Add SoundAsset::active_channels().v1.8.72

2 files changed, 25 insertions, 3 deletions

diff --git a/src/sound_asset.cc b/src/sound_asset.cc
index 7c94b549..ea952c35 100644
--- a/src/sound_asset.cc
+++ b/src/sound_asset.cc
@@ -104,6 +104,16 @@ SoundAsset::SoundAsset (boost::filesystem::path file)
 		}
 	}
 
+	list<ASDCP::MXF::InterchangeObject*> channel_labels;
+	rr = reader.OP1aHeader().GetMDObjectsByType(
+		asdcp_smpte_dict->ul(ASDCP::MDD_AudioChannelLabelSubDescriptor),
+		channel_labels
+		);
+
+	if (KM_SUCCESS(rr)) {
+		_active_channels = channel_labels.size();
+	}
+
 	_id = read_writer_info (info);
 }
 
@@ -266,3 +276,11 @@ SoundAsset::valid_mxf (boost::filesystem::path file)
 	Kumu::Result_t r = reader.OpenRead (file.string().c_str());
 	return !ASDCP_FAILURE (r);
 }
+
+
+int
+SoundAsset::active_channels() const
+{
+	return _active_channels.get_value_or(_channels);
+}
+
diff --git a/src/sound_asset.h b/src/sound_asset.h
index 55669c2f..70c3aee7 100644
--- a/src/sound_asset.h
+++ b/src/sound_asset.h
@@ -103,11 +103,14 @@ public:
 		NoteHandler note
 		) const override;
 
-	/** @return number of channels */
+	/** @return number of channels in the MXF */
 	int channels () const {
 		return _channels;
 	}
 
+	/** @return An estimate of the number of channels that are actually in use */
+	int active_channels() const;
+
 	/** @return sampling rate in Hz */
 	int sampling_rate () const {
 		return _sampling_rate;
@@ -143,8 +146,9 @@ private:
 	 *  content presented may be less than this.
 	 */
 	int64_t _intrinsic_duration = 0;
-	int _channels = 0;      ///< number of channels
-	int _sampling_rate = 0; ///< sampling rate in Hz
+	int _channels = 0;                     ///< number of channels in the MXF
+	boost::optional<int> _active_channels; ///< estimate of the number of active channels
+	int _sampling_rate = 0;                ///< sampling rate in Hz
 	boost::optional<std::string> _language;
 };