wavfile.chunk module

Chunk-based helper classes for working with RIFF files.

class wavfile.chunk.RiffFormat(value)

Bases: Enum

RIFF file format

WAVE: RiffFormat = b'WAVE'
class wavfile.chunk.ChunkID(value)

Bases: Enum

RIFF chunk identifiers

RIFF_CHUNK: ChunkID = b'RIFF'
FMT_CHUNK: ChunkID = b'fmt '
DATA_CHUNK: ChunkID = b'data'
UNKNOWN_CHUNK: ChunkID = b'    '
class wavfile.chunk.WavFormat(value)

Bases: Enum

Wav audio data format

PCM: WavFormat = 1
IEEE_FLOAT: WavFormat = 3
class wavfile.chunk.Chunk(fp: IO, bigendian: bool = False)

Bases: object

Chunk read and write

align: int = 2
offset: int = 8
__init__(fp: IO, bigendian: bool = False) → None

Initialise the chunk from a file pointer.

Parameters

  • fp – Open file pointer.

  • bigendian – Is the file bid endian?

fp: Optional[IO]
bigendian: bool
start: int
chunk_id: Optional[ChunkID]
size: int
property endianness: str

The endianness in text form.

property content_start: int

The start position of the chunk content

skip() → None

Skip to the end of the chunk.

read(nbytes: int) → bytes

Read data from the chunk.

Parameters

nbytes – The number of bytes to read.

Returns

The data.

write(data: bytes) → None

Write data to the chunk. Adjust the chunk size accordingly.

Parameters

data – Data to write to the chunk.

write_header() → None

Write the chunk header to the file, esp. the updated chunk size.

bytes_to_int(data: bytes, signed: bool = True) → int

Read a signed integer from the specified number of bytes of the input chunk.

Parameters

  • data – Input bytes to interpret as a signed integer.

  • signed – Is the integer signed?

Returns

The integer value.

read_int(nbytes: int, signed: bool = True) → int

Read an integer from the chunk.

Parameters

  • nbytes – Number of bytes encoding the integer.

  • signed – Whether the integer is signed.

Returns

The integer value.

int_to_bytes(data: int, nbytes: int, signed: bool = True) → bytes

Convert an integer to bytes.

Parameters

  • data – The integer to encode.

  • nbytes – Number of bytes encoding the integer.

  • signed – Whether the integer is signed.

Returns

The bytes.

write_int(data: int, nbytes: int, signed: bool = True) → None

Write an integer to the chunk.

Parameters

  • data – The integer to encode.

  • nbytes – Number of bytes encoding the integer.

  • signed – Whether the integer is signed.

bytes_to_float(data: bytes) → float

Read a float from the specified number of bytes of the input chunk.

Parameters

data – Input bytes to interpret as a float.

Returns

The float value.

read_float(nbytes: int) → float

Read a float from the chunk.

Parameters

nbytes – Number of bytes encoding the float.

Returns

The float value.

float_to_bytes(data: float, nbytes: int) → bytes

Convert a float to bytes.

Parameters

  • data – The float to encode.

  • nbytes – Number of bytes encoding the float.

Returns

The bytes.

write_float(data: float, nbytes: int) → None

Write a float to the chunk.

Parameters

  • data – The float to encode.

  • nbytes – Number of bytes encoding the float.

close() → None

Close the chunk and update the header.

class wavfile.chunk.RiffChunk(fp: IO)

Bases: Chunk

Riff container chunk read and write

__init__(fp: IO) → None

Initialise the chunk from a file pointer.

Parameters

fp – Open file pointer.

format: RiffFormat
close() → None

Close the chunk and update the header.

class wavfile.chunk.WavFmtChunk(fp: IO)

Bases: Chunk

Wave format chunk read and write

__init__(fp: IO) → None

Initialise the chunk from a file pointer.

Parameters

fp – Open file pointer.

audio_fmt: WavFormat
num_channels: int
sample_rate: int
byte_rate: int
block_align: int
bits_per_sample: int
property bytes_per_sample: int

Number of bytes per audio sample

property signed: bool

Whether the integer representation is signed

write_fmt() → None

Write the format data to the file.

close() → None

Close the chunk and update the header and format data.

class wavfile.chunk.WavDataChunk(fp: IO, fmt_chunk: WavFmtChunk)

Bases: Chunk

Wave data chunk read and write

__init__(fp: IO, fmt_chunk: WavFmtChunk) → None

Initialise the chunk from a file pointer.

Parameters

  • fp – Open file pointer.

  • fmt_chunk – The associated format chunk.

fmt_chunk: WavFmtChunk
property num_frames: int

Number of audio frames in the file

close() → None

Close the chunk and update the header and format data.

read_sample() → Union[int, float]

Read a sample from the chunk.

read_frames(nframes: Optional[int] = None) → List[List[Union[int, float]]]

Read a number of audio frames from the chunk. A frame is a collection of samples, from each audio channel, associated with a single time instant.

Parameters

nframes – Number of audio frames to read.

Returns

The audio frames as a list of lists.

write_sample(sample: Union[int, float]) → None

Write a sample to the chunk.

Parameters

sample – An audio sample.

write_frames(audio: List[List[Union[int, float]]]) → None

Write one or more frames of audio to the chunk.

Parameters

audio – The audio frames as a list of lists.

seek(frame_number: int, whence: int = 0) → WavDataChunk

Move to the specified frame number. The frame positioning mode whence are: 0 (default) = absolute positioning, 1 = relative to current position, 2 = relative to end of last frame.

Parameters

  • frame_number – The frame number.

  • whence – The frame positioning mode.

Returns

The method returns the object.

tell() → int

Get the current frame number.