Pascal API for streaming ASR (#1246)

.github/workflows/pascal.yaml

@@ -39,7 +39,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, macos-13]
+        os: [ubuntu-latest, macos-latest, macos-13, windows-latest]
 
     steps:
       - uses: actions/checkout@v4
@@ -64,10 +64,19 @@ jobs:
         run: |
           brew install fpc
           # brew install --cask lazarus
+          #
+      - name: Install Free pascal compiler (windows)
+        if: matrix.os == 'windows-latest'
+        shell: bash
+        run: |
+          choco install lazarus
+
+          ls -lh /c/lazarus/fpc/3.2.2/bin/x86_64-win64/
 
       - name: FPC info
         shell: bash
         run: |
+          export PATH=/c/lazarus/fpc/3.2.2/bin/x86_64-win64:$PATH
           which fpc
           fpc -i
 
@@ -87,6 +96,7 @@ jobs:
           cd build
 
           cmake \
+            -DCMAKE_INSTALL_PREFIX=./install \
             -D BUILD_SHARED_LIBS=ON \
             -D SHERPA_ONNX_ENABLE_BINARY=OFF \
             -D CMAKE_BUILD_TYPE=Release \
@@ -98,15 +108,55 @@ jobs:
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
 
           cd build
-          make -j2 sherpa-onnx-c-api
+          cmake --build . --target install --config Release
 
-      - name:  Run Pascal test
+          ls -lh install/lib/
+
+          if [[ ${{ matrix.os }} == 'windows-latest' ]]; then
+            cp -v install/lib/*.dll ../pascal-api-examples/read-wav
+            cp -v install/lib/*.dll ../pascal-api-examples/streaming-asr
+
+            cp -v ../sherpa-onnx/pascal-api/sherpa_onnx.pas ../pascal-api-examples/read-wav
+            cp -v ../sherpa-onnx/pascal-api/sherpa_onnx.pas ../pascal-api-examples/streaming-asr
+          fi
+
+      - name:  Run Pascal test (Read wav test)
         shell: bash
         run: |
+          export PATH=/c/lazarus/fpc/3.2.2/bin/x86_64-win64:$PATH
+
           cd ./pascal-api-examples
 
-          echo "----read-wav test-----"
           pushd read-wav
           ./run.sh
+          echo "---"
+          ls -lh
+          popd
+
+      - name:  Run Pascal test (Streaming ASR)
+        shell: bash
+        run: |
+          export PATH=/c/lazarus/fpc/3.2.2/bin/x86_64-win64:$PATH
+
+          cd ./pascal-api-examples
+
+          pushd streaming-asr
+          ./run-zipformer-transducer.sh
+          rm -rf sherpa-onnx-*
+          echo "---"
+
+          if [[ ${{ matrix.os }} != 'windows-latest' ]]; then
+            ./run-paraformer.sh
+            rm -rf sherpa-onnx-*
+            echo "---"
+
+            ./run-zipformer-ctc.sh
+            echo "---"
+
+            ./run-zipformer-ctc-hlg.sh
+            rm -rf sherpa-onnx-*
+            echo "---"
+          fi
+
           ls -lh
           popd

java-api-examples/StreamingDecodeFileCtcHLG.java

@@ -29,7 +29,7 @@ public class StreamingDecodeFileCtcHLG {
             .build();
 
     OnlineCtcFstDecoderConfig ctcFstDecoderConfig =
-        OnlineCtcFstDecoderConfig.builder().setGraph("hlg").build();
+        OnlineCtcFstDecoderConfig.builder().setGraph(hlg).build();
 
     OnlineRecognizerConfig config =
         OnlineRecognizerConfig.builder()

pascal-api-examples/README.md

@@ -0,0 +1,9 @@
+# Introduction
+
+This directory contains examples for how to use the [Object Pascal](https://en.wikipedia.org/wiki/Object_Pascal)
+APIs of [sherpa-onnx](https://github.com/k2-fsa/sherpa-onnx).
+
+|Directory| Description|
+|---------|------------|
+|[read-wav](./read-wav)|It shows how to read a wave file.|
+|[streaming-asr](./streaming-asr)| It shows how to use streaming models for speech recognition.|

pascal-api-examples/read-wav/run.sh

@@ -7,10 +7,11 @@ SHERPA_ONNX_DIR=$(cd $SCRIPT_DIR/../.. && pwd)
 
 echo "SHERPA_ONNX_DIR: $SHERPA_ONNX_DIR"
 
-if [[ ! -f ../../build/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/lib/libsherpa-onnx-c-api.so ]]; then
+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 \
@@ -18,8 +19,7 @@ if [[ ! -f ../../build/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/lib/l
     -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
     ..
 
-  make -j4 sherpa-onnx-c-api
+  cmake --build . --target install --config Release
-  ls -lh lib
   popd
 fi
 
@@ -29,10 +29,10 @@ fi
 
 fpc \
   -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
-  -Fl$SHERPA_ONNX_DIR/build/lib \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
   ./main.pas
 
-export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/lib:$LD_LIBRARY_PATH
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
-export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/lib:$DYLD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
 
 ./main

pascal-api-examples/streaming-asr/.gitignore

@@ -0,0 +1,4 @@
+zipformer_transducer
+paraformer
+zipformer_ctc
+zipformer_ctc_hlg

pascal-api-examples/streaming-asr/README.md

@@ -0,0 +1,11 @@
+# Introduction
+
+This folder contains examples about using sherpa-onnx's object pascal
+APIs with streaming models for speech recognition.
+
+|File|Description|
+|----|-----------|
+|[run-paraformer.sh](./run-paraformer.sh)|Use a streaming Paraformer model for speech recognition|
+|[run-zipformer-ctc-hlg.sh](./run-zipformer-ctc-hlg.sh)|Use a streaming Zipformer CTC model for speech recognition|
+|[run-zipformer-ctc.sh](./run-zipformer-ctc.sh)|Use a streaming Zipformer CTC model with HLG for speech recognition|
+|[run-zipformer-transducer.sh](./run-zipformer-transducer.sh)|Use a Zipformer transducer model for speech recognition|

pascal-api-examples/streaming-asr/paraformer.pas

@@ -0,0 +1,88 @@
+{ Copyright (c)  2024  Xiaomi Corporation }
+
+{
+This file shows how to use a streaming Paraformer model to decode files.
+
+You can download the model files from
+https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+}
+
+program paraformer;
+
+{$mode objfpc}
+
+uses
+  sherpa_onnx,
+  DateUtils,
+  SysUtils;
+
+var
+  Config: TSherpaOnnxOnlineRecognizerConfig;
+  Recognizer: TSherpaOnnxOnlineRecognizer;
+  Stream: TSherpaOnnxOnlineStream;
+  RecognitionResult: TSherpaOnnxOnlineRecognizerResult;
+  Wave: TSherpaOnnxWave;
+  WaveFilename: AnsiString;
+  TailPaddings: array of Single;
+
+  Start: TDateTime;
+  Stop: TDateTime;
+
+  Elapsed: Single;
+  Duration: Single;
+  RealTimeFactor: Single;
+begin
+  Initialize(Config);
+
+  {Please visit https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+  to download model files used in this file.}
+  Config.ModelConfig.Paraformer.Encoder := './sherpa-onnx-streaming-paraformer-bilingual-zh-en/encoder.int8.onnx';
+  Config.ModelConfig.Paraformer.Decoder := './sherpa-onnx-streaming-paraformer-bilingual-zh-en/decoder.int8.onnx';
+  Config.ModelConfig.Tokens := './sherpa-onnx-streaming-paraformer-bilingual-zh-en/tokens.txt';
+
+  Config.ModelConfig.Provider := 'cpu';
+  Config.ModelConfig.NumThreads := 1;
+  Config.ModelConfig.Debug := False;
+
+  WaveFilename := './sherpa-onnx-streaming-paraformer-bilingual-zh-en/test_wavs/2.wav';
+
+  Wave := SherpaOnnxReadWave(WaveFilename);
+
+  Recognizer := TSherpaOnnxOnlineRecognizer.Create(Config);
+
+  Start := Now;
+
+  Stream := Recognizer.CreateStream();
+
+  Stream.AcceptWaveform(Wave.Samples, Wave.SampleRate);
+
+  SetLength(TailPaddings, Round(Wave.SampleRate * 0.5)); {0.5 seconds of padding}
+  Stream.AcceptWaveform(TailPaddings, Wave.SampleRate);
+
+  Stream.InputFinished();
+
+  while Recognizer.IsReady(Stream) do
+    Recognizer.Decode(Stream);
+
+  RecognitionResult := Recognizer.GetResult(Stream);
+
+  Stop := Now;
+
+  Elapsed := MilliSecondsBetween(Stop, Start) / 1000;
+  Duration := Length(Wave.Samples) / Wave.SampleRate;
+  RealTimeFactor := Elapsed / Duration;
+
+  WriteLn(RecognitionResult.ToString);
+  WriteLn(Format('NumThreads %d', [Config.ModelConfig.NumThreads]));
+  WriteLn(Format('Elapsed %.3f s', [Elapsed]));
+  WriteLn(Format('Wave duration %.3f s', [Duration]));
+  WriteLn(Format('RTF = %.3f/%.3f = %.3f', [Elapsed, Duration, RealTimeFactor]));
+
+  {Free resources to avoid memory leak.
+
+  Note: You don't need to invoke them for this simple script.
+  However, you have to invoke them in your own large/complex project.
+  }
+  FreeAndNil(Stream);
+  FreeAndNil(Recognizer);
+end.

pascal-api-examples/streaming-asr/run-paraformer.sh

@@ -0,0 +1,42 @@
+#!/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: $SHERPA_ONNX_DIR"
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/install/lib/libsherpa-onnx-c-api.so && ! -f ../../build/install/lib/sherpa-onnx-c-api.dll ]]; then
+  mkdir -p ../../build
+  pushd ../../build
+  cmake \
+    -DCMAKE_INSTALL_PREFIX=./install \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    ..
+
+  cmake --build . --target install --config Release
+  ls -lh lib
+  popd
+fi
+
+
+if [ ! -f ./sherpa-onnx-streaming-paraformer-bilingual-zh-en/tokens.txt ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+  tar xvf sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+  rm sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+fi
+
+fpc \
+  -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
+  ./paraformer.pas
+
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
+
+./paraformer

pascal-api-examples/streaming-asr/run-zipformer-ctc-hlg.sh

@@ -0,0 +1,41 @@
+#!/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: $SHERPA_ONNX_DIR"
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/install/lib/libsherpa-onnx-c-api.so && ! -f ../../build/install/lib/sherpa-onnx-c-api.dll ]]; then
+  mkdir -p ../../build
+  pushd ../../build
+  cmake \
+    -DCMAKE_INSTALL_PREFIX=./install \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    ..
+
+  cmake --build . --target install --config Release
+  ls -lh lib
+  popd
+fi
+
+if [ ! -f ./sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+  tar xvf sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+  rm sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+fi
+
+fpc \
+  -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
+  ./zipformer_ctc_hlg.pas
+
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
+
+./zipformer_ctc_hlg

pascal-api-examples/streaming-asr/run-zipformer-ctc.sh

@@ -0,0 +1,41 @@
+#!/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: $SHERPA_ONNX_DIR"
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/install/lib/libsherpa-onnx-c-api.so && ! -f ../../build/install/lib/sherpa-onnx-c-api.dll ]]; then
+  mkdir -p ../../build
+  pushd ../../build
+  cmake \
+    -DCMAKE_INSTALL_PREFIX=./install \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    ..
+
+  cmake --build . --target install --config Release
+  ls -lh lib
+  popd
+fi
+
+if [ ! -f ./sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+  tar xvf sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+  rm sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18.tar.bz2
+fi
+
+fpc \
+  -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
+  ./zipformer_ctc.pas
+
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
+
+./zipformer_ctc

pascal-api-examples/streaming-asr/run-zipformer-transducer.sh

@@ -0,0 +1,42 @@
+#!/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: $SHERPA_ONNX_DIR"
+
+if [[ ! -f ../../build/install/lib/libsherpa-onnx-c-api.dylib  && ! -f ../../build/install/lib/libsherpa-onnx-c-api.so && ! -f ../../build/install/lib/sherpa-onnx-c-api.dll ]]; then
+  mkdir -p ../../build
+  pushd ../../build
+  cmake \
+    -DCMAKE_INSTALL_PREFIX=./install \
+    -DSHERPA_ONNX_ENABLE_PYTHON=OFF \
+    -DSHERPA_ONNX_ENABLE_TESTS=OFF \
+    -DSHERPA_ONNX_ENABLE_CHECK=OFF \
+    -DBUILD_SHARED_LIBS=ON \
+    -DSHERPA_ONNX_ENABLE_PORTAUDIO=OFF \
+    ..
+
+  cmake --build . --target install --config Release
+  ls -lh lib
+  popd
+fi
+
+if [ ! -f ./sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/tokens.txt ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+  tar xvf sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+  rm sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20.tar.bz2
+fi
+
+
+fpc \
+  -Fu$SHERPA_ONNX_DIR/sherpa-onnx/pascal-api \
+  -Fl$SHERPA_ONNX_DIR/build/install/lib \
+  ./zipformer_transducer.pas
+
+export LD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$LD_LIBRARY_PATH
+export DYLD_LIBRARY_PATH=$SHERPA_ONNX_DIR/build/install/lib:$DYLD_LIBRARY_PATH
+
+./zipformer_transducer

pascal-api-examples/streaming-asr/zipformer_ctc.pas

@@ -0,0 +1,87 @@
+{ Copyright (c)  2024  Xiaomi Corporation }
+
+{
+This file shows how to use a streaming Zipformer CTC model
+to decode files.
+
+You can download the model files from
+https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+}
+
+program zipformer_ctc;
+
+{$mode objfpc}
+
+uses
+  sherpa_onnx,
+  DateUtils,
+  SysUtils;
+
+var
+  Config: TSherpaOnnxOnlineRecognizerConfig;
+  Recognizer: TSherpaOnnxOnlineRecognizer;
+  Stream: TSherpaOnnxOnlineStream;
+  RecognitionResult: TSherpaOnnxOnlineRecognizerResult;
+  Wave: TSherpaOnnxWave;
+  WaveFilename: AnsiString;
+  TailPaddings: array of Single;
+
+  Start: TDateTime;
+  Stop: TDateTime;
+
+  Elapsed: Single;
+  Duration: Single;
+  RealTimeFactor: Single;
+begin
+  Initialize(Config);
+
+  {Please visit https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+  to download model files used in this file.}
+  Config.ModelConfig.Zipformer2Ctc.Model := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/ctc-epoch-30-avg-3-chunk-16-left-128.int8.onnx';
+  Config.ModelConfig.Tokens := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt';
+  Config.ModelConfig.Provider := 'cpu';
+  Config.ModelConfig.NumThreads := 1;
+  Config.ModelConfig.Debug := False;
+
+  WaveFilename := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/test_wavs/8k.wav';
+
+  Wave := SherpaOnnxReadWave(WaveFilename);
+
+  Recognizer := TSherpaOnnxOnlineRecognizer.Create(Config);
+
+  Start := Now;
+
+  Stream := Recognizer.CreateStream();
+
+  Stream.AcceptWaveform(Wave.Samples, Wave.SampleRate);
+
+  SetLength(TailPaddings, Round(Wave.SampleRate * 0.5)); {0.5 seconds of padding}
+  Stream.AcceptWaveform(TailPaddings, Wave.SampleRate);
+
+  Stream.InputFinished();
+
+  while Recognizer.IsReady(Stream) do
+    Recognizer.Decode(Stream);
+
+  RecognitionResult := Recognizer.GetResult(Stream);
+
+  Stop := Now;
+
+  Elapsed := MilliSecondsBetween(Stop, Start) / 1000;
+  Duration := Length(Wave.Samples) / Wave.SampleRate;
+  RealTimeFactor := Elapsed / Duration;
+
+  WriteLn(RecognitionResult.ToString);
+  WriteLn(Format('NumThreads %d', [Config.ModelConfig.NumThreads]));
+  WriteLn(Format('Elapsed %.3f s', [Elapsed]));
+  WriteLn(Format('Wave duration %.3f s', [Duration]));
+  WriteLn(Format('RTF = %.3f/%.3f = %.3f', [Elapsed, Duration, RealTimeFactor]));
+
+  {Free resources to avoid memory leak.
+
+  Note: You don't need to invoke them for this simple script.
+  However, you have to invoke them in your own large/complex project.
+  }
+  FreeAndNil(Stream);
+  FreeAndNil(Recognizer);
+end.

pascal-api-examples/streaming-asr/zipformer_ctc_hlg.pas

@@ -0,0 +1,88 @@
+{ Copyright (c)  2024  Xiaomi Corporation }
+
+{
+This file shows how to use a streaming Zipformer CTC model
+with HLG to decode files.
+
+You can download the model files from
+https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+}
+
+program zipformer_ctc_hlg;
+
+{$mode objfpc}
+
+uses
+  sherpa_onnx,
+  DateUtils,
+  SysUtils;
+
+var
+  Config: TSherpaOnnxOnlineRecognizerConfig;
+  Recognizer: TSherpaOnnxOnlineRecognizer;
+  Stream: TSherpaOnnxOnlineStream;
+  RecognitionResult: TSherpaOnnxOnlineRecognizerResult;
+  Wave: TSherpaOnnxWave;
+  WaveFilename: AnsiString;
+  TailPaddings: array of Single;
+
+  Start: TDateTime;
+  Stop: TDateTime;
+
+  Elapsed: Single;
+  Duration: Single;
+  RealTimeFactor: Single;
+begin
+  Initialize(Config);
+
+  {Please visit https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+  to download model files used in this file.}
+  Config.ModelConfig.Zipformer2Ctc.Model := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/ctc-epoch-30-avg-3-chunk-16-left-128.int8.onnx';
+  Config.ModelConfig.Tokens := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/tokens.txt';
+  Config.ModelConfig.Provider := 'cpu';
+  Config.ModelConfig.NumThreads := 1;
+  Config.ModelConfig.Debug := True;
+  Config.CtcFstDecoderConfig.Graph := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/HLG.fst';
+
+  WaveFilename := './sherpa-onnx-streaming-zipformer-ctc-small-2024-03-18/test_wavs/8k.wav';
+
+  Wave := SherpaOnnxReadWave(WaveFilename);
+
+  Recognizer := TSherpaOnnxOnlineRecognizer.Create(Config);
+
+  Start := Now;
+
+  Stream := Recognizer.CreateStream();
+
+  Stream.AcceptWaveform(Wave.Samples, Wave.SampleRate);
+
+  SetLength(TailPaddings, Round(Wave.SampleRate * 0.5)); {0.5 seconds of padding}
+  Stream.AcceptWaveform(TailPaddings, Wave.SampleRate);
+
+  Stream.InputFinished();
+
+  while Recognizer.IsReady(Stream) do
+    Recognizer.Decode(Stream);
+
+  RecognitionResult := Recognizer.GetResult(Stream);
+
+  Stop := Now;
+
+  Elapsed := MilliSecondsBetween(Stop, Start) / 1000;
+  Duration := Length(Wave.Samples) / Wave.SampleRate;
+  RealTimeFactor := Elapsed / Duration;
+
+  WriteLn(RecognitionResult.ToString);
+  WriteLn(Format('NumThreads %d', [Config.ModelConfig.NumThreads]));
+  WriteLn(Format('Elapsed %.3f s', [Elapsed]));
+  WriteLn(Format('Wave duration %.3f s', [Duration]));
+  WriteLn(Format('RTF = %.3f/%.3f = %.3f', [Elapsed, Duration, RealTimeFactor]));
+
+  {Free resources to avoid memory leak.
+
+  Note: You don't need to invoke them for this simple script.
+  However, you have to invoke them in your own large/complex project.
+  }
+  FreeAndNil(Stream);
+  FreeAndNil(Recognizer);
+end.

pascal-api-examples/streaming-asr/zipformer_transducer.pas

@@ -0,0 +1,89 @@
+{ Copyright (c)  2024  Xiaomi Corporation }
+
+{
+This file shows how to use a streaming Zipformer transducer
+to decode files.
+
+You can download the model files from
+https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+}
+
+program zipformer_transducer;
+
+{$mode objfpc}
+
+uses
+  sherpa_onnx,
+  DateUtils,
+  SysUtils;
+
+var
+  Config: TSherpaOnnxOnlineRecognizerConfig;
+  Recognizer: TSherpaOnnxOnlineRecognizer;
+  Stream: TSherpaOnnxOnlineStream;
+  RecognitionResult: TSherpaOnnxOnlineRecognizerResult;
+  Wave: TSherpaOnnxWave;
+  WaveFilename: AnsiString;
+  TailPaddings: array of Single;
+
+  Start: TDateTime;
+  Stop: TDateTime;
+
+  Elapsed: Single;
+  Duration: Single;
+  RealTimeFactor: Single;
+begin
+  Initialize(Config);
+
+  {Please visit https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
+  to download model files used in this file.}
+  Config.ModelConfig.Transducer.Encoder := './sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/encoder-epoch-99-avg-1.int8.onnx';
+  Config.ModelConfig.Transducer.Decoder := './sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/decoder-epoch-99-avg-1.onnx';
+  Config.ModelConfig.Transducer.Joiner := './sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/joiner-epoch-99-avg-1.int8.onnx';
+  Config.ModelConfig.Tokens := './sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/tokens.txt';
+  Config.ModelConfig.Provider := 'cpu';
+  Config.ModelConfig.NumThreads := 1;
+  Config.ModelConfig.Debug := False;
+
+  WaveFilename := './sherpa-onnx-streaming-zipformer-bilingual-zh-en-2023-02-20/test_wavs/0.wav';
+
+  Wave := SherpaOnnxReadWave(WaveFilename);
+
+  Recognizer := TSherpaOnnxOnlineRecognizer.Create(Config);
+
+  Start := Now;
+
+  Stream := Recognizer.CreateStream();
+
+  Stream.AcceptWaveform(Wave.Samples, Wave.SampleRate);
+
+  SetLength(TailPaddings, Round(Wave.SampleRate * 0.5)); {0.5 seconds of padding}
+  Stream.AcceptWaveform(TailPaddings, Wave.SampleRate);
+
+  Stream.InputFinished();
+
+  while Recognizer.IsReady(Stream) do
+    Recognizer.Decode(Stream);
+
+  RecognitionResult := Recognizer.GetResult(Stream);
+
+  Stop := Now;
+
+  Elapsed := MilliSecondsBetween(Stop, Start) / 1000;
+  Duration := Length(Wave.Samples) / Wave.SampleRate;
+  RealTimeFactor := Elapsed / Duration;
+
+  WriteLn(RecognitionResult.ToString);
+  WriteLn(Format('NumThreads %d', [Config.ModelConfig.NumThreads]));
+  WriteLn(Format('Elapsed %.3f s', [Elapsed]));
+  WriteLn(Format('Wave duration %.3f s', [Duration]));
+  WriteLn(Format('RTF = %.3f/%.3f = %.3f', [Elapsed, Duration, RealTimeFactor]));
+
+  {Free resources to avoid memory leak.
+
+  Note: You don't need to invoke them for this simple script.
+  However, you have to invoke them in your own large/complex project.
+  }
+  FreeAndNil(Stream);
+  FreeAndNil(Recognizer);
+end.

sherpa-onnx/c-api/c-api.cc

@@ -75,17 +75,31 @@ SherpaOnnxOnlineRecognizer *SherpaOnnxCreateOnlineRecognizer(
       SHERPA_ONNX_OR(config->model_config.num_threads, 1);
   recognizer_config.model_config.provider_config.provider =
       SHERPA_ONNX_OR(config->model_config.provider, "cpu");
+
+  if (recognizer_config.model_config.provider_config.provider.empty()) {
+    recognizer_config.model_config.provider_config.provider = "cpu";
+  }
+
   recognizer_config.model_config.model_type =
       SHERPA_ONNX_OR(config->model_config.model_type, "");
   recognizer_config.model_config.debug =
       SHERPA_ONNX_OR(config->model_config.debug, 0);
   recognizer_config.model_config.modeling_unit =
       SHERPA_ONNX_OR(config->model_config.modeling_unit, "cjkchar");
+
+  if (recognizer_config.model_config.modeling_unit.empty()) {
+    recognizer_config.model_config.modeling_unit = "cjkchar";
+  }
+
   recognizer_config.model_config.bpe_vocab =
       SHERPA_ONNX_OR(config->model_config.bpe_vocab, "");
 
   recognizer_config.decoding_method =
       SHERPA_ONNX_OR(config->decoding_method, "greedy_search");
+  if (recognizer_config.decoding_method.empty()) {
+    recognizer_config.decoding_method = "greedy_search";
+  }
+
   recognizer_config.max_active_paths =
       SHERPA_ONNX_OR(config->max_active_paths, 4);
 
@@ -391,10 +405,19 @@ sherpa_onnx::OfflineRecognizerConfig convertConfig(
       SHERPA_ONNX_OR(config->model_config.debug, 0);
   recognizer_config.model_config.provider =
       SHERPA_ONNX_OR(config->model_config.provider, "cpu");
+  if (recognizer_config.model_config.provider.empty()) {
+    recognizer_config.model_config.provider = "cpu";
+  }
+
   recognizer_config.model_config.model_type =
       SHERPA_ONNX_OR(config->model_config.model_type, "");
   recognizer_config.model_config.modeling_unit =
       SHERPA_ONNX_OR(config->model_config.modeling_unit, "cjkchar");
+
+  if (recognizer_config.model_config.modeling_unit.empty()) {
+    recognizer_config.model_config.modeling_unit = "cjkchar";
+  }
+
   recognizer_config.model_config.bpe_vocab =
       SHERPA_ONNX_OR(config->model_config.bpe_vocab, "");
 
@@ -620,6 +643,10 @@ SherpaOnnxKeywordSpotter *SherpaOnnxCreateKeywordSpotter(
       SHERPA_ONNX_OR(config->model_config.num_threads, 1);
   spotter_config.model_config.provider_config.provider =
       SHERPA_ONNX_OR(config->model_config.provider, "cpu");
+  if (spotter_config.model_config.provider_config.provider.empty()) {
+    spotter_config.model_config.provider_config.provider = "cpu";
+  }
+
   spotter_config.model_config.model_type =
       SHERPA_ONNX_OR(config->model_config.model_type, "");
   spotter_config.model_config.debug =
@@ -855,6 +882,10 @@ SherpaOnnxVoiceActivityDetector *SherpaOnnxCreateVoiceActivityDetector(
   vad_config.sample_rate = SHERPA_ONNX_OR(config->sample_rate, 16000);
   vad_config.num_threads = SHERPA_ONNX_OR(config->num_threads, 1);
   vad_config.provider = SHERPA_ONNX_OR(config->provider, "cpu");
+  if (vad_config.provider.empty()) {
+    vad_config.provider = "cpu";
+  }
+
   vad_config.debug = SHERPA_ONNX_OR(config->debug, false);
 
   if (vad_config.debug) {
@@ -956,6 +987,10 @@ SherpaOnnxOfflineTts *SherpaOnnxCreateOfflineTts(
   tts_config.model.num_threads = SHERPA_ONNX_OR(config->model.num_threads, 1);
   tts_config.model.debug = config->model.debug;
   tts_config.model.provider = SHERPA_ONNX_OR(config->model.provider, "cpu");
+  if (tts_config.model.provider.empty()) {
+    tts_config.model.provider = "cpu";
+  }
+
   tts_config.rule_fsts = SHERPA_ONNX_OR(config->rule_fsts, "");
   tts_config.rule_fars = SHERPA_ONNX_OR(config->rule_fars, "");
   tts_config.max_num_sentences = SHERPA_ONNX_OR(config->max_num_sentences, 2);
@@ -1101,6 +1136,9 @@ SherpaOnnxCreateSpokenLanguageIdentification(
   slid_config.num_threads = SHERPA_ONNX_OR(config->num_threads, 1);
   slid_config.debug = config->debug;
   slid_config.provider = SHERPA_ONNX_OR(config->provider, "cpu");
+  if (slid_config.provider.empty()) {
+    slid_config.provider = "cpu";
+  }
 
   if (slid_config.debug) {
     SHERPA_ONNX_LOGE("%s\n", slid_config.ToString().c_str());
@@ -1167,6 +1205,9 @@ SherpaOnnxCreateSpeakerEmbeddingExtractor(
   c.num_threads = SHERPA_ONNX_OR(config->num_threads, 1);
   c.debug = SHERPA_ONNX_OR(config->debug, 0);
   c.provider = SHERPA_ONNX_OR(config->provider, "cpu");
+  if (c.provider.empty()) {
+    c.provider = "cpu";
+  }
 
   if (config->debug) {
     SHERPA_ONNX_LOGE("%s\n", c.ToString().c_str());
@@ -1401,6 +1442,10 @@ const SherpaOnnxAudioTagging *SherpaOnnxCreateAudioTagging(
   ac.model.num_threads = SHERPA_ONNX_OR(config->model.num_threads, 1);
   ac.model.debug = config->model.debug;
   ac.model.provider = SHERPA_ONNX_OR(config->model.provider, "cpu");
+  if (ac.model.provider.empty()) {
+    ac.model.provider = "cpu";
+  }
+
   ac.labels = SHERPA_ONNX_OR(config->labels, "");
   ac.top_k = SHERPA_ONNX_OR(config->top_k, 5);
 
@@ -1487,6 +1532,9 @@ const SherpaOnnxOfflinePunctuation *SherpaOnnxCreateOfflinePunctuation(
   c.model.num_threads = SHERPA_ONNX_OR(config->model.num_threads, 1);
   c.model.debug = config->model.debug;
   c.model.provider = SHERPA_ONNX_OR(config->model.provider, "cpu");
+  if (c.model.provider.empty()) {
+    c.model.provider = "cpu";
+  }
 
   if (c.model.debug) {
     SHERPA_ONNX_LOGE("%s\n", c.ToString().c_str());

sherpa-onnx/pascal-api/sherpa_onnx.pas

@@ -4,6 +4,9 @@ unit sherpa_onnx;
 
 {$mode objfpc}
 
+{$modeSwitch advancedRecords} { to support records with methods }
+(* {$LongStrings ON} *)
+
 interface
 
 type
@@ -12,15 +15,117 @@ type
     SampleRate: Integer;
   end;
 
+  TSherpaOnnxOnlineTransducerModelConfig = record
+    Encoder: AnsiString;
+    Decoder: AnsiString;
+    Joiner: AnsiString;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineParaformerModelConfig = record
+    Encoder: AnsiString;
+    Decoder: AnsiString;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineZipformer2CtcModelConfig = record
+    Model: AnsiString;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineModelConfig = record
+    Transducer: TSherpaOnnxOnlineTransducerModelConfig;
+    Paraformer: TSherpaOnnxOnlineParaformerModelConfig;
+    Zipformer2Ctc: TSherpaOnnxOnlineZipformer2CtcModelConfig;
+    Tokens: AnsiString;
+    NumThreads: Integer;
+    Provider: AnsiString;
+    Debug: Boolean;
+    ModelType: AnsiString;
+    ModelingUnit: AnsiString;
+    BpeVocab: AnsiString;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxFeatureConfig = record
+    SampleRate: Integer;
+    FeatureDim: Integer;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineCtcFstDecoderConfig = record
+    Graph: AnsiString;
+    MaxActive: Integer;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineRecognizerConfig = record
+    FeatConfig: TSherpaOnnxFeatureConfig;
+    ModelConfig: TSherpaOnnxOnlineModelConfig;
+    DecodingMethod: AnsiString;
+    MaxActivePaths: Integer;
+    EnableEndpoint: Boolean;
+    Rule1MinTrailingSilence: Single;
+    Rule2MinTrailingSilence: Single;
+    Rule3MinUtteranceLength: Single;
+    HotwordsFile: AnsiString;
+    HotwordsScore: Single;
+    CtcFstDecoderConfig: TSherpaOnnxOnlineCtcFstDecoderConfig;
+    RuleFsts: AnsiString;
+    RuleFars: AnsiString;
+    BlankPenalty: Single;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineRecognizerResult = record
+    Text: AnsiString;
+    Tokens: array of AnsiString;
+    Timestamps: array of Single;
+    function ToString: AnsiString;
+  end;
+
+  TSherpaOnnxOnlineStream = class
+  private
+   Handle: Pointer;
+  public
+    constructor Create(P: Pointer);
+    destructor Destroy; override;
+    procedure AcceptWaveform(Samples: array of Single; SampleRate: Integer);
+    procedure InputFinished;
+  end;
+
+  TSherpaOnnxOnlineRecognizer = class
+  private
+   Handle: Pointer;
+  public
+    constructor Create(Config: TSherpaOnnxOnlineRecognizerConfig);
+    destructor Destroy; override;
+
+    function CreateStream: TSherpaOnnxOnlineStream; overload;
+    function CreateStream(Hotwords: AnsiString): TSherpaOnnxOnlineStream; overload;
+    function IsReady(Stream: TSherpaOnnxOnlineStream): Boolean;
+    procedure Decode(Stream: TSherpaOnnxOnlineStream);
+    procedure Reset(Stream: TSherpaOnnxOnlineStream);
+    function IsEndpoint(Stream: TSherpaOnnxOnlineStream): Boolean;
+    function GetResult(Stream: TSherpaOnnxOnlineStream): TSherpaOnnxOnlineRecognizerResult;
+  end;
+
 { It supports reading a single channel wave with 16-bit encoded samples.
   Samples are normalized to the range [-1, 1].
 }
-function SherpaOnnxReadWave(Filename: string): TSherpaOnnxWave;
+function SherpaOnnxReadWave(Filename: AnsiString): TSherpaOnnxWave;
 
 implementation
 
 uses
-  ctypes;
+  ctypes,
+  fpjson,
+    { See
+      - https://wiki.freepascal.org/fcl-json
+      - https://www.freepascal.org/daily/doc/fcl/fpjson/getjson.html
+    }
+  jsonparser,
+  SysUtils;
 
 const
   {See https://www.freepascal.org/docs-html/prog/progap7.html}
@@ -47,31 +152,383 @@ type
 
   PSherpaOnnxWave = ^SherpaOnnxWave;
 
+  SherpaOnnxOnlineTransducerModelConfig = record
+    Encoder: PAnsiChar;
+    Decoder: PAnsiChar;
+    Joiner: PAnsiChar;
+  end;
+  SherpaOnnxOnlineParaformerModelConfig = record
+    Encoder: PAnsiChar;
+    Decoder: PAnsiChar;
+  end;
+  SherpaOnnxOnlineZipformer2CtcModelConfig = record
+    Model: PAnsiChar;
+  end;
+
+  SherpaOnnxOnlineModelConfig= record
+    Transducer: SherpaOnnxOnlineTransducerModelConfig;
+    Paraformer: SherpaOnnxOnlineParaformerModelConfig;
+    Zipformer2Ctc: SherpaOnnxOnlineZipformer2CtcModelConfig;
+    Tokens: PAnsiChar;
+    NumThreads: cint32;
+    Provider: PAnsiChar;
+    Debug: cint32;
+    ModelType: PAnsiChar;
+    ModelingUnit: PAnsiChar;
+    BpeVocab: PAnsiChar;
+  end;
+  SherpaOnnxFeatureConfig = record
+    SampleRate: cint32;
+    FeatureDim: cint32;
+  end;
+  SherpaOnnxOnlineCtcFstDecoderConfig = record
+    Graph: PAnsiChar;
+    MaxActive: cint32;
+  end;
+  SherpaOnnxOnlineRecognizerConfig = record
+    FeatConfig: SherpaOnnxFeatureConfig;
+    ModelConfig: SherpaOnnxOnlineModelConfig;
+    DecodingMethod: PAnsiChar;
+    MaxActivePaths: cint32;
+    EnableEndpoint: cint32;
+    Rule1MinTrailingSilence: Single;
+    Rule2MinTrailingSilence: Single;
+    Rule3MinUtteranceLength: Single;
+    HotwordsFile: PAnsiChar;
+    HotwordsScore: Single;
+    CtcFstDecoderConfig: SherpaOnnxOnlineCtcFstDecoderConfig;
+    RuleFsts: PAnsiChar;
+    RuleFars: PAnsiChar;
+    BlankPenalty: Single;
+  end;
+
+  PSherpaOnnxOnlineRecognizerConfig = ^SherpaOnnxOnlineRecognizerConfig;
+
+function SherpaOnnxCreateOnlineRecognizer(Config: PSherpaOnnxOnlineRecognizerConfig): Pointer; cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxDestroyOnlineRecognizer(Recognizer: Pointer); cdecl;
+  external SherpaOnnxLibName;
+
+function SherpaOnnxCreateOnlineStream(Recognizer: Pointer): Pointer; cdecl;
+  external SherpaOnnxLibName;
+
+function SherpaOnnxCreateOnlineStreamWithHotwords(Recognizer: Pointer; Hotwords: PAnsiChar): Pointer; cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxDestroyOnlineStream(Recognizer: Pointer); cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxOnlineStreamAcceptWaveform(Stream: Pointer;
+  SampleRate: cint32; Samples: pcfloat; N: cint32 ); cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxOnlineStreamInputFinished(Stream: Pointer); cdecl;
+  external SherpaOnnxLibName;
+
+function SherpaOnnxIsOnlineStreamReady(Recognizer: Pointer; Stream: Pointer): cint32; cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxDecodeOnlineStream(Recognizer: Pointer; Stream: Pointer); cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxOnlineStreamReset(Recognizer: Pointer; Stream: Pointer); cdecl;
+  external SherpaOnnxLibName;
+
+function SherpaOnnxOnlineStreamIsEndpoint(Recognizer: Pointer; Stream: Pointer): cint32; cdecl;
+  external SherpaOnnxLibName;
+
+function SherpaOnnxGetOnlineStreamResultAsJson(Recognizer: Pointer; Stream: Pointer): PAnsiChar; cdecl;
+  external SherpaOnnxLibName;
+
+procedure SherpaOnnxDestroyOnlineStreamResultJson(PJson: PAnsiChar); cdecl;
+  external SherpaOnnxLibName;
+
 function SherpaOnnxReadWaveWrapper(Filename: PAnsiChar): PSherpaOnnxWave; cdecl;
   external SherpaOnnxLibName name 'SherpaOnnxReadWave';
 
 procedure SherpaOnnxFreeWaveWrapper(P: PSherpaOnnxWave); cdecl;
   external SherpaOnnxLibName name 'SherpaOnnxFreeWave';
 
-function SherpaOnnxReadWave(Filename: string): TSherpaOnnxWave;
+function SherpaOnnxReadWave(Filename: AnsiString): TSherpaOnnxWave;
 var
-  AnsiFilename: AnsiString;
   PFilename: PAnsiChar;
   PWave: PSherpaOnnxWave;
   I: Integer;
 begin
-  AnsiFilename := Filename;
+  PFilename := PAnsiChar(Filename);
-  PFilename := PAnsiChar(AnsiFilename);
   PWave := SherpaOnnxReadWaveWrapper(PFilename);
 
+  Result.Samples := nil;
   SetLength(Result.Samples, PWave^.NumSamples);
 
   Result.SampleRate := PWave^.SampleRate;
 
   for I := Low(Result.Samples) to High(Result.Samples) do
-    Result.Samples[i] := PWave^.Samples[i];
+    Result.Samples[I] := PWave^.Samples[I];
 
   SherpaOnnxFreeWaveWrapper(PWave);
 end;
 
+function TSherpaOnnxOnlineTransducerModelConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxOnlineTransducerModelConfig(Encoder := %s, Decoder := %s, Joiner := %s)',
+  [Self.Encoder, Self.Decoder, Self.Joiner]);
+end;
+
+function TSherpaOnnxOnlineParaformerModelConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxOnlineParaformerModelConfig(Encoder := %s, Decoder := %s)',
+  [Self.Encoder, Self.Decoder]);
+end;
+
+function TSherpaOnnxOnlineZipformer2CtcModelConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxOnlineZipformer2CtcModelConfig(Model := %s)',
+  [Self.Model]);
+end;
+
+function TSherpaOnnxOnlineModelConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxOnlineModelConfig(Transducer := %s, ' +
+    'Paraformer := %s,' +
+    'Zipformer2Ctc := %s, ' +
+    'Tokens := %s, ' +
+    'NumThreads := %d, ' +
+    'Provider := %s, ' +
+    'Debug := %s, ' +
+    'ModelType := %s, ' +
+    'ModelingUnit := %s, ' +
+    'BpeVocab := %s)'
+    ,
+  [Self.Transducer.ToString, Self.Paraformer.ToString,
+   Self.Zipformer2Ctc.ToString, Self.Tokens,
+   Self.NumThreads, Self.Provider, Self.Debug.ToString,
+   Self.ModelType, Self.ModelingUnit, Self.BpeVocab
+  ]);
+end;
+
+function TSherpaOnnxFeatureConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxFeatureConfig(SampleRate := %d, FeatureDim := %d)',
+    [Self.SampleRate, Self.FeatureDim]);
+end;
+
+function TSherpaOnnxOnlineCtcFstDecoderConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxOnlineCtcFstDecoderConfig(Graph := %s, MaxActive := %d)',
+  [Self.Graph, Self.MaxActive]);
+end;
+
+function TSherpaOnnxOnlineRecognizerConfig.ToString: AnsiString;
+begin
+  Result := Format('TSherpaOnnxOnlineRecognizerConfig(FeatConfg := %s, ' +
+    'ModelConfig := %s, ' +
+    'DecodingMethod := %s, ' +
+    'MaxActivePaths := %d, ' +
+    'EnableEndpoint := %s, ' +
+    'Rule1MinTrailingSilence := %.1f, ' +
+    'Rule2MinTrailingSilence := %.1f, ' +
+    'Rule3MinUtteranceLength := %.1f, ' +
+    'HotwordsFile := %s, ' +
+    'HotwordsScore := %.1f, ' +
+    'CtcFstDecoderConfig := %s, ' +
+    'RuleFsts := %s, ' +
+    'RuleFars := %s, ' +
+    'BlankPenalty := %.1f' +
+    ')'
+    ,
+    [Self.FeatConfig.ToString, Self.ModelConfig.ToString,
+     Self.DecodingMethod, Self.MaxActivePaths, Self.EnableEndpoint.ToString,
+     Self.Rule1MinTrailingSilence, Self.Rule2MinTrailingSilence,
+     Self.Rule3MinUtteranceLength, Self.HotwordsFile, Self.HotwordsScore,
+     Self.CtcFstDecoderConfig.ToString, Self.RuleFsts, Self.RuleFars,
+     Self.BlankPenalty
+    ]);
+end;
+
+function TSherpaOnnxOnlineRecognizerResult.ToString: AnsiString;
+var
+  TokensStr: AnsiString;
+  S: AnsiString;
+  TimestampStr: AnsiString;
+  T: Single;
+  Sep: AnsiString;
+begin
+  TokensStr := '[';
+  Sep := '';
+  for S in Self.Tokens do
+  begin
+    TokensStr := TokensStr + Sep + S;
+    Sep := ', ';
+  end;
+  TokensStr := TokensStr + ']';
+
+  TimestampStr := '[';
+  Sep := '';
+  for T in Self.Timestamps do
+  begin
+    TimestampStr := TimestampStr + Sep + Format('%.2f', [T]);
+    Sep := ', ';
+  end;
+  TimestampStr := TimestampStr + ']';
+
+  Result := Format('TSherpaOnnxOnlineRecognizerResult(Text := %s, ' +
+    'Tokens := %s, ' +
+    'Timestamps := %s, ' +
+    ')',
+    [Self.Text, TokensStr, TimestampStr]);
+end;
+
+constructor TSherpaOnnxOnlineRecognizer.Create(Config: TSherpaOnnxOnlineRecognizerConfig);
+var
+  C: SherpaOnnxOnlineRecognizerConfig;
+begin
+  Initialize(C);
+
+  C.FeatConfig.SampleRate := Config.FeatConfig.SampleRate;
+  C.FeatConfig.FeatureDim := Config.FeatConfig.FeatureDim;
+
+  C.ModelConfig.Transducer.Encoder := PAnsiChar(Config.ModelConfig.Transducer.Encoder);
+  C.ModelConfig.Transducer.Decoder := PAnsiChar(Config.ModelConfig.Transducer.Decoder);
+  C.ModelConfig.Transducer.Joiner := PAnsiChar(Config.ModelConfig.Transducer.Joiner);
+
+  C.ModelConfig.Paraformer.Encoder := PAnsiChar(Config.ModelConfig.Paraformer.Encoder);
+  C.ModelConfig.Paraformer.Decoder := PAnsiChar(Config.ModelConfig.Paraformer.Decoder);
+
+  C.ModelConfig.Zipformer2Ctc.Model := PAnsiChar(Config.ModelConfig.Zipformer2Ctc.Model);
+
+  C.ModelConfig.Tokens := PAnsiChar(Config.ModelConfig.Tokens);
+  C.ModelConfig.NumThreads := Config.ModelConfig.NumThreads;
+  C.ModelConfig.Provider := PAnsiChar(Config.ModelConfig.Provider);
+  C.ModelConfig.Debug := Ord(Config.ModelConfig.Debug);
+  C.ModelConfig.ModelType := PAnsiChar(Config.ModelConfig.ModelType);
+  C.ModelConfig.ModelingUnit := PAnsiChar(Config.ModelConfig.ModelingUnit);
+  C.ModelConfig.BpeVocab := PAnsiChar(Config.ModelConfig.BpeVocab);
+
+  C.DecodingMethod := PAnsiChar(Config.DecodingMethod);
+  C.MaxActivePaths := Config.MaxActivePaths;
+  C.EnableEndpoint := Ord(Config.EnableEndpoint);
+  C.Rule1MinTrailingSilence := Config.Rule1MinTrailingSilence;
+  C.Rule2MinTrailingSilence := Config.Rule2MinTrailingSilence;
+  C.Rule3MinUtteranceLength := Config.Rule3MinUtteranceLength;
+  C.HotwordsFile := PAnsiChar(Config.HotwordsFile);
+  C.HotwordsScore := Config.HotwordsScore;
+  C.CtcFstDecoderConfig.Graph := PAnsiChar(Config.CtcFstDecoderConfig.Graph);
+  C.CtcFstDecoderConfig.MaxActive := Config.CtcFstDecoderConfig.MaxActive;
+  C.RuleFsts := PAnsiChar(Config.RuleFsts);
+  C.RuleFars := PAnsiChar(Config.RuleFars);
+  C.BlankPenalty := Config.BlankPenalty;
+
+  Self.Handle := SherpaOnnxCreateOnlineRecognizer(@C);
+end;
+
+destructor TSherpaOnnxOnlineRecognizer.Destroy;
+begin
+  SherpaOnnxDestroyOnlineRecognizer(Self.Handle);
+  Self.Handle := nil;
+end;
+
+function TSherpaOnnxOnlineRecognizer.CreateStream: TSherpaOnnxOnlineStream;
+var
+  Stream: Pointer;
+begin
+  Stream := SherpaOnnxCreateOnlineStream(Self.Handle);
+  Result := TSherpaOnnxOnlineStream.Create(Stream);
+end;
+
+function TSherpaOnnxOnlineRecognizer.CreateStream(Hotwords: AnsiString): TSherpaOnnxOnlineStream;
+var
+  Stream: Pointer;
+begin
+  Stream := SherpaOnnxCreateOnlineStreamWithHotwords(Self.Handle, PAnsiChar(Hotwords));
+  Result := TSherpaOnnxOnlineStream.Create(Stream);
+end;
+
+function TSherpaOnnxOnlineRecognizer.IsReady(Stream: TSherpaOnnxOnlineStream): Boolean;
+begin
+  Result := SherpaOnnxIsOnlineStreamReady(Self.Handle, Stream.Handle) = 1;
+end;
+
+procedure TSherpaOnnxOnlineRecognizer.Decode(Stream: TSherpaOnnxOnlineStream);
+begin
+  SherpaOnnxDecodeOnlineStream(Self.Handle, Stream.Handle);
+end;
+
+procedure TSherpaOnnxOnlineRecognizer.Reset(Stream: TSherpaOnnxOnlineStream);
+begin
+  SherpaOnnxOnlineStreamReset(Self.Handle, Stream.Handle);
+end;
+
+function TSherpaOnnxOnlineRecognizer.IsEndpoint(Stream: TSherpaOnnxOnlineStream): Boolean;
+begin
+  Result := SherpaOnnxOnlineStreamIsEndpoint(Self.Handle, Stream.Handle) = 1;
+end;
+
+function TSherpaOnnxOnlineRecognizer.GetResult(Stream: TSherpaOnnxOnlineStream): TSherpaOnnxOnlineRecognizerResult;
+var
+  pJson: PAnsiChar;
+  JsonData: TJSONData;
+  JsonObject : TJSONObject;
+  JsonEnum: TJSONEnum;
+  I: Integer;
+begin
+  pJson := SherpaOnnxGetOnlineStreamResultAsJson(Self.Handle, Stream.Handle);
+
+  {
+   - https://www.freepascal.org/daily/doc/fcl/fpjson/getjson.html
+   - https://www.freepascal.org/daily/doc/fcl/fpjson/tjsondata.html
+   - https://www.freepascal.org/daily/doc/fcl/fpjson/tjsonobject.html
+   - https://www.freepascal.org/daily/doc/fcl/fpjson/tjsonenum.html
+  }
+
+  JsonData := GetJSON(AnsiString(pJson), False);
+
+  JsonObject := JsonData as TJSONObject;
+
+  Result.Text := JsonObject.Strings['text'];
+
+  SetLength(Result.Tokens, JsonObject.Arrays['tokens'].Count);
+
+  I := 0;
+  for JsonEnum in JsonObject.Arrays['tokens'] do
+  begin
+    Result.Tokens[I] := JsonEnum.Value.AsString;
+    Inc(I);
+  end;
+
+  SetLength(Result.Timestamps, JsonObject.Arrays['timestamps'].Count);
+  I := 0;
+  for JsonEnum in JsonObject.Arrays['timestamps'] do
+  begin
+    Result.Timestamps[I] := JsonEnum.Value.AsFloat;
+    Inc(I);
+  end;
+
+  SherpaOnnxDestroyOnlineStreamResultJson(pJson);
+end;
+
+
+constructor TSherpaOnnxOnlineStream.Create(P: Pointer);
+begin
+  Self.Handle := P;
+end;
+
+destructor TSherpaOnnxOnlineStream.Destroy;
+begin
+  SherpaOnnxDestroyOnlineStream(Self.Handle);
+  Self.Handle := nil;
+end;
+
+procedure TSherpaOnnxOnlineStream.AcceptWaveform(Samples: array of Single; SampleRate: Integer);
+begin
+  SherpaOnnxOnlineStreamAcceptWaveform(Self.Handle, SampleRate,
+    pcfloat(Samples), Length(Samples));
+end;
+
+procedure TSherpaOnnxOnlineStream.InputFinished;
+begin
+  SherpaOnnxOnlineStreamInputFinished(Self.Handle);
+end;
+
 end.