SPH.jl

Build status:

julia v0.7
julia v1.0

Julia sphere file reader/writer. Shamelessly stolen from the excellent WAV.jl package by Dan Casimiro.

Installation

julia> Pkg.add("SPH")

Getting Started

SPH provides sphread, sphwrite, and sph2wav commands to read, write, and convert SPH files. Here is an example to get you started. It generates some data, writes it to a file and then reads the data back. sph2wav is then used to convert the SPH file to a WAV file. sphreadheader is also provided for reading an SPH header.

julia> using SPH
julia> header = Dict{String, Any}(
  "channel_count" => 1,
  "sample_coding" => "pcm",
  "sample_rate" => 8000,
  "sample_count" => 8000,
  "sample_byte_format" => "0123",
  "sample_n_bytes" => 4
)
julia> samples = sin.(2 * pi * [0:7999;] * 440.0 / 8000) * 0.01
julia> sphwrite(header, samples, "example.sph")
julia> header, x = sphread("example.sph")
julia> sph2wav("example.sph", "example.wav")
julia> h = sphreadheader("example.sph")

Note

sphread and sphwrite currently do not obey the sample_byte_format in the SPH header. If this is an issue for you, let me know and I can add this functionality.

sphreadheader

function sphreadheader(io::IO)
function sphread(filename::AbstractString)

Return a Dict{String, Any} corresponding to the Sphere header with Julian typing. e.g.

Dict{String, Any}(
    "channel_count"      => 1,
    "sample_coding"      => "pcm",
    "sample_byte_format" => "01",
    "sample_rate"        => 8000,
    "sample_n_bytes"     => 4,
    "sample_count"       => 8000
)

sphread

This function reads the samples from a NIST Sphere file. The samples are converted to floating point values in the range from -1.0 to 1.0 by default.

function sphread(io::IO; subrange=Any, format="double")
function sphread(filename::AbstractString; subrange=Any, format="double")

The available options, and the default values, are:

format (default = double): changes the format of the returned samples. The string double returns double precision floating point values in the range -1.0 to 1.0. The string native returns the values as encoded in the file. The string size returns the number of samples in the file, rather than the actual samples.
subrange (default = Any): controls which samples are returned. The default, Any returns all of the samples. Passing a number (Real), N, will return the first N samples of each channel. Passing a range (Range1{Real}), R, will return the samples in that range of each channel.

The returned values are:

header: The SPH header; same as returned by sphreadheader
samples: The acoustic samples; A matrix is returned for files that contain multiple channels.

sphwrite

Writes samples to an SPH file. Each column of the data represents a different channel. Stereo files should contain two columns.

function sphwrite(header, samples, io::IO)
function sphwrite(header, samples, filename::AbstractString)