cubeb

https://docs.rs/cubeb/0.33.0
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This library provides Rust bindings for the cubeb C library, enabling interaction with system audio.
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### Cubeb StreamBuilder Example: Sine Wave Generation

Source: https://docs.rs/cubeb/0.33.0/src/cubeb/stream.rs_search=std%3A%3Avec

This example demonstrates the initialization of a Cubeb context and the setup of an audio stream using `StreamBuilder`. It configures parameters for a mono, 16-bit signed little-endian output stream and sets up a sine wave generation callback.

```rust
use cubeb::{Context, MonoFrame, Sample};
use std::f32::consts::PI;
use std::thread;
use std::time::Duration;

const SAMPLE_FREQUENCY: u32 = 48_000;
const STREAM_FORMAT: cubeb::SampleFormat = cubeb::SampleFormat::S16LE;
type Frame = MonoFrame<i16>;

let ctx = Context::init(None, None).unwrap();

let params = cubeb::StreamParamsBuilder::new()
    .format(STREAM_FORMAT)
    .rate(SAMPLE_FREQUENCY)
    .channels(1)
    .layout(cubeb::ChannelLayout::MONO)
    .prefs(cubeb::StreamPrefs::DUCKING)
    .take();

let freq = 440.0;
let mut phase = 0.0f32;
let phase_inc = freq / SAMPLE_FREQUENCY as f32;
let volume = 0.25;

let mut builder = cubeb::StreamBuilder::<Frame>::new();
builder
    .name("Cubeb Sine Wave")
    .output(&ctx, &params)
    .data_callback(move |_, output| {
        for x in output.iter_mut() {
            x.m = ( (phase * 2.0 * PI).sin() * volume * (i16::MAX as f32) ) as i16;
            phase = (phase + phase_inc) % 1.0;
        }
        output.len() as isize
    })
    .state_callback(|state| {
        println!("Stream state: {:?}", state);
    });
let stream = builder.init(&ctx).expect("Failed to initialize stream");

stream.start().unwrap();
thread::sleep(Duration::from_secs(1));
stream.stop().unwrap();

```

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

### Cubeb Stream Builder Example

Source: https://docs.rs/cubeb/0.33.0/src/cubeb/stream.rs_search=u32+-%3E+bool

Illustrates the initialization of a cubeb audio context and the setup of stream parameters using `StreamParamsBuilder`. This code snippet sets the sample format, rate, channels, and layout for an audio stream.

```rust
/// Stream builder
///
/// ```no_run
/// use cubeb::{Context, MonoFrame, Sample};
/// use std::f32::consts::PI;
/// use std::thread;
/// use std::time::Duration;
///
/// const SAMPLE_FREQUENCY: u32 = 48_000;
/// const STREAM_FORMAT: cubeb::SampleFormat = cubeb::SampleFormat::S16LE;
/// type Frame = MonoFrame<i16>;
///
/// let ctx = Context::init(None, None).unwrap();

```

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

### Control Audio Stream Playback in Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.StreamRef_search=std%3A%3Avec

Demonstrates how to start and stop an audio stream using the StreamRef. It includes a complete example of initializing a cubeb context, setting up stream parameters, defining a data callback to generate audio data, and then starting and stopping the stream playback.

```rust
pub fn start(&self) -> Result<(), Error>
pub fn stop(&self) -> Result<(), Error>
```

```rust
fn main() {
    let ctx = common::init("Cubeb tone example").expect("Failed to create cubeb context");

    let params = cubeb::StreamParamsBuilder::new()
        .format(STREAM_FORMAT)
        .rate(SAMPLE_FREQUENCY)
        .channels(1)
        .layout(cubeb::ChannelLayout::MONO)
        .take();

    let mut position = 0u32;

    let mut builder = cubeb::StreamBuilder::<Frame>::new();
    builder
        .name("Cubeb tone (mono)")
        .default_output(&params)
        .latency(0x1000)
        .data_callback(move |_, output| {
            // generate our test tone on the fly
            for f in output.iter_mut() {
                // North American dial tone
                let t1 = (2.0 * PI * 350.0 * position as f32 / SAMPLE_FREQUENCY as f32).sin();
                let t2 = (2.0 * PI * 440.0 * position as f32 / SAMPLE_FREQUENCY as f32).sin();

                f.m = i16::from_float(0.5 * (t1 + t2));

                position += 1;
            }
            output.len() as isize
        })
        .state_callback(|state| {
            println!("stream {:?}", state);
        });

    let stream = builder.init(&ctx).expect("Failed to create cubeb stream");

    stream.start().unwrap();
    thread::sleep(Duration::from_millis(500));
    stream.stop().unwrap();
}
```

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

### Start Audio Stream Playback (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.StreamRef_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Initiates playback for an audio stream. This function returns a Result, indicating success or an Error if the stream fails to start. The example demonstrates starting a tone generation stream.

```rust
pub fn start(&self) -> Result<(), Error>
```

```rust
57    stream.start().unwrap();
```

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

### Stream Creation and Playback Example

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Stream_search=

This example demonstrates how to initialize a Cubeb stream, configure its parameters, generate audio data (a square wave in this case), and control playback.

```APIDOC
## Stream<F>

### Description
Represents an audio input/output stream.

### Methods

#### `as_ptr(&self) -> *mut cubeb_stream`

Returns a raw pointer to the underlying `cubeb_stream`.

### Example
```rust
extern crate cubeb;
use std::thread;
use std::time::Duration;

type Frame = cubeb::MonoFrame<f32>;

fn main() {
    let ctx = cubeb::init("Cubeb tone example").unwrap();

    let params = cubeb::StreamParamsBuilder::new()
        .format(cubeb::SampleFormat::Float32LE)
        .rate(44_100)
        .channels(1)
        .layout(cubeb::ChannelLayout::MONO)
        .prefs(cubeb::StreamPrefs::NONE)
        .take();

    let phase_inc = 440.0 / 44_100.0;
    let mut phase = 0.0;
    let volume = 0.25;

    let mut builder = cubeb::StreamBuilder::<Frame>::new();
    builder
        .name("Cubeb Square Wave")
        .default_output(&params)
        .latency(0x1000)
        .data_callback(move |_, output| {
            // Generate a square wave
            for x in output.iter_mut() {
                x.m = if phase < 0.5 { volume } else { -volume };
                phase = (phase + phase_inc) % 1.0;
            }

            output.len() as isize
        })
        .state_callback(|state| {
            println!("stream {:?}", state);
        });
    let stream = builder.init(&ctx).expect("Failed to create stream.");

    // Start playback
    stream.start().unwrap();

    // Play for 1/2 second
    thread::sleep(Duration::from_millis(500));

    // Shutdown
    stream.stop().unwrap();
}
```
```

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

### Example: Checking Device Capabilities with DeviceFormat (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceFormat_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates how to use the `contains()` method of `DeviceFormat` to check for specific audio sample formats supported by a device. This example iterates through available formats and prints them, along with other device information.

```rust
fn print_device_info(info: &cubeb::DeviceInfo) {
    let devtype = if info.device_type().contains(DeviceType::INPUT) {
        "input"
    } else if info.device_type().contains(DeviceType::OUTPUT) {
        "output"
    } else {
        "unknown?"
    };

    let devstate = match info.state() {
        cubeb::DeviceState::Disabled => "disabled",
        cubeb::DeviceState::Unplugged => "unplugged",
        cubeb::DeviceState::Enabled => "enabled",
    };

    let devdeffmt = match info.default_format() {
        DeviceFormat::S16LE => "S16LE",
        DeviceFormat::S16BE => "S16BE",
        DeviceFormat::F32LE => "F32LE",
        DeviceFormat::F32BE => "F32BE",
        _ => "unknown?",
    };

    let mut devfmts = "".to_string();
    if info.format().contains(DeviceFormat::S16LE) {
        devfmts = format!("{} S16LE", devfmts);
    }
    if info.format().contains(DeviceFormat::S16BE) {
        devfmts = format!("{} S16BE", devfmts);
    }
    if info.format().contains(DeviceFormat::F32LE) {
        devfmts = format!("{} F32LE", devfmts);
    }
    if info.format().contains(DeviceFormat::F32BE) {
        devfmts = format!("{} F32BE", devfmts);
    }

    if let Some(device_id) = info.device_id() {
        let preferred = if info.preferred().is_empty() {
            ""
        } else {
            " (PREFERRED)"
        };
        println!("dev: \"{{}}\"{{}}", device_id, preferred);
    }
    if let Some(friendly_name) = info.friendly_name() {
        println!("\tName:    \"{{}}\"", friendly_name);
    }
    if let Some(group_id) = info.group_id() {
        println!("\tGroup:   \"{{}}\"", group_id);
    }
    if let Some(vendor_name) = info.vendor_name() {
        println!("\tVendor:  \"{{}}\"", vendor_name);
    }
    println!("\tType:    {{}}", devtype);
    println!("\tState:   {{}}", devstate);
    println!("\tCh:      {{}}", info.max_channels());
    println!(
        "\tFormat:  {{}} (0x{{:x}}) (default: {{}})",
        &devfmts[1..],
        info.format(),
        devdeffmt
    );
    println!(
        "\tRate:    {{}} - {{}} (default: {{}})",
        info.min_rate(),
        info.max_rate(),
        info.default_rate()
    );
    println!(
        "\tLatency: lo {{}} frames, hi {{}} frames",
        info.latency_lo(),
        info.latency_hi()
    );
}
```

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

### Stream Example

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Stream_search=std%3A%3Avec

An example demonstrating the creation and playback of a simple audio tone using the cubeb Stream API.

```APIDOC
## §Example
```rust
extern crate cubeb;
use std::thread;
use std::time::Duration;

type Frame = cubeb::MonoFrame<f32>;

fn main() {
    let ctx = cubeb::init("Cubeb tone example").unwrap();

    let params = cubeb::StreamParamsBuilder::new()
        .format(cubeb::SampleFormat::Float32LE)
        .rate(44_100)
        .channels(1)
        .layout(cubeb::ChannelLayout::MONO)
        .prefs(cubeb::StreamPrefs::NONE)
        .take();

    let phase_inc = 440.0 / 44_100.0;
    let mut phase = 0.0;
    let volume = 0.25;

    let mut builder = cubeb::StreamBuilder::<Frame>::new();
    builder
        .name("Cubeb Square Wave")
        .default_output(&params)
        .latency(0x1000)
        .data_callback(move |_, output| {
            // Generate a square wave
            for x in output.iter_mut() {
                x.m = if phase < 0.5 { volume } else { -volume };
                phase = (phase + phase_inc) % 1.0;
            }

            output.len() as isize
        })
        .state_callback(|state| {
            println!("stream {:?}", state);
        });
    let stream = builder.init(&ctx).expect("Failed to create stream.");

    // Start playback
    stream.start().unwrap();

    // Play for 1/2 second
    thread::sleep(Duration::from_millis(500));

    // Shutdown
    stream.stop().unwrap();
}
```
```

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

### Print Device Information (Example)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceInfo

An example function demonstrating how to iterate through and print various properties of a cubeb::DeviceInfo object. It showcases how to interpret device types, states, formats, and other attributes.

```rust
fn print_device_info(info: &cubeb::DeviceInfo) {
    let devtype = if info.device_type().contains(DeviceType::INPUT) {
        "input"
    } else if info.device_type().contains(DeviceType::OUTPUT) {
        "output"
    } else {
        "unknown?"
    };

    let devstate = match info.state() {
        cubeb::DeviceState::Disabled => "disabled",
        cubeb::DeviceState::Unplugged => "unplugged",
        cubeb::DeviceState::Enabled => "enabled",
    };

    let devdeffmt = match info.default_format() {
        DeviceFormat::S16LE => "S16LE",
        DeviceFormat::S16BE => "S16BE",
        DeviceFormat::F32LE => "F32LE",
        DeviceFormat::F32BE => "F32BE",
        _ => "unknown?",
    };

    let mut devfmts = "".to_string();
    if info.format().contains(DeviceFormat::S16LE) {
        devfmts = format!("{} S16LE", devfmts);
    }
    if info.format().contains(DeviceFormat::S16BE) {
        devfmts = format!("{} S16BE", devfmts);
    }
    if info.format().contains(DeviceFormat::F32LE) {
        devfmts = format!("{} F32LE", devfmts);
    }
    if info.format().contains(DeviceFormat::F32BE) {
        devfmts = format!("{} F32BE", devfmts);
    }

    if let Some(device_id) = info.device_id() {
        let preferred = if info.preferred().is_empty() {
            ""
        } else {
            " (PREFERRED)"
        };
        println!("dev: \"{}\" {}{}", device_id, preferred);
    }
    if let Some(friendly_name) = info.friendly_name() {
        println!("\tName:    \"{}\"", friendly_name);
    }
    if let Some(group_id) = info.group_id() {
        println!("\tGroup:   \"{}\"", group_id);
    }
    if let Some(vendor_name) = info.vendor_name() {
        println!("\tVendor:  \"{}\"", vendor_name);
    }
    println!("\tType:    {}", devtype);
    println!("\tState:   {}", devstate);
    println!("\tCh:      {}", info.max_channels());
    println!(
        "\tFormat:  {} (0x{:x}) (default: {})",
        &devfmts[1..],
        info.format(),
        devdeffmt
    );
    println!(
        "\tRate:    {} - {} (default: {})",
        info.min_rate(),
        info.max_rate(),
        info.default_rate()
    );
    println!(
        "\tLatency: lo {} frames, hi {} frames",
        info.latency_lo(),
        info.latency_hi()
    );
}
```

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

### Example: Print Audio Device Information in Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceInfo_search=u32+-%3E+bool

This example demonstrates how to iterate through audio devices and print detailed information for each. It utilizes various methods of the `DeviceInfo` struct to display device type, state, supported formats, rates, latency, and identifiers.

```rust
15fn print_device_info(info: &cubeb::DeviceInfo) {
16    let devtype = if info.device_type().contains(DeviceType::INPUT) {
17        "input"
18    } else if info.device_type().contains(DeviceType::OUTPUT) {
19        "output"
20    } else {
21        "unknown?"
22    };
23
24    let devstate = match info.state() {
25        cubeb::DeviceState::Disabled => "disabled",
26        cubeb::DeviceState::Unplugged => "unplugged",
27        cubeb::DeviceState::Enabled => "enabled",
28    };
29
30    let devdeffmt = match info.default_format() {
31        DeviceFormat::S16LE => "S16LE",
32        DeviceFormat::S16BE => "S16BE",
33        DeviceFormat::F32LE => "F32LE",
34        DeviceFormat::F32BE => "F32BE",
35        _ => "unknown?",
36    };
37
38    let mut devfmts = "".to_string();
39    if info.format().contains(DeviceFormat::S16LE) {
40        devfmts = format!("{} S16LE", devfmts);
41    }
42    if info.format().contains(DeviceFormat::S16BE) {
43        devfmts = format!("{} S16BE", devfmts);
44    }
45    if info.format().contains(DeviceFormat::F32LE) {
46        devfmts = format!("{} F32LE", devfmts);
47    }
48    if info.format().contains(DeviceFormat::F32BE) {
49        devfmts = format!("{} F32BE", devfmts);
50    }
51
52    if let Some(device_id) = info.device_id() {
53        let preferred = if info.preferred().is_empty() {
54            ""
55        } else {
56            " (PREFERRED)"
57        };
58        println!("dev: \"{}\"", device_id, preferred);
59    }
60    if let Some(friendly_name) = info.friendly_name() {
61        println!("\tName:    \"{}\"", friendly_name);
62    }
63    if let Some(group_id) = info.group_id() {
64        println!("\tGroup:   \"{}\"", group_id);
65    }
66    if let Some(vendor_name) = info.vendor_name() {
67        println!("\tVendor:  \"{}\"", vendor_name);
68    }
69    println!("\tType:    {}", devtype);
70    println!("\tState:   {}", devstate);
71    println!("\tCh:      {}", info.max_channels());
72    println!(
73        "\tFormat:  {} (0x{{:x}}) (default: {{}})",
74        &devfmts[1..],
75        info.format(),
76        devdeffmt
77    );
78    println!(
79        "\tRate:    {} - {} (default: {{}}))",
80        info.min_rate(),
81        info.max_rate(),
82        info.default_rate()
83    );
84    println!(
85        "\tLatency: lo {} frames, hi {} frames",
86        info.latency_lo(),
87        info.latency_hi()
88    );
89}

```

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

### Stream Start API

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Stream_search=u32+-%3E+bool

Starts audio playback for the stream.

```APIDOC
## pub fn start(&self) -> Result<(), Error>

### Description
Start playback.

### Method
GET

### Endpoint
N/A (Method on Stream object)

### Parameters
None

### Request Body
None

### Response
#### Success Response (200)
`()`

#### Response Example
None (Success is unit type)

### Error Handling
Returns `Err` if playback cannot be started.
```

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

### Enable Rustdoc Example Scraping with Cargo

Source: https://docs.rs/cubeb/0.33.0/scrape-examples-help

Shows the command to enable Rustdoc's unstable feature for scraping examples. This command analyzes documented crates and includes source code snippets of item usages in the generated documentation.

```bash
cargo doc -Zunstable-options -Zrustdoc-scrape-examples
```

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

### Create and Play Audio Stream with Dial Tone

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Stream

Demonstrates creating an audio stream and generating a North American dial tone. It configures the stream and uses a data callback to synthesize the two frequencies that constitute the dial tone. The example includes starting and stopping the stream after a brief delay.

```rust
fn main() {
    let ctx = common::init("Cubeb tone example").expect("Failed to create cubeb context");

    let params = cubeb::StreamParamsBuilder::new()
        .format(STREAM_FORMAT)
        .rate(SAMPLE_FREQUENCY)
        .channels(1)
        .layout(cubeb::ChannelLayout::MONO)
        .take();

    let mut position = 0u32;

    let mut builder = cubeb::StreamBuilder::<Frame>::new();
    builder
        .name("Cubeb tone (mono)")
        .default_output(&params)
        .latency(0x1000)
        .data_callback(move |_, output| {
            // generate our test tone on the fly
            for f in output.iter_mut() {
                // North American dial tone
                let t1 = (2.0 * PI * 350.0 * position as f32 / SAMPLE_FREQUENCY as f32).sin();
                let t2 = (2.0 * PI * 440.0 * position as f32 / SAMPLE_FREQUENCY as f32).sin();

                f.m = i16::from_float(0.5 * (t1 + t2));

                position += 1;
            }
            output.len() as isize
        })
        .state_callback(|state| {
            println!("stream {:?}", state);
        });

    let stream = builder.init(&ctx).expect("Failed to create cubeb stream");

    stream.start().unwrap();
    thread::sleep(Duration::from_millis(500));
    stream.stop().unwrap();
}
```

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

### Start Cubeb Stream

Source: https://docs.rs/cubeb/0.33.0/cubeb/ffi/fn.cubeb_stream_start_search=std%3A%3Avec

Starts an audio stream using the cubeb library. This function is part of the cubeb::ffi module.

```APIDOC
## cubeb_stream_start

### Description
Starts an audio stream.

### Method
`unsafe extern "C"`

### Endpoint
N/A (C function)

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
*   **stream** (*mut cubeb_stream*) - Required - A pointer to the cubeb_stream structure to start.

### Request Example
N/A (C function signature)

### Response
#### Success Response (0)
Returns 0 on success.

#### Error Response (-1)
Returns -1 on failure.

#### Response Example
`0` (on success)
`-1` (on failure)
```

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

### cubeb_audio_dump_start

Source: https://docs.rs/cubeb/0.33.0/cubeb/ffi/fn.cubeb_audio_dump_start_search=std%3A%3Avec

Starts an audio dump session. This function is marked as unsafe, indicating that it requires careful handling by the caller.

```APIDOC
## cubeb_audio_dump_start

### Description
Starts an audio dump session using the provided session pointer.

### Method
```
pub unsafe extern "C" fn cubeb_audio_dump_start(
    session: *mut cubeb_audio_dump_session,
) -> i32
```

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
- **session** (*mut cubeb_audio_dump_session) - Required - A mutable pointer to a `cubeb_audio_dump_session` structure that will be used to manage the audio dump.

### Request Example
This function does not have a request body in the typical HTTP sense. It operates on a C-style pointer passed directly.

### Response
#### Success Response (0)
Returns `0` on success.

#### Error Response (Non-zero)
Returns a non-zero value on failure. The specific error codes are not detailed in this documentation.

#### Response Example
```
0 // Success
-1 // Failure (example)
```
```

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

### Print Formatted Device Information in Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceInfo_search=

An example function demonstrating how to print detailed information about a cubeb::DeviceInfo object. It includes device type, state, supported formats, ID, name, vendor, and latency. This code snippet is extracted from the repository's examples.

```rust
15fn print_device_info(info: &cubeb::DeviceInfo) {
16    let devtype = if info.device_type().contains(DeviceType::INPUT) {
17        "input"
18    } else if info.device_type().contains(DeviceType::OUTPUT) {
19        "output"
20    } else {
21        "unknown?"
22    };
23
24    let devstate = match info.state() {
25        cubeb::DeviceState::Disabled => "disabled",
26        cubeb::DeviceState::Unplugged => "unplugged",
27        cubeb::DeviceState::Enabled => "enabled",
28    };
29
30    let devdeffmt = match info.default_format() {
31        DeviceFormat::S16LE => "S16LE",
32        DeviceFormat::S16BE => "S16BE",
33        DeviceFormat::F32LE => "F32LE",
34        DeviceFormat::F32BE => "F32BE",
35        _ => "unknown?",
36    };
37
38    let mut devfmts = "".to_string();
39    if info.format().contains(DeviceFormat::S16LE) {
40        devfmts = format!("{} S16LE", devfmts);
41    }
42    if info.format().contains(DeviceFormat::S16BE) {
43        devfmts = format!("{} S16BE", devfmts);
44    }
45    if info.format().contains(DeviceFormat::F32LE) {
46        devfmts = format!("{} F32LE", devfmts);
47    }
48    if info.format().contains(DeviceFormat::F32BE) {
49        devfmts = format!("{} F32BE", devfmts);
50    }
51
52    if let Some(device_id) = info.device_id() {
53        let preferred = if info.preferred().is_empty() {
54            ""
55        } else {
56            " (PREFERRED)"
57        };
58        println!("dev: \"{}\"", device_id, preferred);
59    }
60    if let Some(friendly_name) = info.friendly_name() {
61        println!("\tName:    \"{}\"", friendly_name);
62    }
63    if let Some(group_id) = info.group_id() {
64        println!("\tGroup:   \"{}\"", group_id);
65    }
66    if let Some(vendor_name) = info.vendor_name() {
67        println!("\tVendor:  \"{}\"", vendor_name);
68    }
69    println!("\tType:    ", devtype);
70    println!("\tState:   ", devstate);
71    println!("\tCh:      ", info.max_channels());
72    println!(
73        "\tFormat:  {} (0x{:x}) (default: )",
74        &devfmts[1..],
75        info.format(),
76        devdeffmt
77    );
78    println!(
79        "\tRate:    {} - {} (default: )",
80        info.min_rate(),
81        info.max_rate(),
82        info.default_rate()
83    );
84    println!(
85        "\tLatency: lo {} frames, hi {} frames",
86        info.latency_lo(),
87        info.latency_hi()
88    );
89}
```

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

### Example cubeb Initialization Helper

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Context

A helper function to initialize a cubeb context, demonstrating how to handle environment variables for backend selection and string conversion. It also includes logic for checking if the requested backend matches the one provided by cubeb.

```Rust
pub fn init<T: Into<Vec<u8>>>(ctx_name: T) -> Result<Context> {
    let backend = match env::var("CUBEB_BACKEND") {
        Ok(s) => Some(s),
        Err(_) => None,
    };

    let ctx_name = CString::new(ctx_name).unwrap();
    let ctx = Context::init(Some(ctx_name.as_c_str()), None);
    if let Ok(ref ctx) = ctx {
        if let Some(ref backend) = backend {
            let ctx_backend = ctx.backend_id();
            if backend != ctx_backend {
                let stderr = io::stderr();
                let mut handle = stderr.lock();

                writeln!(
                    handle,
                    "Requested backend `{{}}', got `{}`",
                    backend, ctx_backend
                )
                .unwrap();
            }
        }
    }

    ctx
}
```

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

### libcubeb Bindings for Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/index_search=u32+-%3E+bool

This library contains bindings to the cubeb C library which is used to interact with system audio. The library itself is a work in progress and is likely lacking documentation and test. The cubeb-rs library exposes the user API of libcubeb. It doesn’t expose the internal interfaces, so isn’t suitable for extending libcubeb. See cubeb-pulse-rs for an example of extending libcubeb via implementing a cubeb backend in rust. To get started, have a look at the `StreamBuilder`.

```APIDOC
## Crate cubeb

### Description
This library contains bindings to the cubeb C library which is used to interact with system audio. The library itself is a work in progress and is likely lacking documentation and test.
The cubeb-rs library exposes the user API of libcubeb. It doesn’t expose the internal interfaces, so isn’t suitable for extending libcubeb. See cubeb-pulse-rs for an example of extending libcubeb via implementing a cubeb backend in rust.
To get started, have a look at the `StreamBuilder`.

### Modules
- `ffi`

### Structs
- **ChannelLayout**: Some common layout definitions
- **Context**
- **ContextRef**
- **Device**
- **DeviceCollection**
- **DeviceCollectionRef**
- **DeviceFormat**: Architecture specific sample type.
- **DeviceInfo**
- **DeviceInfoRef**
- **DeviceRef**
- **DeviceType**: Whether a particular device is an input device (e.g. a microphone), or an output device (e.g. headphones).
- **MonoFrame**: A monaural frame.
- **StereoFrame**: A stereo frame.
- **Stream**: Audio input/output stream
- **StreamBuilder**: Stream builder
- **StreamCallbacks**
- **StreamParams**
- **StreamParamsBuilder**
- **StreamParamsRef**
- **StreamPrefs**: Miscellaneous stream preferences.
- **StreamRef

### Enums
- **DeviceState**: The state of a device.
- **Error**: An enumeration of possible errors that can happen when working with cubeb.
- **LogLevel**: Level (verbosity) of logging for a particular cubeb context.
- **SampleFormat**
- **State**: Stream states signaled via `state_callback`.

### Traits
- **Frame**: A `Frame` is a collection of samples which have a a specific layout represented by `ChannelLayout`
- **Sample**: An extension trait which allows the implementation of converting void* buffers from libcubeb-sys into rust slices of the appropriate type.

### Functions
- **init**: Initialize a new cubeb `Context`

### Type Aliases
- **DataCallback**: User supplied data callback.
- **DeviceChangedCallback**: User supplied callback called when the underlying device changed.
- **DeviceId**: An opaque handle used to refer to a particular input or output device across calls.
- **Result**
- **StateCallback**: User supplied state callback.
```

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

### Example: Enumerate Input and Output Devices in Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.ContextRef_search=

Shows how to initialize a cubeb context and then enumerate both input and output audio devices. It handles the `NotSupported` error for device enumeration and prints the number of found devices.

```rust
91fn main() {
    let ctx = common::init("Cubeb audio test").expect("Failed to create cubeb context");

    println!("Enumerating input devices for backend {}", ctx.backend_id());

    let devices = match ctx.enumerate_devices(DeviceType::INPUT) {
        Ok(devices) => devices,
        Err(cubeb::Error::NotSupported) => {
            println!("Device enumeration not support for this backend.");
            return;
        }
        Err(e) => {
            println!("Error enumerating devices: {}", e);
            return;
        }
    };

    println!("Found {} input devices", devices.len());
    for d in devices.iter() {
        print_device_info(d);
    }

    println!(
        "Enumerating output devices for backend "
    );

    let devices = match ctx.enumerate_devices(DeviceType::OUTPUT) {
        Ok(devices) => devices,
        Err(e) => {
            println!("Error enumerating devices: {}", e);
            return;
        }
    };

    println!("Found {} output devices", devices.len());
    for d in devices.iter() {
        print_device_info(d);
    }
}

```

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

### Cubeb Initialization API

Source: https://docs.rs/cubeb/0.33.0/cubeb/index

This section describes the process of initializing a new cubeb context, which is the entry point for interacting with the system audio.

```APIDOC
## init

### Description
Initializes a new cubeb `Context`.

### Method
GET

### Endpoint
/init

### Parameters
#### Query Parameters
- **log_level** (LogLevel) - Optional - Specifies the verbosity level for logging within the cubeb context.

### Response
#### Success Response (200)
- **context** (ContextRef) - A reference to the newly created cubeb context.

#### Response Example
{
  "context": "<opaque_context_handle>"
}
```

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

### Get Element or Subslice by Index (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceCollectionRef_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

The `get` method allows accessing elements or subslices using various index types. It returns `Some` with the requested item if the index is valid, and `None` otherwise. Examples demonstrate accessing single elements and ranges.

```rust
pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output>
where I: SliceIndex<[T]>

// Examples:
let v = [10, 40, 30];
assert_eq!(Some(&40), v.get(1));
assert_eq!(Some(&[10, 40][..]), v.get(0..2));
assert_eq!(None, v.get(3));
assert_eq!(None, v.get(0..4));
```

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

### Example: Initialize Cubeb Context and Backend ID (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.ContextRef

Demonstrates initializing a cubeb context with a given name and optionally checking if the requested backend matches the one provided by cubeb. It also shows how to retrieve and print the backend ID.

```rust
6pub fn init<T: Into<Vec<u8>>>(ctx_name: T) -> Result<Context> {
    let backend = match env::var("CUBEB_BACKEND") {
        Ok(s) => Some(s),
        Err(_) => None,
    };

    let ctx_name = CString::new(ctx_name).unwrap();
    let ctx = Context::init(Some(ctx_name.as_c_str()), None);
    if let Ok(ref ctx) = ctx {
        if let Some(ref backend) = backend {
            let ctx_backend = ctx.backend_id();
            if backend != ctx_backend {
                let stderr = io::stderr();
                let mut handle = stderr.lock();

                writeln!(
                    handle,
                    "Requested backend `{}', got `{}'",
                    backend, ctx_backend
                )
                .unwrap();
            }
        }
    }

    ctx
}
```

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

### Get Slice Length (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceCollectionRef_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

The `len` method returns the number of elements in a slice, which is a fundamental operation for collections. An example is provided demonstrating its usage.

```rust
pub fn len(&self) -> usize

// Example:
let a = [1, 2, 3];
assert_eq!(a.len(), 3);
```

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

### Example Device Enumeration and Output

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Context

Demonstrates how to enumerate input and output audio devices using a cubeb context and print their information. It includes error handling for unsupported device enumeration.

```Rust
fn main() {
    let ctx = common::init("Cubeb audio test").expect("Failed to create cubeb context");

    println!("Enumerating input devices for backend {}", ctx.backend_id());

    let devices = match ctx.enumerate_devices(DeviceType::INPUT) {
        Ok(devices) => devices,
        Err(cubeb::Error::NotSupported) => {
            println!("Device enumeration not support for this backend.");
            return;
        }
        Err(e) => {
            println!("Error enumerating devices: {}", e);
            return;
        }
    };

    println!("Found {} input devices", devices.len());
    for d in devices.iter() {
        print_device_info(d);
    }

    println!(
        "Enumerating output devices for backend {}",
        ctx.backend_id()
    );

    let devices = match ctx.enumerate_devices(DeviceType::OUTPUT) {
        Ok(devices) => devices,
        Err(e) => {
            println!("Error enumerating devices: {}", e);
            return;
        }
    };

    println!("Found {} output devices", devices.len());
    for d in devices.iter() {
        print_device_info(d);
    }
}
```

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

### Get Metadata of Path with Error Handling in Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/type.Result_search=

Shows how to get file metadata using `Path::metadata()` and handle potential errors using `and_then`. This example illustrates a common pattern for interacting with the file system where operations can fail due to non-existent paths or permission issues.

```rust
use std::{io::ErrorKind, path::Path};

// Note: on Windows "/" maps to "C:\"
let root_modified_time = Path::new("/").metadata().and_then(|md| md.modified());
assert!(root_modified_time.is_ok());

let should_fail = Path::new("/bad/path").metadata().and_then(|md| md.modified());
assert!(should_fail.is_err());
assert_eq!(should_fail.unwrap_err().kind(), ErrorKind::NotFound);
```

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

### Example: Print Audio Device Information in Rust

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceInfo_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Demonstrates how to use the `DeviceInfo` methods to print detailed information about an audio device. It covers device type, state, supported formats, rates, latency, and identifiers.

```rust
fn print_device_info(info: &cubeb::DeviceInfo) {
    let devtype = if info.device_type().contains(DeviceType::INPUT) {
        "input"
    } else if info.device_type().contains(DeviceType::OUTPUT) {
        "output"
    } else {
        "unknown?"
    };

    let devstate = match info.state() {
        cubeb::DeviceState::Disabled => "disabled",
        cubeb::DeviceState::Unplugged => "unplugged",
        cubeb::DeviceState::Enabled => "enabled",
    };

    let devdeffmt = match info.default_format() {
        DeviceFormat::S16LE => "S16LE",
        DeviceFormat::S16BE => "S16BE",
        DeviceFormat::F32LE => "F32LE",
        DeviceFormat::F32BE => "F32BE",
        _ => "unknown?",
    };

    let mut devfmts = "".to_string();
    if info.format().contains(DeviceFormat::S16LE) {
        devfmts = format!("{} S16LE", devfmts);
    }
    if info.format().contains(DeviceFormat::S16BE) {
        devfmts = format!("{} S16BE", devfmts);
    }
    if info.format().contains(DeviceFormat::F32LE) {
        devfmts = format!("{} F32LE", devfmts);
    }
    if info.format().contains(DeviceFormat::F32BE) {
        devfmts = format!("{} F32BE", devfmts);
    }

    if let Some(device_id) = info.device_id() {
        let preferred = if info.preferred().is_empty() {
            ""
        } else {
            " (PREFERRED)"
        };
        println!("dev: \"{}\"", device_id, preferred);
    }
    if let Some(friendly_name) = info.friendly_name() {
        println!("\tName:    \"{}\"", friendly_name);
    }
    if let Some(group_id) = info.group_id() {
        println!("\tGroup:   \"{}\"", group_id);
    }
    if let Some(vendor_name) = info.vendor_name() {
        println!("\tVendor:  \"{}\"", vendor_name);
    }
    println!("\tType:    {}", devtype);
    println!("\tState:   {}", devstate);
    println!("\tCh:      {}", info.max_channels());
    println!(
        "\tFormat:  {} (0x{{:x}}) (default: {})",
        &devfmts[1..],
        info.format(),
        devdeffmt
    );
    println!(
        "\tRate:    {} - {} (default: {})",
        info.min_rate(),
        info.max_rate(),
        info.default_rate()
    );
    println!(
        "\tLatency: lo {} frames, hi {} frames",
        info.latency_lo(),
        info.latency_hi()
    );
}
```

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

### Get First Slice Element (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceCollectionRef_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

The `first` method retrieves a reference to the first element of a slice. It returns `Some(&T)` if the slice is not empty, and `None` if it is empty. Examples show both scenarios.

```rust
pub fn first(&self) -> Option<&T>

// Examples:
let v = [10, 40, 30];
assert_eq!(Some(&10), v.first());

let w: &[i32] = &[];
assert_eq!(None, w.first());
```

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

### Get Last Slice Element (Rust)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceCollectionRef_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

The `last` method returns a reference to the last element of a slice. It returns `Some(&T)` for non-empty slices and `None` for empty slices. Examples cover both outcomes.

```rust
pub fn last(&self) -> Option<&T>

// Examples:
let v = [10, 40, 30];
assert_eq!(Some(&30), v.last());

let w: &[i32] = &[];
assert_eq!(None, w.last());
```

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

### Initialize Cubeb Context

Source: https://docs.rs/cubeb/0.33.0/cubeb/index_search=

Initializes a new cubeb context, which is the entry point for interacting with the audio system.

```APIDOC
## POST /cubeb/init

### Description
Initializes a new cubeb `Context`.

### Method
POST

### Endpoint
/cubeb/init

### Parameters
#### Query Parameters
- **log_level** (LogLevel) - Optional - The verbosity level for logging.

#### Request Body
This endpoint does not require a request body.

### Response
#### Success Response (200)
- **context_id** (string) - An opaque handle representing the initialized cubeb context.

#### Response Example
```json
{
  "context_id": "cubeb_context_12345"
}
```
```

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

### Rust: Get Cubeb Backend ID

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.Context_search=

Retrieves the backend identifier string for an initialized Cubeb context. This is useful for debugging or verifying which audio backend is currently in use. The example demonstrates its usage after context initialization.

```rust
6pub fn init<T: Into<Vec<u8>>>(ctx_name: T) -> Result<Context> {
    let backend = match env::var("CUBEB_BACKEND") {
        Ok(s) => Some(s),
        Err(_) => None,
    };

    let ctx_name = CString::new(ctx_name).unwrap();
    let ctx = Context::init(Some(ctx_name.as_c_str()), None);
    if let Ok(ref ctx) = ctx {
        if let Some(ref backend) = backend {
            let ctx_backend = ctx.backend_id();
            if backend != ctx_backend {
                let stderr = io::stderr();
                let mut handle = stderr.lock();

                writeln!(
                    handle,
                    "Requested backend `{}', got `{}'",
                    backend, ctx_backend
                )
                .unwrap();
            }
        }
    }

    ctx
}
```

```rust
91fn main() {
92    let ctx = common::init("Cubeb audio test").expect("Failed to create cubeb context");
93
94    println!("Enumerating input devices for backend {}", ctx.backend_id());
95
96    let devices = match ctx.enumerate_devices(DeviceType::INPUT) {
97        Ok(devices) => devices,
98        Err(cubeb::Error::NotSupported) => {
99            println!("Device enumeration not support for this backend.");
100            return;
101        }
102        Err(e) => {
103            println!("Error enumerating devices: {}", e);
104            return;
105        }
106    };
107
108    println!("Found {} input devices", devices.len());
109    for d in devices.iter() {
110        print_device_info(d);
111    }
112
113    println!(
114        "Enumerating output devices for backend "
115        ,
116        ctx.backend_id()
117    );
118
119    let devices = match ctx.enumerate_devices(DeviceType::OUTPUT) {
120        Ok(devices) => devices,
121        Err(e) => {
122            println!("Error enumerating devices: {}", e);
123            return;
124        }
125    };
126
127    println!("Found {} output devices", devices.len());
128    for d in devices.iter() {
129        print_device_info(d);
130    }
131}
```

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

### Get Element Index from Reference - Rust (Nightly)

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.DeviceCollectionRef_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Returns the index of an element reference within a slice. This method uses pointer arithmetic and does not compare elements. It returns `None` if the reference is not aligned with the start of an element. This is an experimental API.

```rust
#![feature(substr_range)]
pub fn element_offset(&self, element: &T) -> Option<usize>
{
    // Implementation details omitted for brevity
    // Example usage:
    // let nums: &[u32] = &[1, 7, 1, 1];
    // let num = &nums[2];
    // assert_eq!(nums.element_offset(num), Some(2));
    unimplemented!()
}
```

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

### ChannelLayout Constructors and Utility Methods

Source: https://docs.rs/cubeb/0.33.0/cubeb/struct.ChannelLayout_search=Option%3CT%3E%2C+%28T+-%3E+U%29+-%3E+Option%3CU%3E

Documentation for methods to create and check ChannelLayout instances.

```APIDOC
## ChannelLayout Constructors and Utility Methods

### Description
Methods for creating and checking ChannelLayout instances.

### Methods
* `empty() -> ChannelLayout`: Returns an empty set of flags.
* `all() -> ChannelLayout`: Returns the set containing all flags.
* `bits(&self) -> u32`: Returns the raw value of the flags currently stored.
* `from_bits(bits: u32) -> Option<ChannelLayout>`: Convert from underlying bit representation, unless that representation contains bits that do not correspond to a flag.
* `from_bits_truncate(bits: u32) -> ChannelLayout`: Convert from underlying bit representation, dropping any bits that do not correspond to flags.
* `from_bits_unchecked(bits: u32) -> ChannelLayout`: Convert from underlying bit representation, preserving all bits (even those not corresponding to a defined flag). This method is unsafe and requires the caller to ensure bit validity.
* `is_empty(&self) -> bool`: Returns `true` if no flags are currently stored.
* `is_all(&self) -> bool`: Returns `true` if all flags are currently set.
```
Tokens:
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