Struct ALAW 

pub struct ALAW(/* private fields */);

A-law companded sample, as defined by ITU-T G.711. Stored as 1 byte. A single byte has no byte order, so there are no little endian and big endian variants.

A-law fits the dynamic range of a 13 bit linear value into 8 bits, using a piecewise linear approximation of a logarithmic curve. The closest numeric type is i16, and the decoded values are scaled to that range. The largest representable magnitude is 32256, so the range does not quite reach the limits of an i16. A-law has no code for exact silence, the two smallest magnitudes are +8 and -8.

Note that i16 is wider than the 256 values this format can represent, so unlike the linear formats, from_number quantizes and a number does not survive a roundtrip unchanged. Quantizing an already quantized value changes nothing further.

Note that a byte value of zero is not silence. It decodes to -5504. The A-law code for the smallest positive value is 0xD5.

This is the format used for telephony in Europe and most of the world. It appears as WAVE_FORMAT_ALAW in wav files, as PCMA in RTP streams, and as SND_PCM_FORMAT_A_LAW in ALSA.

Trait Implementations

impl BytesSample for ALAW

const BYTES_PER_SAMPLE: usize = 1

The number of bytes making up each sample value.

type NumericType = i16

The closest matching numeric type.

fn zero() -> Self

Create a sample with all bytes set to zero.

fn from_slice(bytes: &[u8]) -> Self

Create a new ByteSample from a slice of raw bytes. The slice length must be at least the number of bytes for a sample value.

fn as_slice(&self) -> &[u8]

Return the raw bytes as a slice.

fn as_mut_slice(&mut self) -> &mut [u8]

Return the raw bytes as a mutable slice.

fn to_number(&self) -> Self::NumericType

Convert the raw bytes to a numerical value.

fn from_number(value: Self::NumericType) -> Self

Convert a numerical value to raw bytes.

impl Clone for ALAW

fn clone(&self) -> ALAW

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for ALAW

impl Debug for ALAW

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.