Add metadata to source stream info

test/torchaudio_unittest/io/stream_reader_test.py

@@ -89,6 +89,12 @@ def test_src_info(self):
         s = StreamReader(self.get_src())
         assert s.num_src_streams == 6
 
+        metadata = {
+            'compatible_brands': 'isomiso2avc1mp41',
+            'encoder': 'Lavf58.76.100',
+            'major_brand': 'isom',
+            'minor_version': '512',
+        }
         expected = [
             StreamReaderSourceVideoStream(
                 media_type="video",
@@ -98,6 +104,7 @@ def test_src_info(self):
                 bit_rate=71925,
                 num_frames=325,
                 bits_per_sample=8,
+                metadata=metadata,
                 width=320,
                 height=180,
                 frame_rate=25.0,
@@ -110,6 +117,7 @@ def test_src_info(self):
                 bit_rate=72093,
                 num_frames=103,
                 bits_per_sample=0,
+                metadata=metadata,
                 sample_rate=8000.0,
                 num_channels=2,
             ),
@@ -121,6 +129,7 @@ def test_src_info(self):
                 bit_rate=None,
                 num_frames=None,
                 bits_per_sample=None,
+                metadata=metadata,
             ),
             StreamReaderSourceVideoStream(
                 media_type="video",
@@ -130,6 +139,7 @@ def test_src_info(self):
                 bit_rate=128783,
                 num_frames=390,
                 bits_per_sample=8,
+                metadata=metadata,
                 width=480,
                 height=270,
                 frame_rate=29.97002997002997,
@@ -142,6 +152,7 @@ def test_src_info(self):
                 bit_rate=128837,
                 num_frames=205,
                 bits_per_sample=0,
+                metadata=metadata,
                 sample_rate=16000.0,
                 num_channels=2,
             ),
@@ -153,11 +164,34 @@ def test_src_info(self):
                 bit_rate=None,
                 num_frames=None,
                 bits_per_sample=None,
+                metadata=metadata,
             ),
         ]
         output = [s.get_src_stream_info(i) for i in range(6)]
         assert expected == output
 
+    def test_id3tag(self):
+        s = StreamReader(self.get_src("steam-train-whistle-daniel_simon.mp3"))
+        output = s.get_src_stream_info(s.default_audio_stream)
+
+        expected = StreamReaderSourceAudioStream(
+            media_type="audio",
+            codec="mp3",
+            codec_long_name="MP3 (MPEG audio layer 3)",
+            format="fltp",
+            bit_rate=210571,
+            num_frames=0,
+            bits_per_sample=0,
+            metadata={
+                "title": "SoundBible.com Must Credit",
+                "artist": "SoundBible.com Must Credit",
+                "date": "2017",
+            },
+            sample_rate=44100.0,
+            num_channels=2,
+        )
+        assert output == expected
+
     def test_src_info_invalid_index(self):
         """`get_src_stream_info` does not segfault but raise an exception when input is invalid"""
         s = StreamReader(self.get_src())

torchaudio/csrc/ffmpeg/pybind/pybind.cpp

@@ -22,7 +22,7 @@ PYBIND11_MODULE(_torchaudio_ffmpeg, m) {
       .def(
           "find_best_video_stream",
           &StreamReaderFileObj::find_best_video_stream)
-      .def("get_src_stream_info", &StreamReaderFileObj::get_src_stream_info)
+      .def("get_src_stream_info", &StreamReaderFileObj::get_src_stream_info_pybind)
       .def("get_out_stream_info", &StreamReaderFileObj::get_out_stream_info)
       .def("seek", &StreamReaderFileObj::seek)
       .def("add_audio_stream", &StreamReaderFileObj::add_audio_stream)

torchaudio/csrc/ffmpeg/stream_reader.cpp

@@ -71,6 +71,17 @@ int64_t StreamReader::num_src_streams() const {
   return pFormatContext->nb_streams;
 }
 
+namespace {
+c10::Dict<std::string, std::string> parse_metadata(const AVDictionary * metadata) {
+  AVDictionaryEntry *tag = nullptr;
+  c10::Dict<std::string, std::string> ret;
+  while ((tag = av_dict_get(metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
+    ret.insert(std::string(tag->key), std::string(tag->value));
+  }
+  return ret;
+}
+} // namespace
+
 SrcStreamInfo StreamReader::get_src_stream_info(int i) const {
   validate_src_stream_index(i);
   AVStream* stream = pFormatContext->streams[i];
@@ -81,11 +92,13 @@ SrcStreamInfo StreamReader::get_src_stream_info(int i) const {
   ret.bit_rate = codecpar->bit_rate;
   ret.num_frames = stream->nb_frames;
   ret.bits_per_sample = codecpar->bits_per_raw_sample;
+  ret.metadata = parse_metadata(pFormatContext->metadata);
   const AVCodecDescriptor* desc = avcodec_descriptor_get(codecpar->codec_id);
   if (desc) {
     ret.codec_name = desc->name;
     ret.codec_long_name = desc->long_name;
   }
+
   switch (codecpar->codec_type) {
     case AVMEDIA_TYPE_AUDIO: {
       AVSampleFormat smp_fmt = static_cast<AVSampleFormat>(codecpar->format);

torchaudio/csrc/ffmpeg/stream_reader_wrapper.cpp

@@ -4,6 +4,16 @@ namespace torchaudio {
 namespace ffmpeg {
 namespace {
 
+// TODO:
+// merge the implementation with the one from stream_reader_binding.cpp
+std::map<std::string, std::string> convert_map(const c10::Dict<std::string, std::string>& src) {
+  std::map<std::string, std::string> ret;
+  for (const auto& it : src) {
+    ret.insert({it.key(), it.value()});
+  }
+  return ret;
+}
+
 SrcInfo convert(SrcStreamInfo ssi) {
   return SrcInfo(std::forward_as_tuple(
       av_get_media_type_string(ssi.media_type),
@@ -13,6 +23,24 @@ SrcInfo convert(SrcStreamInfo ssi) {
       ssi.bit_rate,
       ssi.num_frames,
       ssi.bits_per_sample,
+      ssi.metadata,
+      ssi.sample_rate,
+      ssi.num_channels,
+      ssi.width,
+      ssi.height,
+      ssi.frame_rate));
+}
+
+SrcInfoPyBind convert_pybind(SrcStreamInfo ssi) {
+  return SrcInfoPyBind(std::forward_as_tuple(
+      av_get_media_type_string(ssi.media_type),
+      ssi.codec_name,
+      ssi.codec_long_name,
+      ssi.fmt_name,
+      ssi.bit_rate,
+      ssi.num_frames,
+      ssi.bits_per_sample,
+      convert_map(ssi.metadata),
       ssi.sample_rate,
       ssi.num_channels,
       ssi.width,
@@ -33,6 +61,10 @@ SrcInfo StreamReaderBinding::get_src_stream_info(int64_t i) {
   return convert(StreamReader::get_src_stream_info(static_cast<int>(i)));
 }
 
+SrcInfoPyBind StreamReaderBinding::get_src_stream_info_pybind(int64_t i) {
+  return convert_pybind(StreamReader::get_src_stream_info(static_cast<int>(i)));
+}
+
 OutInfo StreamReaderBinding::get_out_stream_info(int64_t i) {
   return convert(StreamReader::get_out_stream_info(static_cast<int>(i)));
 }

torchaudio/csrc/ffmpeg/stream_reader_wrapper.h

@@ -5,6 +5,14 @@
 namespace torchaudio {
 namespace ffmpeg {
 
+// Because TorchScript requires c10::Dict type to pass dict,
+// while PyBind11 requires std::map type to pass dict,
+// we duplicate the return tuple.
+// Even though all the PyBind-based implementations are placed
+// in `pybind` directory, because std::map does not require pybind11
+// header, we define both of them here, for the sake of
+// better locality/maintainability.
+
 using SrcInfo = std::tuple<
     std::string, // media_type
     std::string, // codec name
@@ -13,6 +21,25 @@ using SrcInfo = std::tuple<
     int64_t, // bit_rate
     int64_t, // num_frames
     int64_t, // bits_per_sample
+    c10::Dict<std::string, std::string>, // metadata
+    // Audio
+    double, // sample_rate
+    int64_t, // num_channels
+    // Video
+    int64_t, // width
+    int64_t, // height
+    double // frame_rate
+    >;
+
+using SrcInfoPyBind = std::tuple<
+    std::string, // media_type
+    std::string, // codec name
+    std::string, // codec long name
+    std::string, // format name
+    int64_t, // bit_rate
+    int64_t, // num_frames
+    int64_t, // bits_per_sample
+    std::map<std::string, std::string>, // metadata
     // Audio
     double, // sample_rate
     int64_t, // num_channels
@@ -33,6 +60,7 @@ struct StreamReaderBinding : public StreamReader,
                              public torch::CustomClassHolder {
   explicit StreamReaderBinding(AVFormatContextPtr&& p);
   SrcInfo get_src_stream_info(int64_t i);
+  SrcInfoPyBind get_src_stream_info_pybind(int64_t i);
   OutInfo get_out_stream_info(int64_t i);
 
   int64_t process_packet(

torchaudio/csrc/ffmpeg/typedefs.h

@@ -14,6 +14,7 @@ struct SrcStreamInfo {
   int64_t bit_rate = 0;
   int64_t num_frames = 0;
   int bits_per_sample = 0;
+  c10::Dict<std::string, std::string> metadata{};
   // Audio
   double sample_rate = 0;
   int num_channels = 0;

torchaudio/io/_compat.py

@@ -12,9 +12,9 @@ def _info_audio(
     i = s.find_best_audio_stream()
     sinfo = s.get_src_stream_info(i)
     return AudioMetaData(
-        int(sinfo[7]),
+        int(sinfo[8]),
         sinfo[5],
-        sinfo[8],
+        sinfo[9],
         sinfo[6],
         sinfo[1].upper(),
     )

torchaudio/io/_stream_reader.py

@@ -61,6 +61,9 @@ class StreamReaderSourceStream:
     """This is the number of valid bits in each output sample.
     For compressed format, it can be 0.
     """
+    metadata: Dict[str, str]
+    """Metadata attached to the source media.
+    Note that metadata is common across the source streams."""
 
 
 @dataclass
@@ -108,13 +111,14 @@ class StreamReaderSourceVideoStream(StreamReaderSourceStream):
 _BIT_RATE = 4
 _NUM_FRAMES = 5
 _BPS = 6
+_METADATA = 7
 # - AUDIO
-_SAMPLE_RATE = 7
-_NUM_CHANNELS = 8
+_SAMPLE_RATE = 8
+_NUM_CHANNELS = 9
 # - VIDEO
-_WIDTH = 9
-_HEIGHT = 10
-_FRAME_RATE = 11
+_WIDTH = 10
+_HEIGHT = 11
+_FRAME_RATE = 12
 
 
 def _parse_si(i):
@@ -125,6 +129,7 @@ def _parse_si(i):
     bit_rate = i[_BIT_RATE]
     num_frames = i[_NUM_FRAMES]
     bps = i[_BPS]
+    metadata = i[_METADATA]
     if media_type == "audio":
         return StreamReaderSourceAudioStream(
             media_type=media_type,
@@ -134,6 +139,7 @@ def _parse_si(i):
             bit_rate=bit_rate,
             num_frames=num_frames,
             bits_per_sample=bps,
+            metadata=metadata,
             sample_rate=i[_SAMPLE_RATE],
             num_channels=i[_NUM_CHANNELS],
         )
@@ -146,6 +152,7 @@ def _parse_si(i):
             bit_rate=bit_rate,
             num_frames=num_frames,
             bits_per_sample=bps,
+            metadata=metadata,
             width=i[_WIDTH],
             height=i[_HEIGHT],
             frame_rate=i[_FRAME_RATE],
@@ -158,6 +165,7 @@ def _parse_si(i):
         bit_rate=None,
         num_frames=None,
         bits_per_sample=None,
+        metadata=metadata,
     )