merge load and chain

Author: mthrok

torchaudio/csrc/sox_io.cpp

@@ -1,6 +1,7 @@
 #include <sox.h>
 #include <torchaudio/csrc/sox_io.h>
 #include <torchaudio/csrc/sox_utils.h>
+#include <torchaudio/csrc/sox_effects.h>
 
 using namespace torch::indexing;
 using namespace torchaudio::sox_utils;
@@ -60,64 +61,19 @@ c10::intrusive_ptr<TensorSignal> load_audio_file(
         "Invalid argument: num_frames must be -1 or greater than 0.");
   }
 
-  SoxFormat sf(sox_open_read(
-      path.c_str(),
-      /*signal=*/nullptr,
-      /*encoding=*/nullptr,
-      /*filetype=*/nullptr));
-
-  validate_input_file(sf);
-
-  const int64_t num_channels = sf->signal.channels;
-  const int64_t num_total_samples = sf->signal.length;
-  const int64_t sample_start = sf->signal.channels * frame_offset;
-
-  if (sox_seek(sf, sample_start, 0) == SOX_EOF) {
-    throw std::runtime_error("Error reading audio file: offset past EOF.");
+  std::vector<std::vector<std::string>> effects;
+  if (num_frames != -1) {
+    std::ostringstream offset, frames;
+    offset << frame_offset << "s";
+    frames << "+" << num_frames << "s";
+    effects.emplace_back(std::vector<std::string>{"trim", offset.str(), frames.str()});
+  } else if (frame_offset != 0) {
+    std::ostringstream offset;
+    offset << frame_offset << "s";
+    effects.emplace_back(std::vector<std::string>{"trim", offset.str()});
   }
 
-  const int64_t sample_end = [&]() {
-    if (num_frames == -1)
-      return num_total_samples;
-    const int64_t sample_end_ = num_channels * num_frames + sample_start;
-    if (num_total_samples < sample_end_) {
-      // For lossy encoding, it is difficult to predict exact size of buffer for
-      // reading the number of samples required.
-      // So we allocate buffer size of given `num_frames` and ask sox to read as
-      // much as possible. For lossless format, sox reads exact number of
-      // samples, but for lossy encoding, sox can end up reading less. (i.e.
-      // mp3) For the consistent behavior specification between lossy/lossless
-      // format, we allow users to provide `num_frames` value that exceeds #of
-      // available samples, and we adjust it here.
-      return num_total_samples;
-    }
-    return sample_end_;
-  }();
-
-  const int64_t max_samples = sample_end - sample_start;
-
-  // Read samples into buffer
-  std::vector<sox_sample_t> buffer;
-  buffer.reserve(max_samples);
-  const int64_t num_samples = sox_read(sf, buffer.data(), max_samples);
-  if (num_samples == 0) {
-    throw std::runtime_error(
-        "Error reading audio file: empty file or read operation failed.");
-  }
-  // NOTE: num_samples may be smaller than max_samples if the input
-  // format is compressed (i.e. mp3).
-
-  // Convert to Tensor
-  auto tensor = convert_to_tensor(
-      buffer.data(),
-      num_samples,
-      num_channels,
-      get_dtype(sf->encoding.encoding, sf->signal.precision),
-      normalize,
-      channels_first);
-
-  return c10::make_intrusive<TensorSignal>(
-      tensor, static_cast<int64_t>(sf->signal.rate), channels_first);
+  return torchaudio::sox_effects::apply_effects_file(path, effects, normalize, channels_first);
 }
 
 void save_audio_file(