STT/native_client/client.cc

#include <stdlib.h>
#include <stdio.h>

#include <assert.h>
#include <errno.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <sstream>
#include <string>

#ifdef __APPLE__
#include <TargetConditionals.h>
#endif

#if defined(__ANDROID__) || defined(_MSC_VER) || TARGET_OS_IPHONE
#define NO_SOX
#endif

#if defined(_MSC_VER)
#define NO_DIR
#endif

#ifndef NO_SOX
#include <sox.h>
#endif

#ifndef NO_DIR
#include <dirent.h>
#include <unistd.h>
#endif // NO_DIR
#include <vector>

#include "coqui-stt.h"
#include "args.h"

typedef struct {
  const char* string;
  double cpu_time_overall;
} ds_result;

struct meta_word {
  std::string word;
  float start_time;
  float duration;
};

char*
CandidateTranscriptToString(const CandidateTranscript* transcript)
{
  std::string retval = "";
  for (int i = 0; i < transcript->num_tokens; i++) {
    const TokenMetadata& token = transcript->tokens[i];
    retval += token.text;
  }
  return strdup(retval.c_str());
}

std::vector<meta_word>
CandidateTranscriptToWords(const CandidateTranscript* transcript)
{
  std::vector<meta_word> word_list;

  std::string word = "";
  float word_start_time = 0;

  // Loop through each token
  for (int i = 0; i < transcript->num_tokens; i++) {
    const TokenMetadata& token = transcript->tokens[i];

    // Append token to word if it's not a space
    if (strcmp(token.text, u8" ") != 0) {
      // Log the start time of the new word
      if (word.length() == 0) {
        word_start_time = token.start_time;
      }
      word.append(token.text);
    }

    // Word boundary is either a space or the last token in the array
    if (strcmp(token.text, u8" ") == 0 || i == transcript->num_tokens-1) {
      float word_duration = token.start_time - word_start_time;

      if (word_duration < 0) {
        word_duration = 0;
      }

      meta_word w;
      w.word = word;
      w.start_time = word_start_time;
      w.duration = word_duration;

      word_list.push_back(w);

      // Reset
      word = "";
      word_start_time = 0;
    }
  }

  return word_list;
}

std::string
CandidateTranscriptToJSON(const CandidateTranscript *transcript)
{
  std::ostringstream out_string;

  std::vector<meta_word> words = CandidateTranscriptToWords(transcript);

  out_string << R"("metadata":{"confidence":)" << transcript->confidence << R"(},"words":[)";

  for (int i = 0; i < words.size(); i++) {
    meta_word w = words[i];
    out_string << R"({"word":")" << w.word << R"(","time":)" << w.start_time << R"(,"duration":)" << w.duration << "}";

    if (i < words.size() - 1) {
      out_string << ",";
    }
  }

  out_string << "]";

  return out_string.str();
}

char*
MetadataToJSON(Metadata* result)
{
  std::ostringstream out_string;
  out_string << "{\n";

  for (int j=0; j < result->num_transcripts; ++j) {
    const CandidateTranscript *transcript = &result->transcripts[j];

    if (j == 0) {
      out_string << CandidateTranscriptToJSON(transcript);

      if (result->num_transcripts > 1) {
        out_string << ",\n" << R"("alternatives")" << ":[\n";
      }
    } else {
      out_string << "{" << CandidateTranscriptToJSON(transcript) << "}";

      if (j < result->num_transcripts - 1) {
        out_string << ",\n";
      } else {
        out_string << "\n]";
      }
    }
  }

  out_string << "\n}\n";

  return strdup(out_string.str().c_str());
}

ds_result
LocalDsSTT(ModelState* aCtx, const short* aBuffer, size_t aBufferSize,
           bool extended_output, bool json_output)
{
  ds_result res = {0};

  clock_t ds_start_time = clock();

  // sphinx-doc: c_ref_inference_start
  if (extended_output) {
    Metadata *result = STT_SpeechToTextWithMetadata(aCtx, aBuffer, aBufferSize, 1);
    res.string = CandidateTranscriptToString(&result->transcripts[0]);
    STT_FreeMetadata(result);
  } else if (json_output) {
    Metadata *result = STT_SpeechToTextWithMetadata(aCtx, aBuffer, aBufferSize, json_candidate_transcripts);
    res.string = MetadataToJSON(result);
    STT_FreeMetadata(result);
  } else if (stream_size > 0) {
    StreamingState* ctx;
    int status = STT_CreateStream(aCtx, &ctx);
    if (status != STT_ERR_OK) {
      res.string = strdup("");
      return res;
    }
    size_t off = 0;
    const char *last = nullptr;
    const char *prev = nullptr;
    while (off < aBufferSize) {
      size_t cur = aBufferSize - off > stream_size ? stream_size : aBufferSize - off;
      STT_FeedAudioContent(ctx, aBuffer + off, cur);
      off += cur;
      prev = last;
      const char* partial = STT_IntermediateDecode(ctx);
      if (last == nullptr || strcmp(last, partial)) {
        printf("%s\n", partial);
        last = partial;
      } else {
        STT_FreeString((char *) partial);
      }
      if (prev != nullptr && prev != last) {
        STT_FreeString((char *) prev);
      }
    }
    if (last != nullptr) {
      STT_FreeString((char *) last);
    }
    res.string = STT_FinishStream(ctx);
  } else if (extended_stream_size > 0) {
    StreamingState* ctx;
    int status = STT_CreateStream(aCtx, &ctx);
    if (status != STT_ERR_OK) {
      res.string = strdup("");
      return res;
    }
    size_t off = 0;
    const char *last = nullptr;
    const char *prev = nullptr;
    while (off < aBufferSize) {
      size_t cur = aBufferSize - off > extended_stream_size ? extended_stream_size : aBufferSize - off;
      STT_FeedAudioContent(ctx, aBuffer + off, cur);
      off += cur;
      prev = last;
      const Metadata* result = STT_IntermediateDecodeWithMetadata(ctx, 1);
      const char* partial = CandidateTranscriptToString(&result->transcripts[0]);
      if (last == nullptr || strcmp(last, partial)) {
        printf("%s\n", partial);
       last = partial;
      } else {
        free((char *) partial);
      }
      if (prev != nullptr && prev != last) {
        free((char *) prev);
      }
      STT_FreeMetadata((Metadata *)result);
    }
    const Metadata* result = STT_FinishStreamWithMetadata(ctx, 1);
    res.string = CandidateTranscriptToString(&result->transcripts[0]);
    STT_FreeMetadata((Metadata *)result);
    free((char *) last);
  } else {
    res.string = STT_SpeechToText(aCtx, aBuffer, aBufferSize);
  }
  // sphinx-doc: c_ref_inference_stop

  clock_t ds_end_infer = clock();

  res.cpu_time_overall =
    ((double) (ds_end_infer - ds_start_time)) / CLOCKS_PER_SEC;

  return res;
}

typedef struct {
  char*  buffer;
  size_t buffer_size;
} ds_audio_buffer;

ds_audio_buffer
GetAudioBuffer(const char* path, int desired_sample_rate)
{
  ds_audio_buffer res = {0};

#ifndef NO_SOX
  sox_format_t* input = sox_open_read(path, NULL, NULL, NULL);
  assert(input);

  // Resample/reformat the audio so we can pass it through the MFCC functions
  sox_signalinfo_t target_signal = {
      static_cast<sox_rate_t>(desired_sample_rate), // Rate
      1, // Channels
      16, // Precision
      SOX_UNSPEC, // Length
      NULL // Effects headroom multiplier
  };

  sox_signalinfo_t interm_signal;

  sox_encodinginfo_t target_encoding = {
    SOX_ENCODING_SIGN2, // Sample format
    16, // Bits per sample
    0.0, // Compression factor
    sox_option_default, // Should bytes be reversed
    sox_option_default, // Should nibbles be reversed
    sox_option_default, // Should bits be reversed (pairs of bits?)
    sox_false // Reverse endianness
  };

#if TARGET_OS_OSX
  // It would be preferable to use sox_open_memstream_write here, but OS-X
  // doesn't support POSIX 2008, which it requires. See Issue #461.
  // Instead, we write to a temporary file.
  char* output_name = tmpnam(NULL);
  assert(output_name);
  sox_format_t* output = sox_open_write(output_name, &target_signal,
                                        &target_encoding, "raw", NULL, NULL);
#else
  sox_format_t* output = sox_open_memstream_write(&res.buffer,
                                                  &res.buffer_size,
                                                  &target_signal,
                                                  &target_encoding,
                                                  "raw", NULL);
#endif

  assert(output);

  if ((int)input->signal.rate < desired_sample_rate) {
    fprintf(stderr, "Warning: original sample rate (%d) is lower than %dkHz. "
                    "Up-sampling might produce erratic speech recognition.\n",
                    desired_sample_rate, (int)input->signal.rate);
  }

  // Setup the effects chain to decode/resample
  char* sox_args[10];
  sox_effects_chain_t* chain =
    sox_create_effects_chain(&input->encoding, &output->encoding);

  interm_signal = input->signal;

  sox_effect_t* e = sox_create_effect(sox_find_effect("input"));
  sox_args[0] = (char*)input;
  assert(sox_effect_options(e, 1, sox_args) == SOX_SUCCESS);
  assert(sox_add_effect(chain, e, &interm_signal, &input->signal) ==
         SOX_SUCCESS);
  free(e);

  e = sox_create_effect(sox_find_effect("rate"));
  assert(sox_effect_options(e, 0, NULL) == SOX_SUCCESS);
  assert(sox_add_effect(chain, e, &interm_signal, &output->signal) ==
         SOX_SUCCESS);
  free(e);

  e = sox_create_effect(sox_find_effect("channels"));
  assert(sox_effect_options(e, 0, NULL) == SOX_SUCCESS);
  assert(sox_add_effect(chain, e, &interm_signal, &output->signal) ==
         SOX_SUCCESS);
  free(e);

  e = sox_create_effect(sox_find_effect("output"));
  sox_args[0] = (char*)output;
  assert(sox_effect_options(e, 1, sox_args) == SOX_SUCCESS);
  assert(sox_add_effect(chain, e, &interm_signal, &output->signal) ==
         SOX_SUCCESS);
  free(e);

  // Finally run the effects chain
  sox_flow_effects(chain, NULL, NULL);
  sox_delete_effects_chain(chain);

  // Close sox handles
  sox_close(output);
  sox_close(input);
#endif // NO_SOX

#ifdef NO_SOX
  // FIXME: Hack and support only mono 16-bits PCM with standard SoX header
  FILE* wave = fopen(path, "r");

  size_t rv;

  unsigned short audio_format;
  fseek(wave, 20, SEEK_SET); rv = fread(&audio_format, 2, 1, wave);

  unsigned short num_channels;
  fseek(wave, 22, SEEK_SET); rv = fread(&num_channels, 2, 1, wave);

  unsigned int sample_rate;
  fseek(wave, 24, SEEK_SET); rv = fread(&sample_rate, 4, 1, wave);

  unsigned short bits_per_sample;
  fseek(wave, 34, SEEK_SET); rv = fread(&bits_per_sample, 2, 1, wave);

  assert(audio_format == 1); // 1 is PCM
  assert(num_channels == 1); // MONO
  assert(sample_rate == desired_sample_rate); // at desired sample rate
  assert(bits_per_sample == 16); // 16 bits per sample

  fprintf(stderr, "audio_format=%d\n", audio_format);
  fprintf(stderr, "num_channels=%d\n", num_channels);
  fprintf(stderr, "sample_rate=%d (desired=%d)\n", sample_rate, desired_sample_rate);
  fprintf(stderr, "bits_per_sample=%d\n", bits_per_sample);

  fseek(wave, 40, SEEK_SET); rv = fread(&res.buffer_size, 4, 1, wave);
  fprintf(stderr, "res.buffer_size=%ld\n", res.buffer_size);

  fseek(wave, 44, SEEK_SET);
  res.buffer = (char*)malloc(sizeof(char) * res.buffer_size);
  rv = fread(res.buffer, sizeof(char), res.buffer_size, wave);

  fclose(wave);
#endif // NO_SOX

#if TARGET_OS_OSX
  res.buffer_size = (size_t)(output->olength * 2);
  res.buffer = (char*)malloc(sizeof(char) * res.buffer_size);
  FILE* output_file = fopen(output_name, "rb");
  assert(fread(res.buffer, sizeof(char), res.buffer_size, output_file) == res.buffer_size);
  fclose(output_file);
  unlink(output_name);
#endif

  return res;
}

void
ProcessFile(ModelState* context, const char* path, bool show_times)
{
  ds_audio_buffer audio = GetAudioBuffer(path, STT_GetModelSampleRate(context));

  // Pass audio to STT
  // We take half of buffer_size because buffer is a char* while
  // LocalDsSTT() expected a short*
  ds_result result = LocalDsSTT(context,
                                (const short*)audio.buffer,
                                audio.buffer_size / 2,
                                extended_metadata,
                                json_output);
  free(audio.buffer);

  if (result.string) {
    printf("%s\n", result.string);
    STT_FreeString((char*)result.string);
  }

  if (show_times) {
    printf("cpu_time_overall=%.05f\n",
           result.cpu_time_overall);
  }
}

std::vector<std::string>
SplitStringOnDelim(std::string in_string, std::string delim)
{
  std::vector<std::string> out_vector;
  char * tmp_str = new char[in_string.size() + 1];
  std::copy(in_string.begin(), in_string.end(), tmp_str);
  tmp_str[in_string.size()] = '\0';
  const char* token = strtok(tmp_str, delim.c_str());
  while( token != NULL ) {
    out_vector.push_back(token);
    token = strtok(NULL, delim.c_str());
  }
  delete[] tmp_str;
  return out_vector;
}

int
main(int argc, char **argv)
{
  if (!ProcessArgs(argc, argv)) {
    return 1;
  }

  // Initialise STT
  ModelState* ctx;
  // sphinx-doc: c_ref_model_start
  int status = STT_CreateModel(model, &ctx);
  if (status != 0) {
    char* error = STT_ErrorCodeToErrorMessage(status);
    fprintf(stderr, "Could not create model: %s\n", error);
    free(error);
    return 1;
  }

  if (set_beamwidth) {
    status = STT_SetModelBeamWidth(ctx, beam_width);
    if (status != 0) {
      fprintf(stderr, "Could not set model beam width.\n");
      return 1;
    }
  }

  if (scorer) {
    status = STT_EnableExternalScorer(ctx, scorer);
    if (status != 0) {
      fprintf(stderr, "Could not enable external scorer.\n");
      return 1;
    }
    if (set_alphabeta) {
      status = STT_SetScorerAlphaBeta(ctx, lm_alpha, lm_beta);
      if (status != 0) {
        fprintf(stderr, "Error setting scorer alpha and beta.\n");
        return 1;
      }
    }
  }
  // sphinx-doc: c_ref_model_stop

  if (hot_words) {
    std::vector<std::string> hot_words_ = SplitStringOnDelim(hot_words, ",");
    for ( std::string hot_word_ : hot_words_ ) {
      std::vector<std::string> pair_ = SplitStringOnDelim(hot_word_, ":");
      const char* word = (pair_[0]).c_str();
      // the strtof function will return 0 in case of non numeric characters
      // so, check the boost string before we turn it into a float
      bool boost_is_valid = (pair_[1].find_first_not_of("-.0123456789") == std::string::npos);
      float boost = strtof((pair_[1]).c_str(),0);
      status = STT_AddHotWord(ctx, word, boost);
      if (status != 0 || !boost_is_valid) {
        fprintf(stderr, "Could not enable hot-word.\n");
        return 1;
      }
    }
  }

#ifndef NO_SOX
  // Initialise SOX
  assert(sox_init() == SOX_SUCCESS);
#endif

  struct stat wav_info;
  if (0 != stat(audio, &wav_info)) {
    printf("Error on stat: %d\n", errno);
  }

  switch (wav_info.st_mode & S_IFMT) {
#ifndef _MSC_VER
    case S_IFLNK:
#endif
    case S_IFREG:
        ProcessFile(ctx, audio, show_times);
      break;

#ifndef NO_DIR
    case S_IFDIR:
        {
          printf("Running on directory %s\n", audio);
          DIR* wav_dir = opendir(audio);
          assert(wav_dir);

          struct dirent* entry;
          while ((entry = readdir(wav_dir)) != NULL) {
            std::string fname = std::string(entry->d_name);
            if (fname.find(".wav") == std::string::npos) {
              continue;
            }

            std::ostringstream fullpath;
            fullpath << audio << "/" << fname;
            std::string path = fullpath.str();
            printf("> %s\n", path.c_str());
            ProcessFile(ctx, path.c_str(), show_times);
          }
          closedir(wav_dir);
        }
      break;
#endif

    default:
        printf("Unexpected type for %s: %d\n", audio, (wav_info.st_mode & S_IFMT));
      break;
  }

#ifndef NO_SOX
  // Deinitialise and quit
  sox_quit();
#endif // NO_SOX

  STT_FreeModel(ctx);

  return 0;
}