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.

julia> Pkg.add("SPH")

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")

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.

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
)

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.

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)