Support writing generated audio samples to wave files (#363)

@@ -93,6 +93,7 @@ list(APPEND sources
   offline-tts-vits-model-config.cc
   offline-tts-vits-model.cc
   offline-tts.cc
+  wave-writer.cc
 )
 
 if(SHERPA_ONNX_ENABLE_CHECK)

@@ -53,7 +53,7 @@ static std::unordered_map<std::string, int32_t> ReadTokens(
       exit(-1);
     }
 #endif
-    token2id.insert({sym, id});
+    token2id.insert({std::move(sym), id});
   }
 
   return token2id;
@@ -78,6 +78,7 @@ static std::vector<int32_t> ConvertTokensToIds(
 Lexicon::Lexicon(const std::string &lexicon, const std::string &tokens,
                  const std::string &punctuations) {
   token2id_ = ReadTokens(tokens);
+  blank_ = token2id_.at(" ");
   std::ifstream is(lexicon);
 
   std::string word;
@@ -149,6 +150,11 @@ std::vector<int64_t> Lexicon::ConvertTextToTokenIds(
     ans.insert(ans.end(), prefix.begin(), prefix.end());
     ans.insert(ans.end(), token_ids.begin(), token_ids.end());
     ans.insert(ans.end(), suffix.rbegin(), suffix.rend());
+    ans.push_back(blank_);
+  }
+
+  if (!ans.empty()) {
+    ans.resize(ans.size() - 1);
   }
 
   return ans;

@@ -24,6 +24,7 @@ class Lexicon {
   std::unordered_map<std::string, std::vector<int32_t>> word2ids_;
   std::unordered_set<std::string> punctuations_;
   std::unordered_map<std::string, int32_t> token2id_;
+  int32_t blank_;  // ID for the blank token
 };
 
 }  // namespace sherpa_onnx

@@ -6,6 +6,7 @@
 
 #include "sherpa-onnx/csrc/offline-tts.h"
 #include "sherpa-onnx/csrc/parse-options.h"
+#include "sherpa-onnx/csrc/wave-writer.h"
 
 int main(int32_t argc, char *argv[]) {
   const char *kUsageMessage = R"usage(
@@ -15,13 +16,34 @@ Offline text-to-speech with sherpa-onnx
  --vits-model /path/to/model.onnx \
  --vits-lexicon /path/to/lexicon.txt \
  --vits-tokens /path/to/tokens.txt
+ --output-filename ./generated.wav \
  'some text within single quotes'
 
-It will generate a file test.wav.
+It will generate a file ./generated.wav as specified by --output-filename.
+
+You can download a test model from
+https://huggingface.co/csukuangfj/vits-ljs
+
+For instance, you can use:
+wget https://huggingface.co/csukuangfj/vits-ljs/resolve/main/vits-ljs.onnx
+wget https://huggingface.co/csukuangfj/vits-ljs/resolve/main/lexicon.txt
+wget https://huggingface.co/csukuangfj/vits-ljs/resolve/main/tokens.txt
+
+./bin/sherpa-onnx-offline-tts \
+  --vits-model=./vits-ljs.onnx \
+  --vits-lexicon=./lexicon.txt \
+  --vits-tokens=./tokens.txt \
+  --output-filename=./generated.wav \
+  'liliana, the most beautiful and lovely assistant of our team!'
 )usage";
 
   sherpa_onnx::ParseOptions po(kUsageMessage);
+  std::string output_filename = "./generated.wav";
+  po.Register("output-filename", &output_filename,
+              "Path to save the generated audio");
+
   sherpa_onnx::OfflineTtsConfig config;
+
   config.Register(&po);
   po.Read(argc, argv);
 
@@ -47,11 +69,15 @@ It will generate a file test.wav.
   sherpa_onnx::OfflineTts tts(config);
   auto audio = tts.Generate(po.GetArg(1));
 
-  std::ofstream os("t.pcm", std::ios::binary);
-  os.write(reinterpret_cast<const char *>(audio.samples.data()),
-           sizeof(float) * audio.samples.size());
+  bool ok = sherpa_onnx::WriteWave(output_filename, audio.sample_rate,
+                                   audio.samples.data(), audio.samples.size());
+  if (!ok) {
+    fprintf(stderr, "Failed to write wave to %s\n", output_filename.c_str());
+    exit(EXIT_FAILURE);
+  }
 
-  // sox -t raw -r 22050 -b 32 -e floating-point -c 1 ./t.pcm ./t.wav
+  fprintf(stderr, "The text is: %s\n", po.GetArg(1).c_str());
+  fprintf(stderr, "Saved to %s successfully!\n", output_filename.c_str());
 
   return 0;
 }

+// sherpa-onnx/csrc/wave-writer.cc
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#include "sherpa-onnx/csrc/wave-writer.h"
+
+#include <fstream>
+#include <string>
+#include <vector>
+
+#include "sherpa-onnx/csrc/macros.h"
+
+namespace sherpa_onnx {
+namespace {
+
+// see http://soundfile.sapp.org/doc/WaveFormat/
+//
+// Note: We assume little endian here
+// TODO(fangjun): Support big endian
+struct WaveHeader {
+  int32_t chunk_id;
+  int32_t chunk_size;
+  int32_t format;
+  int32_t subchunk1_id;
+  int32_t subchunk1_size;
+  int16_t audio_format;
+  int16_t num_channels;
+  int32_t sample_rate;
+  int32_t byte_rate;
+  int16_t block_align;
+  int16_t bits_per_sample;
+  int32_t subchunk2_id;    // a tag of this chunk
+  int32_t subchunk2_size;  // size of subchunk2
+};
+
+}  // namespace
+
+bool WriteWave(const std::string &filename, int32_t sampling_rate,
+               const float *samples, int32_t n) {
+  WaveHeader header;
+  header.chunk_id = 0x46464952;      // FFIR
+  header.format = 0x45564157;        // EVAW
+  header.subchunk1_id = 0x20746d66;  // "fmt "
+  header.subchunk1_size = 16;        // 16 for PCM
+  header.audio_format = 1;           // PCM =1
+
+  int32_t num_channels = 1;
+  int32_t bits_per_sample = 16;  // int16_t
+  header.num_channels = num_channels;
+  header.sample_rate = sampling_rate;
+  header.byte_rate = sampling_rate * num_channels * bits_per_sample / 8;
+  header.block_align = num_channels * bits_per_sample / 8;
+  header.bits_per_sample = bits_per_sample;
+  header.subchunk2_id = 0x61746164;  // atad
+  header.subchunk2_size = n * num_channels * bits_per_sample / 8;
+
+  header.chunk_size = 36 + header.subchunk2_size;
+
+  std::vector<int16_t> samples_int16(n);
+  for (int32_t i = 0; i != n; ++i) {
+    samples_int16[i] = samples[i] * 32676;
+  }
+
+  std::ofstream os(filename, std::ios::binary);
+  if (!os) {
+    SHERPA_ONNX_LOGE("Failed to create %s", filename.c_str());
+    return false;
+  }
+
+  os.write(reinterpret_cast<const char *>(&header), sizeof(header));
+  os.write(reinterpret_cast<const char *>(samples_int16.data()),
+           samples_int16.size() * sizeof(int16_t));
+
+  if (!os) {
+    SHERPA_ONNX_LOGE("Write %s failed", filename.c_str());
+    return false;
+  }
+
+  return true;
+}
+
+}  // namespace sherpa_onnx

+// sherpa-onnx/csrc/wave-writer.h
+//
+// Copyright (c)  2023  Xiaomi Corporation
+
+#ifndef SHERPA_ONNX_CSRC_WAVE_WRITER_H_
+#define SHERPA_ONNX_CSRC_WAVE_WRITER_H_
+
+#include <cstdint>
+#include <string>
+
+namespace sherpa_onnx {
+
+// Write a single channel wave file.
+// Note that the input samples are in the range [-1, 1]. It will be multiplied
+// by 32767 and saved in int16_t format in the wave file.
+//
+// @param filename Path to save the samples.
+// @param sampling_rate Sample rate of the samples.
+// @param samples Pointer to the samples
+// @param n Number of samples
+// @return Return true if the write succeeds; return false otherwise.
+bool WriteWave(const std::string &filename, int32_t sampling_rate,
+               const float *samples, int32_t n);
+
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_WAVE_WRITER_H_