Conform to sox library a bit better

torchaudio/torch_sox.cpp

@@ -9,6 +9,9 @@
 
 namespace torch { namespace audio {
 int read_audio_file(const std::string& file_name, at::Tensor output) {
+  if (sox_init() != SOX_SUCCESS) {
+    throw std::runtime_error("Error initializing sox library");
+  }
   sox_format_t* fd = sox_open_read(
       file_name.c_str(),
       /*signal=*/nullptr,
@@ -25,7 +28,7 @@ int read_audio_file(const std::string& file_name, at::Tensor output) {
     throw std::runtime_error("Error reading audio file: unknown length");
   }
 
-  std::vector<int32_t> buffer(buffer_length);
+  std::vector<sox_sample_t> buffer(buffer_length);
   const int64_t samples_read = sox_read(fd, buffer.data(), buffer_length);
   if (samples_read == 0) {
     throw std::runtime_error(
@@ -40,6 +43,8 @@ int read_audio_file(const std::string& file_name, at::Tensor output) {
     std::copy(buffer.begin(), buffer.begin() + samples_read, data);
   });
 
+  sox_quit();
+
   return sample_rate;
 }
 
@@ -48,12 +53,15 @@ void write_audio_file(
     at::Tensor tensor,
     const std::string& extension,
     int sample_rate) {
+  if (sox_init() != SOX_SUCCESS) {
+    throw std::runtime_error("Error initializing sox library");
+  }
+
   if (!tensor.is_contiguous()) {
     throw std::runtime_error(
         "Error writing audio file: input tensor must be contiguous");
   }
 
-  // Create sox objects and write into int32_t buffer.
   sox_signalinfo_t signal;
   signal.rate = sample_rate;
   signal.channels = tensor.size(1);
@@ -77,7 +85,7 @@ void write_audio_file(
         "Error writing audio file: could not open file for writing");
   }
 
-  std::vector<int32_t> buffer(tensor.numel());
+  std::vector<sox_sample_t> buffer(tensor.numel());
 
   AT_DISPATCH_ALL_TYPES(tensor.type(), "write_audio_buffer", [&] {
     auto* data = tensor.data<scalar_t>();
@@ -86,8 +94,9 @@ void write_audio_file(
 
   const auto samples_written = sox_write(fd, buffer.data(), buffer.size());
 
-  // Free buffer and sox structures.
+  // Free buffer and sox structures (before possibly throwing).
   sox_close(fd);
+  sox_quit();
 
   if (samples_written != buffer.size()) {
     throw std::runtime_error(