Merge branch 'nocallback' of https://github.com/jakubwro/PortAudio.jl

examples/measure_latency.jl

@@ -0,0 +1,68 @@
+using PortAudio
+using DSP
+
+function create_measure_signal()
+    signal = zeros(Float32, 20000)
+    for i in 1:3
+        signal = vcat(signal, rand(Float32, 100), zeros(Float32, i*10000))
+    end
+    return signal
+end
+
+function measure_latency(in_latency = 0.1, out_latency=0.1, blocksize = 32; is_warmup = false)
+
+    in_stream = PortAudioStream(1,0; latency=in_latency, blocksize=32)
+    out_stream = PortAudioStream(0,1; latency=out_latency, blocksize=32)
+
+    cond = Base.Event()
+
+    writer_start_time = Int64(0)
+    reader_start_time = Int64(0)
+
+    reader = Threads.@spawn begin
+        wait(cond)
+        writer_start_time = time_ns() |> Int64
+        return read(in_stream, 100000)
+    end
+
+    signal = create_measure_signal()
+    writer = Threads.@spawn begin
+            wait(cond)
+            reader_start_time = time_ns() |> Int64
+            write(out_stream, signal)
+    end
+
+    notify(cond)
+
+    wait(reader)
+    wait(writer)
+
+    recorded = collect(reader.result)[:,1]
+    
+    close(in_stream)
+    close(out_stream)
+
+    diff = reader_start_time - writer_start_time |> abs
+
+    diff_in_ms = diff / 10^6 # 1 ms = 10^6 ns
+
+    if !is_warmup && diff_in_ms > 1
+        @warn "Threads start time difference $diff_in_ms ms is bigger than 1 ms"
+    end
+
+    delay = finddelay(recorded, signal) / 48000
+
+    return trunc(Int, delay * 1000)# result in ms
+end
+
+measure_latency(0.1, 0.1, 32; is_warmup = true) # warmup
+
+latencies = [0.1, 0.01, 0.005]
+for in_latency in latencies
+    for out_latency in latencies
+        for blocksize in [32]
+            measure = measure_latency(in_latency, out_latency, blocksize)
+            println("$measure ms latency for in_latency=$in_latency, out_latency=$out_latency, blocksize=$blocksize")
+        end
+    end
+end

src/PortAudio.jl

@@ -78,15 +78,15 @@ mutable struct PortAudioStream{T}
     # TODO: write a latency tester app
     function PortAudioStream{T}(indev::PortAudioDevice, outdev::PortAudioDevice,
                                 inchans, outchans, sr, blocksize,
-                                warn_xruns) where {T}
+                                warn_xruns, latency) where {T}
         inchans = inchans == -1 ? indev.maxinchans : inchans
         outchans = outchans == -1 ? outdev.maxoutchans : outchans
         inparams = (inchans == 0) ?
             Ptr{Pa_StreamParameters}(0) :
-            Ref(Pa_StreamParameters(indev.idx, inchans, type_to_fmt[T], 0.1, C_NULL))
+            Ref(Pa_StreamParameters(indev.idx, inchans, type_to_fmt[T], latency, C_NULL))
         outparams = (outchans == 0) ?
             Ptr{Pa_StreamParameters}(0) :
-            Ref(Pa_StreamParameters(outdev.idx, outchans, type_to_fmt[T], 0.1, C_NULL))
+            Ref(Pa_StreamParameters(outdev.idx, outchans, type_to_fmt[T], latency, C_NULL))
         this = new(sr, blocksize, C_NULL, warn_xruns)
         # finalizer(close, this)
         this.sink = PortAudioSink{T}(outdev.name, this, outchans)
@@ -127,7 +127,7 @@ Options:
 """
 function PortAudioStream(indev::PortAudioDevice, outdev::PortAudioDevice,
         inchans=2, outchans=2; eltype=Float32, samplerate=-1, blocksize=DEFAULT_BLOCKSIZE,
-        warn_xruns=false)
+        warn_xruns=false, latency=0.1)
     if samplerate == -1
         sampleratein = indev.defaultsamplerate
         samplerateout = outdev.defaultsamplerate
@@ -142,7 +142,7 @@ function PortAudioStream(indev::PortAudioDevice, outdev::PortAudioDevice,
             samplerate = samplerateout
         end
     end
-    PortAudioStream{eltype}(indev, outdev, inchans, outchans, samplerate, blocksize, warn_xruns)
+    PortAudioStream{eltype}(indev, outdev, inchans, outchans, samplerate, blocksize, warn_xruns, latency)
 end
 
 # handle device names given as streams