First dig at reading WAV PCM samples from pipe, addressing dancasimir…

…o#80
davidavdav · Nov 7, 2019 · 4b90c12 · 4b90c12
1 parent b39e0ff
commit 4b90c12
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Showing 2 changed files with 40 additions and 7 deletions.
diff --git a/src/WAV.jl b/src/WAV.jl
@@ -248,25 +248,40 @@ end
 
 ieee_float_container_type(nbits) = (nbits == 32 ? Float32 : (nbits == 64 ? Float64 : error("$nbits bits is not supported for WAVE_FORMAT_IEEE_FLOAT.")))
 
+## ignore skip for pipelines
+function Base.skip(::Base.Process, Uint64) end
+function Base.skip(::Base.ProcessChain, Uint64) end
+
+function read_raw_sample(io::IO, len::Integer)
+    ispipe = isa(io, Union{Base.Process, Base.ProcessChain})
+    if ispipe
+        return read(io)
+    else
+        return read(io, len)
+    end
+end
+
 function read_pcm_samples(io::IO, fmt::WAVFormat, subrange)
     nbits = bits_per_sample(fmt)
     if isempty(subrange)
         return Array{pcm_container_type(nbits), 2}(undef, 0, fmt.nchannels)
     end
-    samples = Array{pcm_container_type(nbits), 2}(undef, length(subrange), fmt.nchannels)
-    sample_type = eltype(samples)
+    nrange = length(subrange)
+    nchan = Int(fmt.nchannels)
+    sample_type = pcm_container_type(nbits)
     nbytes = ceil(Integer, nbits / 8)
     bitshift = [0x0, 0x8, 0x10, 0x18, 0x20, 0x28, 0x30, 0x38, 0x40]
     mask = UInt64(0x1) << (nbits - 1)
     if nbits <= 8
         mask = UInt64(0)
     end
     skip(io, convert(UInt, (first(subrange) - 1) * nbytes * fmt.nchannels))
-    raw_sample = Vector{UInt8}(undef, nbytes*length(samples))
-    read!(io, raw_sample)
-    raw_sample = reshape(raw_sample, nbytes, size(samples, 2), size(samples, 1))
-    for i = 1:size(samples, 1)
-        for j = 1:size(samples, 2)
+    raw_sample = read_raw_sample(io, nbytes * nrange * nchan)
+    nrange = length(raw_sample) ÷ (nbytes * nchan)
+    raw_sample = reshape(raw_sample, nbytes, nchan, nrange)
+    samples = Matrix{sample_type}(undef, nrange, nchan)
+    for i = 1:nrange
+        for j = 1:nchan
             my_sample = UInt64(0)
             for k = 1:nbytes
                 my_sample |= convert(UInt64, raw_sample[k,j,i]) << bitshift[k]

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -646,3 +646,21 @@ end
     #WAV.wavplay(in_data, fs);
     #WAV.wavplay([in_data in_data], fs);
 end
+
+## Read from pipeline, not knowing the length of the wav file that is read #80
+## This expects "sox" to be installed
+@testset "14" begin
+    x = [0:7999;]
+    y = sin.(2 * pi * x / 8000)
+    testfile = "example.wav"
+    WAV.wavwrite(y, testfile, Fs=8000)
+    for pipe in [`sox $testfile -t wav -r 16000 -c 1 -b 16 - speed 1.1`, 
+            pipeline(`sox $testfile -t wav -r 16000 -c 1 -b 16 - speed 1.1`),
+            pipeline(`sox $testfile -t wav -r 16000 -c 1 -b 16 -`, `sox -t wav - -t wav - speed 1.1`)]
+        io = open(pipe)
+        x, Fs = WAV.wavread(io) 
+        @assert Fs == 16000
+        @assert 16000/1.11 < length(x) < 16000/1.09
+    end
+    rm(testfile)
+end