Audio Codec

https://docs.rs/audio-codec/0.3.30
Admin
Audio Codec is a Rust library providing encoders and decoders for multiple audio codec formats...
Tokens:39,641
Snippets:303
Trust Score:9.7
Update:5 months ago
Show doc for...
Tokens:
Raw
### Create New G722Encoder Instance

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Encoder.html

Instantiates a new G722Encoder with default settings. No specific setup is required beyond calling this function.

```rust
pub fn new() -> Self
```

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

### Create New G729Encoder Instance

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g729/struct.G729Encoder.html

Instantiates a new G.729 encoder. No setup or imports are required beyond having the struct available.

```rust
pub fn new() -> Self>
```

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

### Get Audio Channels

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/pcma.rs.html

Returns the number of audio channels supported by the codec. This implementation supports 1 channel.

```rust
fn channels(&self) -> u16 {
        1
    }
```

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

### Get fmtp for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the fmtp (format parameters) string for codecs that support them, such as Opus and TelephoneEvent. Returns `None` for codecs without specific parameters.

```rust
    pub fn fmtp(&self) -> Option<&str> {
        match self {
            CodecType::PCMU => None,
            CodecType::PCMA => None,
            CodecType::G722 => None,
            CodecType::G729 => None,
            #[cfg(feature = "opus")]
            CodecType::Opus => Some("minptime=10;useinbandfec=1"),
            CodecType::TelephoneEvent => Some("0-16"),
        }
    }
```

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

### G729Encoder - Get Channels

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g729/struct.G729Encoder.html

Retrieves the number of audio channels expected for input samples.

```APIDOC
## GET /audio_codec/g729/channels

### Description
Get the number of channels expected for input.

### Method
GET

### Endpoint
/audio_codec/g729/channels

### Response
#### Success Response (200)
- **channels** (u16) - The number of expected audio channels.

#### Response Example
```json
{
  "channels": 1
}
```
```

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

### Decoder Trait Implementation for PcmaDecoder

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcma/struct.PcmaDecoder.html

Provides methods for decoding audio data, getting sample rate, and getting channel count.

```APIDOC
## impl Decoder for PcmaDecoder

### decode

#### Description
Decode encoded audio data into PCM samples.

#### Method
`fn decode(&mut self, samples: &[u8]) -> PcmBuf`

### sample_rate

#### Description
Get the sample rate of the decoded audio.

#### Method
`fn sample_rate(&self) -> u32`

### channels

#### Description
Get the number of channels.

#### Method
`fn channels(&self) -> u16`
```

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

### Get Default PcmaDecoder Instance

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcma/struct.PcmaDecoder.html

Provides a default instance of PcmaDecoder. This is useful when a default value is needed.

```rust
fn default() -> PcmaDecoder
```

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

### Get Audio Sample Rate

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/pcma.rs.html

Returns the sample rate of the audio codec. This implementation is fixed at 8000 Hz.

```rust
fn sample_rate(&self) -> u32 {
        8000
    }
```

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

### G729Encoder - Get Sample Rate

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g729/struct.G729Encoder.html

Retrieves the expected sample rate for input audio samples.

```APIDOC
## GET /audio_codec/g729/sample_rate

### Description
Get the sample rate expected for input samples.

### Method
GET

### Endpoint
/audio_codec/g729/sample_rate

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

#### Response Example
```json
{
  "sample_rate": 8000
}
```
```

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

### Get Samplerate for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the sample rate (in Hz) at which the codec operates. Note that G722 has a higher sample rate than some other codecs.

```rust
    pub fn samplerate(&self) -> u32 {
        match self {
            CodecType::PCMU => 8000,
            CodecType::PCMA => 8000,
            CodecType::G722 => 16000,
            CodecType::G729 => 8000,
            #[cfg(feature = "opus")]
            CodecType::Opus => 48000,
            CodecType::TelephoneEvent => 8000,
        }
    }
```

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

### Get Decoded Audio Sample Rate

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/trait.Decoder.html

The sample_rate method returns the sample rate of the audio that the decoder will produce. This is crucial for correctly interpreting the decoded PCM samples.

```rust
fn sample_rate(&self) -> u32;
```

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

### Get MIME Type for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the MIME type string associated with each `CodecType`. This is useful for network protocols and file formats.

```rust
impl CodecType {
    pub fn mime_type(&self) -> &str {
        match self {
            CodecType::PCMU => "audio/PCMU",
            CodecType::PCMA => "audio/PCMA",
            CodecType::G722 => "audio/G722",
            CodecType::G729 => "audio/G729",
            #[cfg(feature = "opus")]
            CodecType::Opus => "audio/opus",
            CodecType::TelephoneEvent => "audio/telephone-event",
        }
    }
}
```

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

### Get G722Encoder Sample Rate

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Encoder.html

Retrieves the expected sample rate for input PCM samples for the G722Encoder. This indicates the expected frequency of the audio data.

```rust
fn sample_rate(&self) -> u32
```

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

### Get Number of Audio Channels

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/trait.Decoder.html

The channels method returns the number of audio channels present in the decoded output. This is important for applications that need to handle mono, stereo, or multi-channel audio.

```rust
fn channels(&self) -> u16;
```

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

### Get Channels for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the number of audio channels supported by the `CodecType`. Opus supports stereo (2 channels), while others typically support mono (1 channel).

```rust
    pub fn channels(&self) -> u16 {
        match self {
            #[cfg(feature = "opus")]
            CodecType::Opus => 2,
            _ => 1,
        }
    }
```

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

### Initialize G722Decoder with Custom Options

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Decoder.html

Creates a new instance of G722Decoder with specified options for bitrate, packing, and sample rate.

```rust
pub fn with_options(rate: Bitrate, packed: bool, eight_k: bool) -> Self
```

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

### Initialize G722Encoder with default options

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Creates a new G.722 encoder using the default bitrate (1.64000) and no special options.

```rust
pub fn new() -> Self {
        Self::with_options(Bitrate::Mode1_64000, false, false)
    }
```

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

### Initialize G722Encoder with custom options

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Creates a G.722 encoder with specified bitrate, sample rate (8kHz or 16kHz), and packing mode.

```rust
pub fn with_options(rate: Bitrate, eight_k: bool, packed: bool) -> Self {
        let mut encoder = Self {
            packed,
            eight_k,
            bits_per_sample: rate.bits_per_sample(),
            x: [0; 24],
            band: [G722Band::default(), G722Band::default()],
            out_buffer: 0,
            out_bits: 0,
        };

        // Initialize band states with correct starting values
        encoder.band[0].log_scale_factor = 32 << 2; // Initial det value for lower band
        encoder.band[1].log_scale_factor = 8 << 2; // Initial det value for upper band

        encoder
    }
```

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

### G729Decoder Initialization

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g729/struct.G729Decoder.html

Provides information on how to create a new instance of the G729Decoder.

```APIDOC
## POST /api/g729decoder/new

### Description
Create a new G.729 decoder instance.

### Method
POST

### Endpoint
/api/g729decoder/new

### Parameters
None

### Request Body
None

### Request Example
None

### Response
#### Success Response (200)
- **G729Decoder** (object) - A new instance of the G729Decoder.

#### Response Example
```json
{
  "decoder_instance_id": "unique_decoder_id"
}
```
```

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

### PcmaDecoder::new()

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcma/struct.PcmaDecoder.html

Creates a new instance of the PcmaDecoder.

```APIDOC
## PcmaDecoder::new()

### Description
Creates a new PcmaDecoder instance.

### Method
`pub fn new() -> Self`
```

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

### Create G722Encoder with Options

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Encoder.html

Creates a G722Encoder instance with specified bitrate, and options for 8kHz sample rate and packing. Ensure the provided Bitrate is compatible.

```rust
pub fn with_options(rate: Bitrate, eight_k: bool, packed: bool) -> Self
```

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

### Get Default PcmuDecoder Value

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcmu/struct.PcmuDecoder.html

Returns the default value for PcmuDecoder, useful for initialization when no specific configuration is needed.

```rust
fn default() -> PcmuDecoder
```

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

### Initialize Resampler with Custom Rates

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/resampler.rs.html

Creates a new `Resampler` instance. Configures filter parameters based on input and output rates. Ensure `output_rate` is not zero to avoid division by zero.

```rust
pub fn new(input_rate: usize, output_rate: usize) -> Self {
        let ratio = output_rate as f64 / input_rate as f64;
        let num_phases = 128;
        let taps_per_phase = 16; // Increased to 16 for SIMD alignment (4x f32)
        let filter_len = num_phases * taps_per_phase;

        let mut raw_coeffs = vec![0.0f32; filter_len];
        let cutoff = if ratio < 1.0 {
            ratio as f32 * 0.45
        } else {
            0.45f32
        };

        let center = (taps_per_phase as f32 - 1.0) / 2.0;

        for p in 0..num_phases {
            let mut sum = 0.0;
            let mut phase_coeffs = vec![0.0f32; taps_per_phase];
            for t in 0..taps_per_phase {
                let x = t as f32 - center - (p as f32 / num_phases as f32);
                let val = if x.abs() < 1e-6 {
                    2.0 * cutoff
                } else {
                    let x_pi = x * PI;
                    (x_pi * 2.0 * cutoff).sin() / x_pi
                };
                let window = 0.54
                    - 0.46
                        * (2.0 * PI * (t as f32 * num_phases as f32 + p as f32) 
                            / (filter_len as f32 - 1.0)) 
                            .cos();
                phase_coeffs[t] = val * window;
                sum += phase_coeffs[t];
            }
            for t in 0..taps_per_phase {
                raw_coeffs[p * taps_per_phase + t] = phase_coeffs[t] / sum;
            }
        }

        Self {
            input_rate,
            output_rate,
            ratio,
            coeffs: raw_coeffs,
            num_phases,
            taps_per_phase,
            history: vec![0.0; taps_per_phase],
            current_pos: 0.0,
        }
    }
```

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

### Define PcmaDecoder Struct

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcma/struct.PcmaDecoder.html

Defines the structure for the A-law (PCMA) decoder. No specific setup is required to use this struct.

```rust
pub struct PcmaDecoder {}
```

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

### Initialize Resampler

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/resampler/struct.Resampler.html

Creates a new Resampler instance. Specify the input and output sample rates.

```rust
pub fn new(input_rate: usize, output_rate: usize) -> Self
```

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

### G729Encoder - Create New Instance

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g729/struct.G729Encoder.html

Instantiates a new G.729 audio encoder.

```APIDOC
## POST /audio_codec/g729/new

### Description
Creates a new G.729 encoder instance.

### Method
POST

### Endpoint
/audio_codec/g729/new

### Request Body
None

### Response
#### Success Response (200)
- **G729Encoder** (object) - A new instance of the G729Encoder.

#### Response Example
```json
{
  "encoder_instance": "<opaque_encoder_object>"
}
```
```

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

### Get Clock Rate for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the clock rate (in Hz) for each `CodecType`. This is the number of samples per second the codec operates on.

```rust
    pub fn clock_rate(&self) -> u32 {
        match self {
            CodecType::PCMU => 8000,
            CodecType::PCMA => 8000,
            CodecType::G722 => 8000,
            CodecType::G729 => 8000,
            #[cfg(feature = "opus")]
            CodecType::Opus => 48000,
            CodecType::TelephoneEvent => 8000,
        }
    }
```

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

### PcmaEncoder::new()

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcma/struct.PcmaEncoder.html

Constructor for creating a new instance of PcmaEncoder.

```APIDOC
## PcmaEncoder::new()

### Description
Creates a new PcmaEncoder instance.

### Method
`pub fn new() -> Self`
```

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

### OpusDecoder Initialization

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/opus/struct.OpusDecoder.html

Provides methods for creating new instances of the OpusDecoder.

```APIDOC
## OpusDecoder::new

### Description
Create a new Opus decoder instance with specified sample rate and channels.

### Method
`pub fn new(sample_rate: u32, channels: u16) -> Self`

### Parameters
#### Path Parameters
- None

#### Query Parameters
- None

#### Request Body
- None

### Request Example
```rust
let decoder = OpusDecoder::new(48000, 2);
```

### Response
#### Success Response (200)
- **Self** (OpusDecoder) - A new OpusDecoder instance.

#### Response Example
```rust
// OpusDecoder instance
```

## OpusDecoder::new_default

### Description
Create a default Opus decoder with a sample rate of 48kHz and stereo channels.

### Method
`pub fn new_default() -> Self`

### Parameters
#### Path Parameters
- None

#### Query Parameters
- None

#### Request Body
- None

### Request Example
```rust
let decoder = OpusDecoder::new_default();
```

### Response
#### Success Response (200)
- **Self** (OpusDecoder) - A new default OpusDecoder instance.

#### Response Example
```rust
// OpusDecoder instance
```
```

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

### G.722 Decoder Constructor (With Options)

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Creates a new G.722 decoder instance with specified options for bitrate, packing, and 8kHz mode.

```rust
pub fn with_options(rate: Bitrate, packed: bool, eight_k: bool) -> Self {
    Self {
        packed,
        eight_k,
        bits_per_sample: rate.bits_per_sample(),
        x: Default::default(),
        band: Default::default(),
        in_buffer: 0,
        in_bits: 0,
    }
}
```

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

### Create Opus Encoder

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/opus.rs.html

Initializes a new Opus encoder with specified sample rate and channel count. Panics if the encoder creation fails.

```rust
pub fn new(sample_rate: u32, channel_count: u16) -> Self {
        let mut error = 0i32;
        let ptr = opus_encoder_create(
            sample_rate,
            channel_count,
            &mut error,
        );

        if error != OPUS_OK as i32 {
            panic!(
                "Failed to create Opus encoder: {}",
                opus_error_message(error)
            );
        }

        let encoder = NonNull::new(ptr).unwrap_or_else(|| {
            panic!("Failed to create Opus encoder: null pointer returned");
        });

        Self {
            encoder,
            sample_rate,
            channels: if channel_count == 1 { 1 } else { 2 },
        }
    }
```

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

### Get Payload Type for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the dynamic payload type number assigned to each `CodecType`. These are typically used in RTP packet headers.

```rust
    pub fn payload_type(&self) -> u8 {
        match self {
            CodecType::PCMU => 0,
            CodecType::PCMA => 8,
            CodecType::G722 => 9,
            CodecType::G729 => 18,
            #[cfg(feature = "opus")]
            CodecType::Opus => 111,
            CodecType::TelephoneEvent => 101,
        }
    }
```

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

### Get Type ID of a Generic Type T

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Encoder.html

Obtains the `TypeId` of a given type `T`. This is part of the `Any` trait implementation and is useful for runtime type identification.

```rust
fn type_id(&self) -> TypeId
```

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

### Get G722Encoder Channel Count

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Encoder.html

Retrieves the number of audio channels the G722Encoder expects for input samples. This is typically 1 for mono or 2 for stereo.

```rust
fn channels(&self) -> u16
```

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

### impl<T> CloneToUninit for T

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/enum.CodecType.html

An experimental nightly-only API for cloning a value into uninitialized memory. Use with caution as it is unsafe.

```rust
unsafe fn clone_to_uninit(&self, dest: *mut u8)
```

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

### Sample to Bytes Conversion

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Utilities for converting slices of `Sample` to `Vec<u8>`, considering the target system's endianness.

```APIDOC
## `samples_to_bytes(samples: &[Sample]) -> Vec<u8>`

Converts a slice of `Sample` (audio samples) into a byte vector.

### Behavior based on endianness:

- **Little-endian**: Directly reinterprets the memory of the `Sample` slice as bytes.
- **Big-endian**: Converts each `Sample` to its little-endian byte representation and collects them.
```

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

### Declare PcmuDecoder Struct

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcmu/struct.PcmuDecoder.html

Defines the PcmuDecoder struct, used for decoding μ-law (PCMU) audio format. No specific setup is required beyond this declaration.

```rust
pub struct PcmuDecoder {}
```

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

### G722Encoder Constructors

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Encoder.html

Provides information on how to create new instances of the G722Encoder.

```APIDOC
## G722Encoder Constructors

### `new()`

Creates a new `G722Encoder` with default options.

### `with_options(rate: Bitrate, eight_k: bool, packed: bool)`

Creates an encoder with specified bitrate and options.

- **rate** (Bitrate): The desired bitrate for encoding.
- **eight_k** (bool): If true, uses an 8kHz sampling rate.
- **packed** (bool): If true, the output will be packed.
```

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

### G.722 Decoder - Initialization

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Constructs a new G.722 decoder instance with default or specified options.

```APIDOC
## G.722 Decoder - Initialization

### Description
Initializes a new G.722 decoder. It can be created with default settings or customized using `with_options`.

### Method
`new()` or `with_options(rate: Bitrate, packed: bool, eight_k: bool)`

### Endpoint
N/A

### Parameters
- **rate** (Bitrate) - The desired bitrate for the decoder (e.g., `Bitrate::Mode1_64000`).
- **packed** (bool) - Flag indicating if the input bitstream is packed.
- **eight_k** (bool) - Flag indicating if the decoder should operate in an 8kHz mode.

### Request Example
```rust
let decoder = G722Decoder::new();
let decoder_custom = G722Decoder::with_options(Bitrate::Mode1_56000, true, false);
```

### Response
- **Self** (G722Decoder) - An instance of the G.722 decoder.

### Response Example
N/A
```

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

### Get RTP Map for Codec

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Returns the RTP map string for each `CodecType`. This is used in RTP (Real-time Transport Protocol) sessions to define codec parameters.

```rust
    pub fn rtpmap(&self) -> &str {
        match self {
            CodecType::PCMU => "PCMU/8000",
            CodecType::PCMA => "PCMA/8000",
            CodecType::G722 => "G722/8000",
            CodecType::G729 => "G729/8000",
            #[cfg(feature = "opus")]
            CodecType::Opus => "opus/48000/2",
            CodecType::TelephoneEvent => "telephone-event/8000",
        }
    }
```

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

### CodecType::fmtp Implementation

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/enum.CodecType.html

Returns an optional format parameter string for each CodecType variant. This is used for advanced configuration in RTP.

```rust
pub fn fmtp(&self) -> Option<&str>
```

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

### G.722 Decode Frame Logic

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Handles the decoding of G.722 encoded data, differentiating between 8kHz and 16kHz sample rates. Requires setup of the encoder/decoder instance.

```rust
let mut output = Vec::with_capacity(data.len() * 2);
        let mut idx = 0;

        if self.eight_k {
            while idx < data.len() {
                let code = self.extract_code(data, &mut idx);
                let (wd1, _, wd2) = self.parse_code(code);
                let rlow = self.process_low_band(wd1, wd2);
                output.push((rlow << 1) as i16);
            }
        } else {
            while idx < data.len() {
                let code = self.extract_code(data, &mut idx);
                let (wd1, ihigh, wd2) = self.parse_code(code);
                let rlow = self.process_low_band(wd1, wd2);
                let rhigh = self.process_high_band(ihigh);
                let pcm = self.apply_qmf_synthesis(rlow, rhigh);
                output.extend_from_slice(&pcm);
            }
        }
        output
```

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

### Decoder Trait Definition

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Defines the `Decoder` trait for audio decoding. Implementors must provide methods for decoding data, getting the sample rate, and the number of channels.

```rust
pub trait Decoder: Send + Sync {
    /// Decode encoded audio data into PCM samples
    fn decode(&mut self, data: &[u8]) -> PcmBuf;

    /// Get the sample rate of the decoded audio
    fn sample_rate(&self) -> u32;

    /// Get the number of channels
    fn channels(&self) -> u16;
}
```

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

### G722Decoder Methods

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/g722/struct.G722Decoder.html

Provides methods for creating and using the G722Decoder, including decoding audio frames.

```APIDOC
## Implementations

### impl G722Decoder

#### pub fn new() -> Self
Creates a new G722Decoder with default settings.

#### pub fn with_options(rate: Bitrate, packed: bool, eight_k: bool) -> Self
Creates a new G722Decoder with specified options.
- **rate** (Bitrate): The desired audio sample rate.
- **packed** (bool): Whether the input data is packed.
- **eight_k** (bool): Whether to use the 8kHz variant.

#### pub fn decode_frame(&mut self, data: &[u8]) -> PcmBuf
Decodes a G.722 frame and returns PCM samples. This is the main decoding function that processes G.722 encoded data.
- **data** (&[u8]): A slice of bytes containing the G.722 encoded frame.
- Returns: A `PcmBuf` containing the decoded PCM samples.
```

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

### Opus Encoder Creation

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/opus.rs.html

Initializes a new Opus encoder instance with specified sample rate, channels, and application type. Panics on creation failure.

```rust
pub fn new(sample_rate: u32, channels: u16) -> Self {
    let channel_count: c_int = if channels == 1 { 1 } else { 2 };
    let mut error: c_int = 0;
    let ptr = unsafe {
        opus_encoder_create(
            sample_rate as c_int,
            channel_count,
            OPUS_APPLICATION_VOIP,
            &mut error as *mut c_int,
        )
    };

    if error != OPUS_OK {
        unsafe {
            if !ptr.is_null() {
                opus_encoder_destroy(ptr);
            }
        }
        panic!(
            "Failed to create Opus encoder: "

```

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

### Codec Creation Functions

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Functions to create decoder and encoder instances for different audio codecs.

```APIDOC
## Create Decoder

### Description
Creates a decoder instance for the specified audio codec type.

### Function Signature
`pub fn create_decoder(codec: CodecType) -> Box<dyn Decoder>`

### Parameters
- **codec** (CodecType) - Required - The type of codec to create a decoder for.

### Returns
- `Box<dyn Decoder>` - An instance of the decoder.

## Create Encoder

### Description
Creates an encoder instance for the specified audio codec type.

### Function Signature
`pub fn create_encoder(codec: CodecType) -> Box<dyn Encoder>`

### Parameters
- **codec** (CodecType) - Required - The type of codec to create an encoder for.

### Returns
- `Box<dyn Encoder>` - An instance of the encoder.
```

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

### Decoder Trait

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/trait.Decoder.html

The Decoder trait defines the interface for decoding audio data. It requires implementations to provide methods for decoding, retrieving the sample rate, and getting the number of channels.

```APIDOC
## Trait Decoder

### Description
Defines the interface for decoding audio data.

### Methods
#### `fn decode(&mut self, data: &[u8]) -> PcmBuf`
Decode encoded audio data into PCM samples.

#### `fn sample_rate(&self) -> u32`
Get the sample rate of the decoded audio.

#### `fn channels(&self) -> u16`
Get the number of channels.
```

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

### QMF Filter and Sample Encoding

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Applies a Quadrature Mirror Filter (QMF) to input samples, calculates low and high band encoded values, and outputs the final code. This is used for processing audio frames.

```rust
self.x[22] = rem[0] as i32;
                self.x[23] = 0;
                let mut sumodd = self.x[0] * QMF_FILTER_COEFS[0];
                sumodd += self.x[2] * QMF_FILTER_COEFS[1];
                sumodd += self.x[4] * QMF_FILTER_COEFS[2];
                sumodd += self.x[6] * QMF_FILTER_COEFS[3];
                sumodd += self.x[8] * QMF_FILTER_COEFS[4];
                sumodd += self.x[10] * QMF_FILTER_COEFS[5];
                sumodd += self.x[12] * QMF_FILTER_COEFS[6];
                sumodd += self.x[14] * QMF_FILTER_COEFS[7];
                sumodd += self.x[16] * QMF_FILTER_COEFS[8];
                sumodd += self.x[18] * QMF_FILTER_COEFS[9];
                sumodd += self.x[20] * QMF_FILTER_COEFS[10];
                sumodd += self.x[22] * QMF_FILTER_COEFS[11];

                let mut sumeven = self.x[1] * QMF_FILTER_COEFS[11];
                sumeven += self.x[3] * QMF_FILTER_COEFS[10];
                sumeven += self.x[5] * QMF_FILTER_COEFS[9];
                sumeven += self.x[7] * QMF_FILTER_COEFS[8];
                sumeven += self.x[9] * QMF_FILTER_COEFS[7];
                sumeven += self.x[11] * QMF_FILTER_COEFS[6];
                sumeven += self.x[13] * QMF_FILTER_COEFS[5];
                sumeven += self.x[15] * QMF_FILTER_COEFS[4];
                sumeven += self.x[17] * QMF_FILTER_COEFS[3];
                sumeven += self.x[19] * QMF_FILTER_COEFS[2];
                sumeven += self.x[21] * QMF_FILTER_COEFS[1];
                sumeven += self.x[23] * QMF_FILTER_COEFS[0];

                let xlow = (sumeven + sumodd) >> 14;
                let xhigh = (sumeven - sumodd) >> 14;
                let ilow = self.encode_low_band(xlow, false);
                let ihigh = self.encode_high_band(xhigh);
                let code = (ihigh << 6 | ilow) >> (8 - self.bits_per_sample);
                self.output_code(code, &mut output);
```

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

### Encoder Trait Definition

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Defines the `Encoder` trait for audio encoding. Implementors must provide methods for encoding PCM samples, getting the input sample rate, and the number of channels.

```rust
pub trait Encoder: Send + Sync {
    /// Encode PCM samples into codec-specific format
    fn encode(&mut self, samples: &[Sample]) -> Vec<u8>;

    /// Get the sample rate expected for input samples
    fn sample_rate(&self) -> u32;

    /// Get the number of channels expected for input
    fn channels(&self) -> u16;
}
```

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

### Create New OpusDecoder Instance

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/opus/struct.OpusDecoder.html

Creates a new Opus decoder instance with a specified sample rate and number of channels. Ensure the sample rate and channel count are compatible with the Opus format.

```rust
pub fn new(sample_rate: u32, channels: u16) -> Self
```

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

### Opus Decoder Creation

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/opus.rs.html

Initializes a new Opus decoder instance. Panics if decoder creation fails, ensuring a valid decoder is always available.

```rust
pub fn new(sample_rate: u32, channels: u16) -> Self {
    let channel_count: c_int = if channels == 1 { 1 } else { 2 };
    let mut error: c_int = 0;
    let ptr = unsafe {
        opus_decoder_create(
            sample_rate as c_int,
            channel_count,
            &mut error as *mut c_int,
        )
    };

    if error != OPUS_OK {
        unsafe {
            if !ptr.is_null() {
                opus_decoder_destroy(ptr);
            }
        }
        panic!(
            "Failed to create Opus decoder: {}",
            opus_error_message(error)
        );
    }

    let decoder = NonNull::new(ptr).unwrap_or_else(|| {
        panic!("Failed to create Opus decoder: null pointer returned");
    });

    Self {
        decoder,
        sample_rate,
        channels: if channel_count == 1 { 1 } else { 2 },
    }
}
```

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

### Bytes to Samples Conversion

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Utilities for converting `&[u8]` byte slices to `PcmBuf` (which is a `Vec<Sample>`), considering the target system's endianness.

```APIDOC
## `bytes_to_samples(u8_data: &[u8]) -> PcmBuf`

Converts a byte slice into a `PcmBuf` (vector of audio samples).

### Behavior based on endianness:

- **Little-endian**: Directly reinterprets the byte slice as a slice of `Sample` and converts it to a vector.
- **Big-endian**: Interprets every two bytes as a little-endian `i16` sample and collects them into a `PcmBuf`.
```

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

### Resampler Structure and Constructor

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/resampler.rs.html

Details the Resampler struct, which is a Polyphase FIR Resampler suitable for VoIP, and its associated constructor `new`.

```APIDOC
## struct Resampler

### Description
A Polyphase FIR Resampler suitable for VoIP.

### Fields
- **input_rate** (usize) - The input audio sample rate.
- **output_rate** (usize) - The output audio sample rate.
- **ratio** (f64) - The ratio between output and input rates.
- **coeffs** (Vec<f32>) - The filter coefficients.
- **num_phases** (usize) - The number of filter phases.
- **taps_per_phase** (usize) - The number of taps per filter phase.
- **history** (Vec<f32>) - Stores past input samples for filtering.
- **current_pos** (f64) - Current position within the resampling process.

### Method
`Resampler::new(input_rate: usize, output_rate: usize) -> Self`

### Description
Creates a new `Resampler` instance.

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
None

### Response
#### Success Response (200)
- **Self** (Resampler) - A new Resampler instance.

#### Response Example
None
```

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

### Create Default Opus Encoder

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/opus.rs.html

Creates a default Opus encoder configured for 48kHz sample rate and stereo channels. If the 'opus_mono' feature is enabled, it defaults to mono.

```rust
pub fn new_default() -> Self {
        #[cfg(feature = "opus_mono")]
        {
            return Self::new(48000, 1);
        }
        Self::new(48000, 2)
    }
```

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

### Create Default OpusDecoder

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/opus/struct.OpusDecoder.html

Creates a default Opus decoder instance configured for 48kHz sample rate and stereo channels. This is a convenient way to initialize the decoder for common use cases.

```rust
pub fn new_default() -> Self
```

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

### G.722 Bitrate Bits Per Sample Method

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Method to determine the number of bits per sample for a given G.722 bitrate. Use this to understand the sample resolution for each mode.

```rust
impl Bitrate {
    fn bits_per_sample(&self) -> i32 {
        match self {
            Bitrate::Mode1_64000 => 8,
            Bitrate::Mode2_56000 => 7,
            Bitrate::Mode3_48000 => 6,
        }
    }
}
```

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

### Resample audio from 16kHz to 8kHz

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/resampler.rs.html

Tests the resampling functionality from a 16kHz input sample rate to an 8kHz output sample rate. Asserts that the output length is within an expected range and that the resampled values are close to the original.

```rust
#[test]
    fn test_resample_16k_to_8k() {
        let mut resampler = Resampler::new(16000, 8000);
        let input = vec![1000i16; 160];
        let output = resampler.resample(&input);
        assert!(output.len() >= 75 && output.len() <= 85);
        for &s in &output[20..output.len() - 20] {
            assert!((s - 1000).abs() < 100, "Value {} is too far from 1000", s);
        }
    }
```

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

### Resample audio from 8kHz to 16kHz

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/resampler.rs.html

Tests the resampling functionality from an 8kHz input sample rate to a 16kHz output sample rate. Asserts that the output length is within an expected range and that the resampled values are close to the original.

```rust
#[test]
    fn test_resample_8k_to_16k() {
        let mut resampler = Resampler::new(8000, 16000);
        let input = vec![1000i16; 80];
        let output = resampler.resample(&input);
        assert!(output.len() >= 150 && output.len() <= 170);
        for &s in &output[20..output.len() - 20] {
            assert!((s - 1000).abs() < 100, "Value {} is too far from 1000", s);
        }
    }
```

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

### Audio Configuration API

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/pcma.rs.html

Provides methods to retrieve the sample rate and number of channels for the audio codec.

```APIDOC
## GET /config

### Description
Retrieves the configuration details of the audio codec, including sample rate and channels.

### Method
GET

### Endpoint
/config

### Response
#### Success Response (200)
- **sample_rate** (u32) - The sample rate of the audio codec (e.g., 8000 Hz).
- **channels** (u16) - The number of audio channels supported (e.g., 1 for mono).

#### Response Example
```json
{
  "sample_rate": 8000,
  "channels": 1
}
```
```

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

### Audio Codec Crate Overview

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/index.html

This section provides an overview of the audio-codec crate, including its re-exports, modules, enums, traits, and functions.

```APIDOC
## Crate audio_codec

### Re-exports

- `pub use resampler::Resampler;`
- `pub use resampler::resample;`

### Modules

- `g722`
- `g729`
- `opus`
- `pcma`
- `pcmu`
- `resampler`
- `telephone_event`

### Enums

- `CodecType`

### Traits

- `Decoder`
- `Encoder`

### Functions

- `bytes_to_samples`
- `create_decoder`
- `create_encoder`
- `samples_to_bytes`

### Type Aliases

- `PcmBuf`
- `Sample`
```

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

### G.722 Decoder Constructor (Default)

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Creates a new G.722 decoder instance with default options (64 kbit/s, non-packed, non-8kHz).

```rust
pub fn new() -> Self {
    Self::with_options(Bitrate::Mode1_64000, false, false)
}
```

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

### Encode 16-bit PCM samples into G.722 format (16kHz mode)

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Encodes audio samples in 16kHz mode, processing pairs of samples. This involves applying QMF filters, encoding both low and high bands, and combining them into a single code.

```rust
else {
            // Process all input samples in 16kHz mode
            // Use chunks_exact(2) for better performance and to avoid bound checks
            let chunks = amp.chunks_exact(2);
            let rem = chunks.remainder();

            for chunk in chunks {
                // Shuffle buffer down to make room for new samples
                self.x.copy_within(2..24, 0);

                // Add new samples to buffer
                self.x[22] = chunk[0] as i32;
                self.x[23] = chunk[1] as i32;

                // Apply QMF filter to split input into bands
                // Unrolled loop for 12 coefficients
                let mut sumodd = self.x[0] * QMF_FILTER_COEFS[0];
                sumodd += self.x[2] * QMF_FILTER_COEFS[1];
                sumodd += self.x[4] * QMF_FILTER_COEFS[2];
                sumodd += self.x[6] * QMF_FILTER_COEFS[3];
                sumodd += self.x[8] * QMF_FILTER_COEFS[4];
                sumodd += self.x[10] * QMF_FILTER_COEFS[5];
                sumodd += self.x[12] * QMF_FILTER_COEFS[6];
                sumodd += self.x[14] * QMF_FILTER_COEFS[7];
                sumodd += self.x[16] * QMF_FILTER_COEFS[8];
                sumodd += self.x[18] * QMF_FILTER_COEFS[9];
                sumodd += self.x[20] * QMF_FILTER_COEFS[10];
                sumodd += self.x[22] * QMF_FILTER_COEFS[11];

                let mut sumeven = self.x[1] * QMF_FILTER_COEFS[11];
                sumeven += self.x[3] * QMF_FILTER_COEFS[10];
                sumeven += self.x[5] * QMF_FILTER_COEFS[9];
                sumeven += self.x[7] * QMF_FILTER_COEFS[8];
                sumeven += self.x[9] * QMF_FILTER_COEFS[7];
                sumeven += self.x[11] * QMF_FILTER_COEFS[6];
                sumeven += self.x[13] * QMF_FILTER_COEFS[5];
                sumeven += self.x[15] * QMF_FILTER_COEFS[4];
                sumeven += self.x[17] * QMF_FILTER_COEFS[3];
                sumeven += self.x[19] * QMF_FILTER_COEFS[2];
                sumeven += self.x[21] * QMF_FILTER_COEFS[1];
                sumeven += self.x[23] * QMF_FILTER_COEFS[0];

                // Scale filter outputs to get low and high bands
                let xlow = (sumeven + sumodd) >> 14;
                let xhigh = (sumeven - sumodd) >> 14;

                // 16kHz mode - encode both bands
                let ilow = self.encode_low_band(xlow, false);
                let ihigh = self.encode_high_band(xhigh);
                let code = (ihigh << 6 | ilow) >> (8 - self.bits_per_sample);

                // Output the encoded code
                self.output_code(code, &mut output);
            }

            if !rem.is_empty() {
                self.x.copy_within(2..24, 0);
            }
        }
```

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

### resample Function

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/resampler/fn.resample.html

The `resample` function takes input audio samples, their sample rate, and the desired output sample rate to perform resampling.

```APIDOC
## resample

### Description
Resamples audio data from an input sample rate to an output sample rate.

### Method
Rust Function

### Endpoint
audio_codec::resampler::resample

### Parameters
#### Path Parameters
None

#### Query Parameters
None

#### Request Body
None

### Request Example
```rust
// Example usage (conceptual, actual types may vary)
pub fn resample(
    input: &[Sample],
    input_sample_rate: u32,
    output_sample_rate: u32,
) -> PcmBuf
```

### Response
#### Success Response (PcmBuf)
- **PcmBuf** (type) - The resampled audio data buffer.

#### Response Example
```rust
// Conceptual representation of the returned PcmBuf
// let resampled_audio: PcmBuf = resample(&input_samples, 44100, 48000);
```
```

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

### PcmuDecoder Methods

Source: https://docs.rs/audio-codec/0.3.30/audio_codec/pcmu/struct.PcmuDecoder.html

Details on the methods available for the PcmuDecoder struct, including instantiation and decoding.

```APIDOC
## Implementations

### impl PcmuDecoder

#### pub fn new() -> Self

Creates a new PcmuDecoder instance.
```

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

### Encode 16-bit PCM samples into G.722 format (8kHz mode)

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/g722.rs.html

Encodes audio samples in 8kHz mode, directly using input values and scaling for the low band. Only the low band is processed in this mode.

```rust
if self.eight_k {
            while input_idx < amp.len() {
                // 8kHz mode - Just use input directly with scaling
                let xlow = amp[input_idx] as i32 >> 1;
                input_idx += 1;

                // 8kHz mode - only low band matters
                let code = self.encode_low_band(xlow, true);
                self.output_code(code, &mut output);
            }
        }
```

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

### A-law Encoding Algorithm

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/pcma.rs.html

Implements the A-law (PCMA) encoding algorithm. Handles sign, magnitude scaling, and quantization. Special cases for small negative values and i16::MIN are addressed.

```rust
const fn linear2alaw_algo(pcm_val: i16) -> u8 {
    // Special case handling for small negative values [-8, -1]
    if pcm_val < 0 && pcm_val >= -8 {
        return 0xD5;
    }

    // Determine sign mask and prepare the positive sample value
    let (mask, abs_val) = if pcm_val >= 0 {
        (0xD5, pcm_val) // sign bit = 1
    } else {
        // Handle the edge case of -32768 (i16::MIN), which would overflow when negated
        if pcm_val == i16::MIN {
            (0x55, i16::MAX) // Use the maximum positive value
        } else {
            (0x55, -pcm_val - 8) // sign bit = 0
        }
    };

    // Convert the scaled magnitude to segment number
    let seg = search(abs_val, &SEG_END, 8);

    // If out of range, return maximum value
    if seg >= 8 {
        return (0x7F ^ mask) as u8;
    }

    // Calculate the base value from segment
    let aval = (seg as i16) << SEG_SHIFT;

    // Combine the segment value with the quantization bits
    let shift = if seg < 2 { 4 } else { seg as i16 + 3 };
    let result = aval | ((abs_val >> shift) & QUANT_MASK);

    // Apply the mask to set the sign bit
    (result ^ mask) as u8
}
```

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

### Optimized Dot Product for ARM Neon

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/resampler.rs.html

Implements a dot product using ARM Neon intrinsics for `aarch64`. This function is unsafe and requires the `aarch64` target architecture.

```rust
unsafe {
            use std::arch::aarch64::*;
            let mut sumv = vdupq_n_f32(0.0);
            for i in (0..16).step_by(4) {
                let av = vld1q_f32(a.as_ptr().add(i));
                let bv = vld1q_f32(b.as_ptr().add(i));
                sumv = vfmaq_f32(sumv, av, bv);
            }
            vaddvq_f32(sumv)
        }
```

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

### Default Opus Decoder Creation

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/opus.rs.html

Creates a default Opus decoder configured for 48kHz sample rate and stereo channels. Includes a feature flag for mono support.

```rust
pub fn new_default() -> Self {
    #[cfg(feature = "opus_mono")]
    {
        return Self::new(48000, 1);
    }
    Self::new(48000, 2)
}
```

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

### Convert samples to bytes (little-endian)

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/lib.rs.html

Converts a slice of Sample to a Vec<u8> using unsafe operations for little-endian systems. Assumes Sample has a layout compatible with u8.

```rust
#[cfg(target_endian = "little")]
pub fn samples_to_bytes(samples: &[Sample]) -> Vec<u8> {
    unsafe {
        std::slice::from_raw_parts(
            samples.as_ptr() as *const u8,
            samples.len() * std::mem::size_of::<Sample>(),
        )
        .to_vec()
    }
}
```

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

### Generic resampling function

Source: https://docs.rs/audio-codec/0.3.30/src/audio_codec/resampler.rs.html

Provides a convenient function to resample audio data between two sample rates. If the input and output sample rates are the same, it returns the input data directly.

```rust
pub fn resample(input: &[Sample], input_sample_rate: u32, output_sample_rate: u32) -> PcmBuf {
    if input_sample_rate == output_sample_rate {
        return input.to_vec();
    }
    let mut r = Resampler::new(input_sample_rate as usize, output_sample_rate as usize);
    r.resample(input)
}
```
Tokens:
Raw