_frame_counter = 0;

        Ok(())
    }
```

--------------------------------

### Calculate Loudness Metrics for Planar i32 Audio

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=u32+-%3E+bool

This snippet shows how to generate a sine wave, process it using planar i32 data with EbuR128, and verify loudness measurements. It's similar to the i16 example but uses 32-bit integers for audio samples.

```rust
let mut data = vec![0i32; 48_000 * 5 * 2];
let mut accumulator = 0.0;
let step = 2.0 * std::f32::consts::PI * 440.0 / 48_000.0;
let (fst, snd) = data.split_at_mut(48_000 * 5);
for (fst, snd) in Iterator::zip(fst.iter_mut(), snd.iter_mut()) {
    let val = f32::sin(accumulator) * (i32::MAX - 1) as f32;
    *fst = val as i32;
    *snd = val as i32;
    accumulator += step;
}

let mut ebu = EbuR128::new(2, 48_000, Mode::all() & !Mode::HISTOGRAM).unwrap();
ebu.add_frames_planar_i32(&[fst, snd]).unwrap();

assert_float_eq!(
    ebu.loudness_global().unwrap(),
    -0.6826039914171368,
    abs <= 0.000001
);
assert_float_eq!(
    ebu.loudness_momentary().unwrap(),
    -0.6813325598274425,
    abs <= 0.000001
);
assert_float_eq!(
    ebu.loudness_shortterm().unwrap(),
    -0.6827591715105212,
    abs <= 0.000001
);
assert_float_eq!(
    ebu.loudness_window(1).unwrap(),
    -0.8742956620040943,
    abs <= 0.000001
);
assert_float_eq!(
    ebu.loudness_range().unwrap(),
    0.00006921150165073442,
    abs <= 0.000001
);

assert_float_eq!(ebu.sample_peak(0).unwrap(), 1.0, abs <= 0.000001);
assert_float_eq!(ebu.sample_peak(1).unwrap(), 1.0, abs <= 0.000001);
assert_float_eq!(ebu.prev_sample_peak(0).unwrap(), 1.0, abs <= 0.000001);
assert_float_eq!(ebu.prev_sample_peak(1).unwrap(), 1.0, abs <= 0.000001);

assert_float_eq!(
    ebu.true_peak(0).unwrap(),
    1.0008491277694702,
    abs <= 0.000001
);

```

--------------------------------

### Compare Rust and C Implementations of Gated Loudness

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html

A quickcheck test that compares the gated loudness calculation between the Rust implementation and its C counterpart. It initializes the C side, adds energy data to both, and asserts equality within a tolerance.

```rust
#[quickcheck]
fn compare_c_impl_gated_loudness(
    energy: Vec<Energy>,
    use_histogram: bool,
    max: NonZeroU16,
) -> Result<(), String> {
    init();

    let mut hist = History::new(use_histogram, max.get() as usize);
    for e in &energy {
        hist.add(e.0);
    }

    let val = hist.gated_loudness();

    let val_c = unsafe {
        let hist_c = history_create_c(i32::from(use_histogram), max.get() as usize);
        for e in &energy {
            history_add_c(hist_c, e.0);
        }

        let val = history_gated_loudness_c(hist_c);
        history_destroy_c(hist_c);
        val
    };

    if !float_eq!(val, val_c, ulps <= 2) {
        Err(format!("{val} != {val_c}"))
    } else {
        Ok(())
    }
}
```

--------------------------------

### Get Max History

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=std%3A%3Avec

Retrieves the maximum history duration in milliseconds configured for the library.

```APIDOC
## Get Max History

### Description
Retrieves the maximum history duration in milliseconds.

### Method
`GET`

### Endpoint
`/max_history`

### Response
#### Success Response (200)
- **history** (usize) - The maximum history duration in milliseconds.
```

--------------------------------

### Seeding Filter State with Audio Samples

Source: https://docs.rs/ebur128/latest/src/ebur128/filter.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Initializes the filter's state by processing a source of audio samples without producing output. This is useful for setting up the filter's internal state before starting actual loudness measurements. It iterates through channels and applies the filter's coefficients to the input samples.

```rust
pub fn seed<'a, T: Sample + 'a, S: crate::Samples<'a, T>>(
        &mut self,
        src: S,
        channel_map: &[crate::ebur128::Channel],
    ) {
        assert!(channel_map.len() == self.channels as usize);
        assert!(src.channels() == self.channels as usize);
        assert!(self.filter_state.len() == self.channels as usize);

        ftz::with_ftz(|ftz| {
            for (c, channel_map) in channel_map.iter().enumerate() {
                if *channel_map == crate::ebur128::Channel::Unused {
                    continue;
                }

                assert!(c < src.channels());

                let Filter {
                    ref mut filter_state,
                    ref a,
                    ..
                } = *self;
                let filter_state = &mut filter_state[c];

                src.foreach_sample(c, |src| {

```

--------------------------------

### Get Rate

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=std%3A%3Avec

Retrieves the audio sample rate (in Hz) the library is configured to process.

```APIDOC
## Get Rate

### Description
Retrieves the audio sample rate.

### Method
`GET`

### Endpoint
`/rate`

### Response
#### Success Response (200)
- **rate** (u32) - The sample rate in Hz.
```

--------------------------------

### Process Audio in Chunks and Verify Aggregated Loudness

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html

This snippet demonstrates how to process audio data in chunks and then verify that the aggregated loudness measurements (sample peak, true peak, and global loudness) match the results obtained by processing the entire audio data at once.

```rust
let mut data = vec![0.0f32; 48_000 * 3];
        let mut accumulator = 0.0;
        let step = 2.0 * std::f32::consts::PI * 440.0 / 48_000.0;
        for out in data.chunks_exact_mut(1) {
            let val = f32::sin(accumulator);
            out[0] = val;
            accumulator += step;
        }

        let mut ebu1 = EbuR128::new(1, 48_000, Mode::all() | Mode::HISTOGRAM).unwrap();
        ebu1.add_frames_f32(&data).unwrap();

        let mut ebu_chunks = Vec::new();
        for i in 0..3usize {
            let mut ebu_chunk = EbuR128::new(1, 48_000, Mode::all() | Mode::HISTOGRAM & !Mode::HISTOGRAM).unwrap();
            let start_index = std::cmp::max(i as isize * 48_000, 0) as usize;
            let stop_index = std::cmp::min(start_index + 48_000 + (48_00 * 3), data.len());
            if start_index > 0 {
                ebu_chunk
                    .seed_frames_f32(&data[start_index - 48_00..start_index])
                    .unwrap();
            }
            ebu_chunk
                .add_frames_f32(&data[start_index..stop_index])
                .unwrap();
            ebu_chunks.push(ebu_chunk);
        }

        assert_float_eq!(
            ebu1.sample_peak(0).unwrap(),
            f64_max(ebu_chunks.iter().map(|meter| meter.sample_peak(0).unwrap())).unwrap(),
            abs <= 0.000001
        );

        assert_float_eq!(
            ebu1.true_peak(0).unwrap(),
            f64_max(ebu_chunks.iter().map(|meter| meter.true_peak(0).unwrap())).unwrap(),
            abs <= 0.000001
        );

        assert_float_eq!(
            ebu1.loudness_global().unwrap(),
            EbuR128::loudness_global_multiple(ebu_chunks.iter()).unwrap(),
            abs <= 0.000001
        );
```

--------------------------------

### loudness_range_multiple

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the loudness range (LRA) of a program across multiple EbuR128 instances.

```APIDOC
## loudness_range_multiple

### Description
Calculates the Loudness Range (LRA) across multiple `EbuR128` instances, according to the EBU 3342 standard. This is useful for analyzing LRA over segments or different files.

### Method
`post`

### Endpoint
`/loudness/range/multiple`

### Request Body
- **instances** (array of EbuR128) - Required - An array of `EbuR128` instances to calculate the combined loudness range from.

### Returns
- `f64`: The loudness range in LU. Returns an error if LRA mode is not enabled for any instance.
```

--------------------------------

### loudness_shortterm

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the short-term loudness, which is the loudness of the last 3 seconds of audio, in LUFS.

```APIDOC
## loudness_shortterm

### Description
Calculates and returns the short-term loudness of the audio processed so far, specifically the last 3 seconds, in LUFS.

### Method
`get`

### Endpoint
`/loudness/shortterm`

### Returns
- `f64`: The short-term loudness in LUFS. Returns -infinity if the energy is non-positive.
```

--------------------------------

### Queue Implementation for Energy History

Source: https://docs.rs/ebur128/latest/src/ebur128/history.rs.html

A fixed-size queue to store recent audio energy measurements. Useful for calculating loudness ranges and dynamic thresholds.

```rust
pub struct Queue {
    queue: VecDeque<f64>,
    max: usize,
}

impl Queue {
    fn new(max: usize) -> Self {
        Queue {
            queue: VecDeque::with_capacity(std::cmp::min(max, 5000)),
            max,
        }
    }

    fn add(&mut self, energy: f64) {
        // Remove last element to keep the size
        if self.max == self.queue.len() {
            self.queue.pop_front();
        }
        self.queue.push_back(energy);
    }

    fn set_max_size(&mut self, max: usize) {
        if self.queue.len() < max {
            // FIXME: Use shrink() once stabilized
            self.queue.resize(max, 0.0);
            self.queue.shrink_to_fit();
        }
        self.max = max;
    }

    fn reset(&mut self) {
        self.queue.clear();
    }

    fn calc_relative_threshold(&self) -> (u64, f64) {
        (self.queue.len() as u64, self.queue.iter().sum::<f64>())
    }

    fn loudness_range(q: &[f64]) -> f64 {
        if q.is_empty() {
            return 0.0;
        }

        let power = q.iter().sum::<f64>() / q.len() as f64;
        let minus_twenty_decibels = f64::powf(10.0, -20.0 / 10.0);
        let integrated = minus_twenty_decibels * power;

        let relgated = q.iter().take_while(|&v| *v < integrated).count();
        let relgated_size = q.len() - relgated;

        if let Some(relgated_size) = relgated_size.checked_sub(1) {
            let relgated_size = relgated_size as f64;
            let h_en = q[relgated + (relgated_size * 0.95 + 0.5) as usize];
            let l_en = q[relgated + (relgated_size * 0.1 + 0.5) as usize];

            energy_to_loudness(h_en) - energy_to_loudness(l_en)
        } else {
            0.0
        }
    }
}

```

--------------------------------

### Get Sample Rate

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Retrieves the audio sample rate the library is configured to process.

```APIDOC
## rate

### Description
Get the configured sample rate.

### Method
`rate()`

### Returns
- `u32`: The sample rate in Hz.
```

--------------------------------

### QuickCheck Test for i16 Input with C Implementation Comparison

Source: https://docs.rs/ebur128/latest/src/ebur128/filter.rs.html?search=std%3A%3Avec

This test uses QuickCheck to generate random i16 audio signals and compares the results of the Rust implementation against the C implementation for processing.

```rust
#[quickcheck]
fn compare_c_impl_i16(
    signal: Signal<i16>,
    calculate_sample_peak: bool,
    calculate_true_peak: bool,
) {
    // Maximum of 400ms but our input is up to 5000ms, so distribute it evenly
    // by shrinking accordingly.
    let frames = signal.data.len() / signal.channels as usize;
    let frames = std::cmp::min(2 * frames / 25, 4 * ((signal.rate as usize + 5) / 10));

    let mut data_out = vec![0.0f64; frames * signal.channels as usize];
    let mut data_out_c = vec![0.0f64; frames * signal.channels as usize];

    let channel_map_c = vec![1; signal.channels as usize];
    let channel_map = vec![Channel::Left; signal.channels as usize];

    let (sp, tp) = {
        let mut f = Filter::new(
            signal.rate,
            signal.channels,
            calculate_sample_peak,
            calculate_true_peak,
        );

        let mut data_out_tmp = vec![0.0f64; frames * signal.channels as usize];

        f.process(
            crate::Interleaved::new(
                &signal.data[..(frames * signal.channels as usize)],
                signal.channels as usize,
            )
            .unwrap(),
            &mut data_out_tmp,
            0,
            &channel_map,
        );

        for (c, src) in data_out_tmp.chunks_exact(frames).enumerate() {
            for (i, src) in src.iter().enumerate() {
                data_out[i * signal.channels as usize + c] = *src;
            }
        }

        (Vec::from(f.sample_peak()), Vec::from(f.true_peak()))
    };
}
```

--------------------------------

### Initialize ebur128 with default parameters

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

This snippet shows the initialization of the ebur128 struct with default settings for audio processing. It allocates necessary buffers and sets up internal filters and history tracking based on the provided mode, channels, and sample rate.

```rust
let sample_peak = vec![0.0; channels as usize];
        let true_peak = vec![0.0; channels as usize];

        let history = usize::MAX;
        let samples_in_100ms = (rate as usize + 5) / 10;

        let window = if mode.contains(Mode::S) {
            3000
        } else if mode.contains(Mode::M) {
            400
        } else {
            return Err(Error::InvalidMode);
        };

        let audio_data = Self::allocate_audio_data(channels, rate, window)?;
        // start at the beginning of the buffer
        let audio_data_index = 0;

        let block_energy_history =
            crate::history::History::new(mode.contains(Mode::HISTOGRAM), history / 100);

        let short_term_block_energy_history =
            crate::history::History::new(mode.contains(Mode::HISTOGRAM), history / 3000);
        let short_term_frame_counter = 0;

        let filter = crate::filter::Filter::new(
            rate,
            channels,
            mode.contains(Mode::SAMPLE_PEAK),
            mode.contains(Mode::TRUE_PEAK),
        );

        let channel_map = default_channel_map(channels);

        // the first block needs 400ms of audio data
        let needed_frames = samples_in_100ms * 4;

        Ok(Self {
            mode,
            rate,
            channels,
            audio_data,
            audio_data_index,
            needed_frames,
            channel_map: channel_map.into_boxed_slice(),
            samples_in_100ms,
            filter,
            block_energy_history,
            short_term_block_energy_history,
            short_term_frame_counter,
            sample_peak: sample_peak.into_boxed_slice(),
            true_peak: true_peak.into_boxed_slice(),
            window,
            history,
        })
```

--------------------------------

### Get Configured Channel Map

Source: https://docs.rs/ebur128/latest/ebur128/struct.EbuR128.html?search=std%3A%3Avec

Retrieves the slice representing the configured channel types.

```rust
pub fn channel_map(&self) -> &[Channel]
```

--------------------------------

### EbuR128::new

Source: https://docs.rs/ebur128/latest/ebur128/struct.EbuR128.html?search=u32+-%3E+bool

Creates a new instance of the EbuR128 loudness analyzer with the specified configuration.

```APIDOC
## EbuR128::new

### Description
Create a new instance with the given configuration.

### Method
`new(channels: u32, rate: u32, mode: Mode) -> Result<Self, Error>`

### Parameters
* `channels` (u32) - The number of audio channels.
* `rate` (u32) - The sample rate of the audio.
* `mode` (Mode) - The loudness measurement mode.

### Returns
A `Result` containing a new `EbuR128` instance on success, or an `Error` on failure.
```

--------------------------------

### Get Max Window

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=std%3A%3Avec

Retrieves the maximum window duration in milliseconds configured for audio processing.

```APIDOC
## Get Max Window

### Description
Retrieves the maximum window duration in milliseconds.

### Method
`GET`

### Endpoint
`/max_window`

### Response
#### Success Response (200)
- **window** (usize) - The maximum window duration in milliseconds.
```

--------------------------------

### Get Mode

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=std%3A%3Avec

Retrieves the configured audio mode (e.g., standard, mixed, or true peak).

```APIDOC
## Get Mode

### Description
Retrieves the configured audio mode.

### Method
`GET`

### Endpoint
`/mode`

### Response
#### Success Response (200)
- **mode** (Mode) - The current audio mode configuration.
```

--------------------------------

### EbuR128::new

Source: https://docs.rs/ebur128/latest/ebur128/struct.EbuR128.html?search=

Creates a new instance of the EbuR128 loudness analyzer with the specified configuration.

```APIDOC
## EbuR128::new

### Description
Creates a new instance with the given configuration.

### Signature
`pub fn new(channels: u32, rate: u32, mode: Mode) -> Result<Self, Error>`

### Parameters
* `channels` (u32) - The number of audio channels.
* `rate` (u32) - The sample rate of the audio.
* `mode` (Mode) - The analysis mode to use.

### Returns
A `Result` containing a new `EbuR128` instance on success, or an `Error` on failure.
```

--------------------------------

### Sample trait implementations for f32 and f64

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html?search=std%3A%3Avec

Provides implementations for the Sample trait for f32 and f64 types, defining MAX_AMPLITUDE and a raw conversion to f64.

```rust
impl Sample for f32 {
    const MAX_AMPLITUDE: f64 = 1.0;

    #[inline(always)]
    fn as_f64_raw(self) -> f64 {
        self as f64
    }
}
impl Sample for f64 {
    const MAX_AMPLITUDE: f64 = 1.0;

    #[inline(always)]
    fn as_f64_raw(self) -> f64 {
        self
    }
}
```

--------------------------------

### Getting number of frames

Source: https://docs.rs/ebur128/latest/src/ebur128/utils.rs.html?search=std%3A%3Avec

Returns the total number of frames available in the planar data slice.

```rust
#[inline]
    fn frames(&self) -> usize {
        self.end - self.start
    }
```

--------------------------------

### loudness_range

Source: https://docs.rs/ebur128/latest/src/ebur128/ebur128.rs.html?search=

Get the loudness range (LRA) of the program in LU, calculated according to EBU 3342.

```APIDOC
## loudness_range

### Description
Calculates and returns the Loudness Range (LRA) of the audio program in LU, adhering to the EBU 3342 standard. This measurement requires the LRA mode to be enabled.

### Method
`get`

### Endpoint
`/loudness/range`

### Returns
- `f64`: The loudness range in LU. Returns an error if LRA mode is not enabled.
```