Add Dart API for MatchaTTS models (#1687)

dart-api-examples/tts/run-matcha-en.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+
+set -ex
+
+dart pub get
+
+# please visit
+# https://k2-fsa.github.io/sherpa/onnx/tts/pretrained_models/matcha.html#matcha-icefall-en-us-ljspeech-american-english-1-female-speaker
+# matcha.html#matcha-icefall-en-us-ljspeech-american-english-1-female-speaker
+# to download more models
+if [ ! -f ./matcha-icefall-en_US-ljspeech/model-steps-3.onnx ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/tts-models/matcha-icefall-en_US-ljspeech.tar.bz2
+  tar xf matcha-icefall-en_US-ljspeech.tar.bz2
+  rm matcha-icefall-en_US-ljspeech.tar.bz2
+fi
+
+if [ ! -f ./hifigan_v2.onnx ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/vocoder-models/hifigan_v2.onnx
+fi
+
+dart run \
+  ./bin/matcha-en.dart \
+  --acoustic-model ./matcha-icefall-en_US-ljspeech/model-steps-3.onnx \
+  --vocoder ./hifigan_v2.onnx \
+  --tokens ./matcha-icefall-en_US-ljspeech/tokens.txt \
+  --data-dir ./matcha-icefall-en_US-ljspeech/espeak-ng-data \
+  --sid 0 \
+  --speed 1.0 \
+  --output-wav matcha-en-1.wav \
+  --text "Friends fell out often because life was changing so fast. The easiest thing in the world was to lose touch with someone." \
+
+ls -lh *.wav