sndwrite

sndfileio.sndwrite(outfile, samples, sr, encoding='default', fileformat=None, normalize_if_clipping=True, metadata=None, **options)[source]

Write all samples to a soundfile.

Parameters:

  • outfile (str) – The name of the outfile. the extension will determine the file-format. The formats supported depend on the available backends.

  • samples (ndarray) – Array-like. the actual samples. The shape determines the number of channels of outfile. For 1 channel, shape=(nframes,) or shape=(nframes, 1). For multichannel audio, shape=(nframes, nchannels).

  • sr (int) – Sampling-rate

  • encoding – one of “pcm16”, “pcm24”, “pcm32”, “pcm64”, “float32”, “float64”, “auto” to guess an encoding and “default” to use the default encoding for the given format.

  • fileformat (Optional[str]) – if given, will override the format indicated by the extension

  • normalize_if_clipping – prevent clipping by normalizing samples before writing. This only makes sense when writing pcm data

  • metadata (Optional[dict[str, str]]) – a dict of str: str, with possible keys ‘title’, ‘comment’, ‘artist’, ‘album’, ‘tracknumber’, ‘software’ (the creator of a soundfile)

  • options – available options depend on the fileformat.

Return type:

None

Options

mp3:

  • bitrate: bitrate in Kb/s (int, default=160)

  • quality: 1-7, 1 is highest and 7 is fastest, default=3

For lossless formats, like wav, aif, flac, etc., there are no extra options

Note

Not all file formats support all encodings. Raises SndfileError if the format does not support the given encoding. If set to ‘auto’, an encoding will be selected based on the file-format and on the data. The bitdepth of the data is measured, and if the file-format supports it, it will be used. For bitdepths of 8, 16 and 24 bits, a PCM encoding will be used. For a bitdepth of 32 bits, a FLOAT encoding will be used, or the next lower supported encoding. If ‘default’ is given as encoding, the default encoding for the format is used

Format

Default encoding

wav

float32

aif

float32

flac

pcm24

mp3

pcm16

Example

# Normalize and save as flac
>>> samples, sr = sndread("sndfile.wav")
>>> maxvalue = max(samples.max(), -samples.min())
>>> samples *= 1/maxvalue
>>> sndwrite("out.flac", samples, sr)