Add bits_per_sample to info (#1177)

test/torchaudio_unittest/soundfile_backend/common.py

@@ -26,7 +26,7 @@ def skipIfFormatNotSupported(fmt):
         import soundfile
 
         fmts = soundfile.available_formats()
-        return skipIf(fmt not in fmts, f'"{fmt}" is not supported by sondfile')
+        return skipIf(fmt not in fmts, f'"{fmt}" is not supported by soundfile')
     return skipIf(True, '"soundfile" not available.')
 
 

test/torchaudio_unittest/soundfile_backend/info_test.py

+from unittest.mock import patch
+import warnings
+
 import torch
 from torchaudio.backend import _soundfile_backend as soundfile_backend
 from torchaudio._internal import module_utils as _mod_utils
@@ -18,10 +21,11 @@ if _mod_utils.is_module_available("soundfile"):
 @skipIfNoModule("soundfile")
 class TestInfo(TempDirMixin, PytorchTestCase):
     @parameterize(
-        ["float32", "int32", "int16", "uint8"], [8000, 16000], [1, 2],
+        [("float32", 32), ("int32", 32), ("int16", 16), ("uint8", 8)], [8000, 16000], [1, 2],
     )
-    def test_wav(self, dtype, sample_rate, num_channels):
+    def test_wav(self, dtype_and_bit_depth, sample_rate, num_channels):
         """`soundfile_backend.info` can check wav file correctly"""
+        dtype, bits_per_sample = dtype_and_bit_depth
         duration = 1
         path = self.get_temp_path("data.wav")
         data = get_wav_data(
@@ -32,12 +36,14 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == bits_per_sample
 
     @parameterize(
-        ["float32", "int32", "int16", "uint8"], [8000, 16000], [4, 8, 16, 32],
+        [("float32", 32), ("int32", 32), ("int16", 16), ("uint8", 8)], [8000, 16000], [1, 2],
     )
-    def test_wav_multiple_channels(self, dtype, sample_rate, num_channels):
+    def test_wav_multiple_channels(self, dtype_and_bit_depth, sample_rate, num_channels):
         """`soundfile_backend.info` can check wav file with channels more than 2 correctly"""
+        dtype, bits_per_sample = dtype_and_bit_depth
         duration = 1
         path = self.get_temp_path("data.wav")
         data = get_wav_data(
@@ -48,6 +54,7 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == bits_per_sample
 
     @parameterize([8000, 16000], [1, 2])
     @skipIfFormatNotSupported("FLAC")
@@ -63,6 +70,7 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == num_frames
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 16
 
     @parameterize([8000, 16000], [1, 2])
     @skipIfFormatNotSupported("OGG")
@@ -78,18 +86,42 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 0
 
-    @parameterize([8000, 16000], [1, 2])
+    @parameterize([8000, 16000], [1, 2], [('PCM_24', 24), ('PCM_32', 32)])
     @skipIfFormatNotSupported("NIST")
-    def test_sphere(self, sample_rate, num_channels):
+    def test_sphere(self, sample_rate, num_channels, subtype_and_bit_depth):
         """`soundfile_backend.info` can check sph file correctly"""
         duration = 1
         num_frames = sample_rate * duration
         data = torch.randn(num_frames, num_channels).numpy()
         path = self.get_temp_path("data.nist")
-        soundfile.write(path, data, sample_rate)
+        subtype, bits_per_sample = subtype_and_bit_depth
+        soundfile.write(path, data, sample_rate, subtype=subtype)
 
         info = soundfile_backend.info(path)
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == bits_per_sample
+
+    def test_unknown_subtype_warning(self):
+        """soundfile_backend.info issues a warning when the subtype is unknown
+
+        This will happen if a new subtype is supported in SoundFile: the _SUBTYPE_TO_BITS_PER_SAMPLE
+        dict should be updated.
+        """
+        def _mock_info_func(_):
+            class MockSoundFileInfo:
+                samplerate = 8000
+                frames = 356
+                channels = 2
+                subtype = 'UNSEEN_SUBTYPE'
+            return MockSoundFileInfo()
+
+        with patch("soundfile.info", _mock_info_func):
+            with warnings.catch_warnings(record=True) as w:
+                info = soundfile_backend.info("foo")
+                assert len(w) == 1
+                assert "UNSEEN_SUBTYPE subtype is unknown to TorchAudio" in str(w[-1].message)
+                assert info.bits_per_sample == 0

test/torchaudio_unittest/sox_io_backend/info_test.py

@@ -36,6 +36,7 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == sox_utils.get_bit_depth(dtype)
 
     @parameterized.expand(list(itertools.product(
         ['float32', 'int32', 'int16', 'uint8'],
@@ -52,6 +53,7 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == sox_utils.get_bit_depth(dtype)
 
     @parameterized.expand(list(itertools.product(
         [8000, 16000],
@@ -71,6 +73,7 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         # mp3 does not preserve the number of samples
         # assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 0  # bit_per_sample is irrelevant for compressed formats
 
     @parameterized.expand(list(itertools.product(
         [8000, 16000],
@@ -89,6 +92,7 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 24  # FLAC standard
 
     @parameterized.expand(list(itertools.product(
         [8000, 16000],
@@ -107,20 +111,23 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 0  # bit_per_sample is irrelevant for compressed formats
 
     @parameterized.expand(list(itertools.product(
         [8000, 16000],
         [1, 2],
+        [16, 32],
     )), name_func=name_func)
-    def test_sphere(self, sample_rate, num_channels):
+    def test_sphere(self, sample_rate, num_channels, bits_per_sample):
         """`sox_io_backend.info` can check sph file correctly"""
         duration = 1
         path = self.get_temp_path('data.sph')
-        sox_utils.gen_audio_file(path, sample_rate, num_channels, duration=duration)
+        sox_utils.gen_audio_file(path, sample_rate, num_channels, duration=duration, bit_depth=bits_per_sample)
         info = sox_io_backend.info(path)
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == bits_per_sample
 
     @parameterized.expand(list(itertools.product(
         ['float32', 'int32', 'int16', 'uint8'],
@@ -131,13 +138,15 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         """`sox_io_backend.info` can check amb file correctly"""
         duration = 1
         path = self.get_temp_path('data.amb')
+        bits_per_sample = sox_utils.get_bit_depth(dtype)
         sox_utils.gen_audio_file(
             path, sample_rate, num_channels,
-            bit_depth=sox_utils.get_bit_depth(dtype), duration=duration)
+            bit_depth=bits_per_sample, duration=duration)
         info = sox_io_backend.info(path)
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == bits_per_sample
 
     def test_amr_nb(self):
         """`sox_io_backend.info` can check amr-nb file correctly"""
@@ -146,11 +155,13 @@ class TestInfo(TempDirMixin, PytorchTestCase):
         sample_rate = 8000
         path = self.get_temp_path('data.amr-nb')
         sox_utils.gen_audio_file(
-            path, sample_rate=sample_rate, num_channels=num_channels, bit_depth=16, duration=duration)
+            path, sample_rate=sample_rate, num_channels=num_channels, bit_depth=16,
+            duration=duration)
         info = sox_io_backend.info(path)
         assert info.sample_rate == sample_rate
         assert info.num_frames == sample_rate * duration
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 0
 
 
 @skipIfNoExtension
@@ -167,6 +178,7 @@ class TestInfoOpus(PytorchTestCase):
         assert info.sample_rate == 48000
         assert info.num_frames == 32768
         assert info.num_channels == num_channels
+        assert info.bits_per_sample == 0  # bit_per_sample is irrelevant for compressed formats
 
 
 @skipIfNoExtension
@@ -184,3 +196,4 @@ class TestLoadWithoutExtension(PytorchTestCase):
         path = get_asset_path("mp3_without_ext")
         sinfo = sox_io_backend.info(path, format="mp3")
         assert sinfo.sample_rate == 16000
+        assert sinfo.bits_per_sample == 0  # bit_per_sample is irrelevant for compressed formats

torchaudio/backend/_soundfile_backend.py

@@ -11,6 +11,45 @@ if _mod_utils.is_module_available("soundfile"):
     import soundfile
 
 
+# Mapping from soundfile subtype to number of bits per sample.
+# This is mostly heuristical and the value is set to 0 when it is irrelevant
+# (lossy formats) or when it can't be inferred.
+# For ADPCM (and G72X) subtypes, it's hard to infer the bit depth because it's not part of the standard:
+# According to https://en.wikipedia.org/wiki/Adaptive_differential_pulse-code_modulation#In_telephony,
+# the default seems to be 8 bits but it can be compressed further to 4 bits.
+# The dict is inspired from
+# https://github.com/bastibe/python-soundfile/blob/744efb4b01abc72498a96b09115b42a4cabd85e4/soundfile.py#L66-L94
+_SUBTYPE_TO_BITS_PER_SAMPLE = {
+    'PCM_S8': 8,  # Signed 8 bit data
+    'PCM_16': 16,  # Signed 16 bit data
+    'PCM_24': 24,  # Signed 24 bit data
+    'PCM_32': 32,  # Signed 32 bit data
+    'PCM_U8': 8,  # Unsigned 8 bit data (WAV and RAW only)
+    'FLOAT': 32,  # 32 bit float data
+    'DOUBLE': 64,  # 64 bit float data
+    'ULAW': 8,  # U-Law encoded. See https://en.wikipedia.org/wiki/G.711#Types
+    'ALAW': 8,  # A-Law encoded. See https://en.wikipedia.org/wiki/G.711#Types
+    'IMA_ADPCM': 0,  # IMA ADPCM.
+    'MS_ADPCM': 0,  # Microsoft ADPCM.
+    'GSM610': 0,  # GSM 6.10 encoding. (Wikipedia says 1.625 bit depth?? https://en.wikipedia.org/wiki/Full_Rate)
+    'VOX_ADPCM': 0,  # OKI / Dialogix ADPCM
+    'G721_32': 0,  # 32kbs G721 ADPCM encoding.
+    'G723_24': 0,  # 24kbs G723 ADPCM encoding.
+    'G723_40': 0,  # 40kbs G723 ADPCM encoding.
+    'DWVW_12': 12,  # 12 bit Delta Width Variable Word encoding.
+    'DWVW_16': 16,  # 16 bit Delta Width Variable Word encoding.
+    'DWVW_24': 24,  # 24 bit Delta Width Variable Word encoding.
+    'DWVW_N': 0,  # N bit Delta Width Variable Word encoding.
+    'DPCM_8': 8,  # 8 bit differential PCM (XI only)
+    'DPCM_16': 16,  # 16 bit differential PCM (XI only)
+    'VORBIS': 0,  # Xiph Vorbis encoding. (lossy)
+    'ALAC_16': 16,  # Apple Lossless Audio Codec (16 bit).
+    'ALAC_20': 20,  # Apple Lossless Audio Codec (20 bit).
+    'ALAC_24': 24,  # Apple Lossless Audio Codec (24 bit).
+    'ALAC_32': 32,  # Apple Lossless Audio Codec (32 bit).
+}
+
+
 @_mod_utils.requires_module("soundfile")
 def info(filepath: str, format: Optional[str] = None) -> AudioMetaData:
     """Get signal information of an audio file.
@@ -27,7 +66,15 @@ def info(filepath: str, format: Optional[str] = None) -> AudioMetaData:
         AudioMetaData: meta data of the given audio.
     """
     sinfo = soundfile.info(filepath)
-    return AudioMetaData(sinfo.samplerate, sinfo.frames, sinfo.channels)
+    if sinfo.subtype not in _SUBTYPE_TO_BITS_PER_SAMPLE:
+        warnings.warn(
+            f"The {sinfo.subtype} subtype is unknown to TorchAudio. As a result, the bits_per_sample "
+            "attribute will be set to 0. If you are seeing this warning, please "
+            "report by opening an issue on github (after checking for existing/closed ones). "
+            "You may otherwise ignore this warning."
+        )
+    bits_per_sample = _SUBTYPE_TO_BITS_PER_SAMPLE.get(sinfo.subtype, 0)
+    return AudioMetaData(sinfo.samplerate, sinfo.frames, sinfo.channels, bits_per_sample=bits_per_sample)
 
 
 _SUBTYPE2DTYPE = {

torchaudio/backend/common.py

@@ -12,11 +12,14 @@ class AudioMetaData:
     :ivar int sample_rate: Sample rate
     :ivar int num_frames: The number of frames
     :ivar int num_channels: The number of channels
+    :ivar int bits_per_sample: The number of bits per sample. This is 0 for lossy formats,
+        or when it cannot be accurately inferred.
     """
-    def __init__(self, sample_rate: int, num_frames: int, num_channels: int):
+    def __init__(self, sample_rate: int, num_frames: int, num_channels: int, bits_per_sample: int):
         self.sample_rate = sample_rate
         self.num_frames = num_frames
         self.num_channels = num_channels
+        self.bits_per_sample = bits_per_sample
 
 
 @_mod_utils.deprecated('Please migrate to `AudioMetaData`.', '0.9.0')

torchaudio/backend/sox_io_backend.py

@@ -32,7 +32,8 @@ def info(
     # Cast to str in case type is `pathlib.Path`
     filepath = str(filepath)
     sinfo = torch.ops.torchaudio.sox_io_get_info(filepath, format)
-    return AudioMetaData(sinfo.get_sample_rate(), sinfo.get_num_frames(), sinfo.get_num_channels())
+    return AudioMetaData(sinfo.get_sample_rate(), sinfo.get_num_frames(), sinfo.get_num_channels(),
+                         sinfo.get_bits_per_sample())
 
 
 @_mod_utils.requires_module('torchaudio._torchaudio')

torchaudio/csrc/sox/io.cpp

@@ -13,10 +13,12 @@ namespace sox_io {
 SignalInfo::SignalInfo(
     const int64_t sample_rate_,
     const int64_t num_channels_,
-    const int64_t num_frames_)
+    const int64_t num_frames_,
+    const int64_t bits_per_sample_)
     : sample_rate(sample_rate_),
       num_channels(num_channels_),
-      num_frames(num_frames_){};
+      num_frames(num_frames_),
+      bits_per_sample(bits_per_sample_){};
 
 int64_t SignalInfo::getSampleRate() const {
   return sample_rate;
@@ -30,6 +32,10 @@ int64_t SignalInfo::getNumFrames() const {
   return num_frames;
 }
 
+int64_t SignalInfo::getBitsPerSample() const {
+  return bits_per_sample;
+}
+
 c10::intrusive_ptr<SignalInfo> get_info(
     const std::string& path,
     c10::optional<std::string>& format) {
@@ -46,7 +52,8 @@ c10::intrusive_ptr<SignalInfo> get_info(
   return c10::make_intrusive<SignalInfo>(
       static_cast<int64_t>(sf->signal.rate),
       static_cast<int64_t>(sf->signal.channels),
-      static_cast<int64_t>(sf->signal.length / sf->signal.channels));
+      static_cast<int64_t>(sf->signal.length / sf->signal.channels),
+      static_cast<int64_t>(sf->encoding.bits_per_sample));
 }
 
 namespace {

torchaudio/csrc/sox/io.h

@@ -15,14 +15,17 @@ struct SignalInfo : torch::CustomClassHolder {
   int64_t sample_rate;
   int64_t num_channels;
   int64_t num_frames;
+  int64_t bits_per_sample;
 
   SignalInfo(
       const int64_t sample_rate_,
       const int64_t num_channels_,
-      const int64_t num_frames_);
+      const int64_t num_frames_,
+      const int64_t bits_per_sample_);
   int64_t getSampleRate() const;
   int64_t getNumChannels() const;
   int64_t getNumFrames() const;
+  int64_t getBitsPerSample() const;
 };
 
 c10::intrusive_ptr<SignalInfo> get_info(

torchaudio/csrc/sox/register.cpp

@@ -42,7 +42,8 @@ TORCH_LIBRARY_FRAGMENT(torchaudio, m) {
   m.class_<torchaudio::sox_io::SignalInfo>("SignalInfo")
       .def("get_sample_rate", &torchaudio::sox_io::SignalInfo::getSampleRate)
       .def("get_num_channels", &torchaudio::sox_io::SignalInfo::getNumChannels)
-      .def("get_num_frames", &torchaudio::sox_io::SignalInfo::getNumFrames);
+      .def("get_num_frames", &torchaudio::sox_io::SignalInfo::getNumFrames)
+      .def("get_bits_per_sample", &torchaudio::sox_io::SignalInfo::getBitsPerSample);
 
   m.def("torchaudio::sox_io_get_info", &torchaudio::sox_io::get_info);
   m.def(