Object pascal examples for recording and playing audio with portaudio. (

#1271)

The recording example can be used for speech recognition while the playing example can be used for text to speech.

The portaudio wrapper for object pascal is copied from
https://github.com/UltraStar-Deluxe/USDX/blob/master/src/lib/portaudio/portaudio.pas

pascal-api-examples/portaudio-test/.gitignore

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+test-record
+test-play

pascal-api-examples/portaudio-test/README.md

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+# Introduction
+
+[portaudio.pas](./portaudio.pas)
+requires that the portaudio library is installed on your system.
+
+
+On macOS, you can use
+
+```bash
+brew install portaudio
+```
+
+and it will install `portaudio` into `/usr/local/Cellar/portaudio/19.7.0`.

pascal-api-examples/portaudio-test/run-test-play.sh

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+#!/usr/bin/env bash
+
+set -ex
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+SHERPA_ONNX_DIR=$(cd $SCRIPT_DIR/../.. && pwd)
+
+echo "SHERPA_ONNX_DIR: $SHERPA_ONNX_DIR"
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/install/lib/libsherpa-onnx-c-api.so && ! -f ../../build/install/lib/sherpa-onnx-c-api.dll ]]; then
+  mkdir -p ../../build
+  pushd ../../build
+  cmake \
+    -DCMAKE_INSTALL_PREFIX=./install \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    ..
+
+  cmake --build . --target install --config Release
+  popd
+fi
+
+fpc \
+  -g \
+  -dSHERPA_ONNX_USE_SHARED_LIBS \
+  -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
+  -Fl/usr/local/Cellar/portaudio/19.7.0/lib \
+  ./test-play.pas
+
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
+
+./test-play

pascal-api-examples/portaudio-test/run-test-record.sh

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+#!/usr/bin/env bash
+
+set -ex
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+SHERPA_ONNX_DIR=$(cd $SCRIPT_DIR/../.. && pwd)
+
+echo "SHERPA_ONNX_DIR: $SHERPA_ONNX_DIR"
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/install/lib/libsherpa-onnx-c-api.so && ! -f ../../build/install/lib/sherpa-onnx-c-api.dll ]]; then
+  mkdir -p ../../build
+  pushd ../../build
+  cmake \
+    -DCMAKE_INSTALL_PREFIX=./install \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    ..
+
+  cmake --build . --target install --config Release
+  popd
+fi
+
+fpc \
+  -g \
+  -dSHERPA_ONNX_USE_SHARED_LIBS \
+  -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
+  -Fl/usr/local/Cellar/portaudio/19.7.0/lib \
+  ./test-record.pas
+
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
+
+./test-record

pascal-api-examples/portaudio-test/test-play.pas

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+{ Copyright (c)  2024  Xiaomi Corporation }
+{
+This file shows how to use portaudio for playing.
+
+}
+program main;
+
+{$mode objfpc}{$H+}
+
+
+uses
+  portaudio,
+  sherpa_onnx,
+  dos,
+  ctypes,
+  SysUtils;
+
+var
+  Version: String;
+  EnvStr: String;
+  Status: Integer;
+  NumDevices: Integer;
+  DeviceIndex: Integer;
+  DeviceInfo: PPaDeviceInfo;
+  I: Integer;
+  Param: TPaStreamParameters;
+  Stream: PPaStream;
+  Wave: TSherpaOnnxWave;
+
+  Buffer: TSherpaOnnxCircularBuffer;
+
+function PlayCallback(
+      input: Pointer; output: Pointer;
+      frameCount: culong;
+      timeInfo: PPaStreamCallbackTimeInfo;
+      statusFlags: TPaStreamCallbackFlags;
+      userData: Pointer ): cint; cdecl;
+var
+  Samples: TSherpaOnnxSamplesArray;
+  I: Integer;
+begin
+  if Buffer.Size >= frameCount then
+    begin
+      Samples := Buffer.Get(Buffer.Head, FrameCount);
+      Buffer.Pop(FrameCount);
+    end
+  else
+    begin
+      Samples := Buffer.Get(Buffer.Head, Buffer.Size);
+      Buffer.Pop(Buffer.Size);
+      SetLength(Samples, frameCount);
+    end;
+  for I := 0 to frameCount - 1 do
+    pcfloat(output)[I] := Samples[I];
+
+  if Buffer.Size > 0 then
+    Result := paContinue
+  else
+    Result := paComplete;
+end;
+
+
+
+begin
+  Version := String(Pa_GetVersionText);
+  WriteLn('Version is ', Version);
+  Status := Pa_Initialize;
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to initialize portaudio, ', Pa_GetErrorText(Status));
+      Exit;
+    end;
+
+  NumDevices := Pa_GetDeviceCount;
+  WriteLn('Num devices: ', NumDevices);
+
+  DeviceIndex := Pa_GetDefaultOutputDevice;
+
+  if DeviceIndex = paNoDevice then
+    begin
+      WriteLn('No default output device found');
+      Pa_Terminate;
+      Exit;
+    end;
+
+  EnvStr := GetEnv('SHERPA_ONNX_MIC_DEVICE');
+  if EnvStr <> '' then
+    begin
+      DeviceIndex := StrToIntDef(EnvStr, DeviceIndex);
+      WriteLn('Use device index from environment variable SHERPA_ONNX_MIC_DEVICE: ', EnvStr);
+    end;
+
+  for I := 0 to (NumDevices - 1) do
+    begin
+      DeviceInfo := Pa_GetDeviceInfo(I);
+      if I = DeviceIndex then
+        { WriteLn(Format(' * %d %s', [I, DeviceInfo^.Name])) }
+        WriteLn(Format(' * %d %s', [I, AnsiString(DeviceInfo^.Name)]))
+      else
+        WriteLn(Format('   %d %s', [I, AnsiString(DeviceInfo^.Name)]));
+    end;
+
+  WriteLn('Use device ', DeviceIndex);
+  WriteLn(' Name ', Pa_GetDeviceInfo(DeviceIndex)^.Name);
+  WriteLn(' Max output channels ', Pa_GetDeviceInfo(DeviceIndex)^.MaxOutputChannels);
+
+  Wave := SherpaOnnxReadWave('./record.wav');
+  if Wave.Samples = nil then
+    begin
+      WriteLn('Failed to read ./record.wav');
+      Pa_Terminate;
+      Exit;
+    end;
+
+  Initialize(Param);
+  Param.Device := DeviceIndex;
+  Param.ChannelCount := 1;
+  Param.SampleFormat := paFloat32;
+  param.SuggestedLatency := Pa_GetDeviceInfo(DeviceIndex)^.DefaultHighOutputLatency;
+  param.HostApiSpecificStreamInfo := nil;
+
+  Buffer := TSherpaOnnxCircularBuffer.Create(Length(Wave.Samples));
+  Buffer.Push(Wave.Samples);
+
+  Status := Pa_OpenStream(stream, nil, @Param, Wave.SampleRate, paFramesPerBufferUnspecified, paNoFlag,
+    PPaStreamCallback(@PlayCallback), nil);
+
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to open stream, ', Pa_GetErrorText(Status));
+      Pa_Terminate;
+      Exit;
+    end;
+
+  Status := Pa_StartStream(stream);
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to start stream, ', Pa_GetErrorText(Status));
+      Pa_Terminate;
+      Exit;
+    end;
+
+  while Buffer.Size > 0 do
+    Pa_Sleep(100);  {sleep for 0.1 second }
+
+  Status := Pa_CloseStream(stream);
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to close stream, ', Pa_GetErrorText(Status));
+      Exit;
+    end;
+
+  Status := Pa_Terminate;
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to deinitialize portaudio, ', Pa_GetErrorText(Status));
+      Exit;
+    end;
+end.
+

pascal-api-examples/portaudio-test/test-record.pas

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+{ Copyright (c)  2024  Xiaomi Corporation }
+{
+This file shows how to use portaudio for recording.
+
+It records for 10 seconds and saves the audio samples to ./record.wav
+}
+program main;
+
+{$mode objfpc}
+
+uses
+  portaudio,
+  sherpa_onnx,
+  dos,
+  ctypes,
+  SysUtils;
+
+var
+  Version: String;
+  EnvStr: String;
+  Status: Integer;
+  NumDevices: Integer;
+  DeviceIndex: Integer;
+  DeviceInfo: PPaDeviceInfo;
+  I: Integer;
+  Param: TPaStreamParameters;
+  SampleRate: Double;
+  Stream: PPaStream;
+
+  Buffer: TSherpaOnnxCircularBuffer;
+  AllSamples: TSherpaOnnxSamplesArray;
+
+function RecordCallback(
+      input: Pointer; output: Pointer;
+      frameCount: culong;
+      timeInfo: PPaStreamCallbackTimeInfo;
+      statusFlags: TPaStreamCallbackFlags;
+      userData: Pointer ): cint; cdecl;
+begin
+  Buffer.Push(pcfloat(input), frameCount);
+  Result := paContinue;
+end;
+
+
+
+begin
+  Version := String(Pa_GetVersionText);
+  WriteLn('Version is ', Version);
+  Status := Pa_Initialize;
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to initialize portaudio, ', Pa_GetErrorText(Status));
+      Exit;
+    end;
+
+  NumDevices := Pa_GetDeviceCount;
+  WriteLn('Num devices: ', NumDevices);
+
+  DeviceIndex := Pa_GetDefaultInputDevice;
+
+  if DeviceIndex = paNoDevice then
+    begin
+      WriteLn('No default input device found');
+      Pa_Terminate;
+      Exit;
+    end;
+
+  EnvStr := GetEnv('SHERPA_ONNX_MIC_DEVICE');
+  if EnvStr <> '' then
+    begin
+      DeviceIndex := StrToIntDef(EnvStr, DeviceIndex);
+      WriteLn('Use device index from environment variable SHERPA_ONNX_MIC_DEVICE: ', EnvStr);
+    end;
+
+  for I := 0 to (NumDevices - 1) do
+    begin
+      DeviceInfo := Pa_GetDeviceInfo(I);
+      if I = DeviceIndex then
+        { WriteLn(Format(' * %d %s', [I, DeviceInfo^.Name])) }
+        WriteLn(Format(' * %d %s', [I, AnsiString(DeviceInfo^.Name)]))
+      else
+        WriteLn(Format('   %d %s', [I, AnsiString(DeviceInfo^.Name)]));
+    end;
+
+  WriteLn('Use device ', DeviceIndex);
+  WriteLn(' Name ', Pa_GetDeviceInfo(DeviceIndex)^.Name);
+  WriteLn(' Max input channels ', Pa_GetDeviceInfo(DeviceIndex)^.MaxInputChannels);
+
+  Initialize(Param);
+  Param.Device := DeviceIndex;
+  Param.ChannelCount := 1;
+  Param.SampleFormat := paFloat32;
+  param.SuggestedLatency := Pa_GetDeviceInfo(DeviceIndex)^.DefaultHighInputLatency;
+  param.HostApiSpecificStreamInfo := nil;
+
+  SampleRate := 48000;
+  Buffer := TSherpaOnnxCircularBuffer.Create(Round(SampleRate) * 20);
+
+  Status := Pa_OpenStream(stream, @Param, nil, SampleRate, paFramesPerBufferUnspecified, paNoFlag,
+    PPaStreamCallback(@RecordCallback), nil);
+
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to open stream, ', Pa_GetErrorText(Status));
+      Pa_Terminate;
+      Exit;
+    end;
+
+  Status := Pa_StartStream(stream);
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to start stream, ', Pa_GetErrorText(Status));
+      Pa_Terminate;
+      Exit;
+    end;
+
+  WriteLn('Please speak! It will exit after 10 seconds.');
+  Pa_Sleep(10000);  {sleep for 10 seconds }
+
+  Status := Pa_CloseStream(stream);
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to close stream, ', Pa_GetErrorText(Status));
+      Exit;
+    end;
+
+  AllSamples := Buffer.Get(0, Buffer.Size);
+
+  SherpaOnnxWriteWave('record.wav', AllSamples, Round(SampleRate));
+  WriteLn('Saved to record.wav');
+
+  Status := Pa_Terminate;
+  if Status <> paNoError then
+    begin
+      WriteLn('Failed to deinitialize portaudio, ', Pa_GetErrorText(Status));
+      Exit;
+    end;
+end.
+