PortAudio.jl/examples/measure_latency.jl
2021-06-01 13:44:23 -04:00

65 lines
1.6 KiB
Julia

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; is_warmup = false)
in_stream = PortAudioStream(1, 0; latency = in_latency)
out_stream = PortAudioStream(0, 1; latency = out_latency)
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 $diff_in_ms ms is bigger than 1 ms"
end
delay = finddelay(recorded, signal) / 48000
return trunc(Int, delay * 1000)# result in ms
end
measure_latency(0.1, 0.1; is_warmup = true) # warmup
latencies = [0.1, 0.01, 0.005]
for in_latency in latencies
for out_latency in latencies
measure = measure_latency(in_latency, out_latency)
println("$measure ms latency for in_latency=$in_latency, out_latency=$out_latency")
end
end