Write MCA tags based on the specified sound field.

[libdcp.git] / src / sound_asset_writer.cc

diff --git a/src/sound_asset_writer.cc b/src/sound_asset_writer.cc
index c0cdf0cbb7beaf59f5ef9eb09df3a8d5f10f19a3..205a45ab2f9c2eb25e8d62dcad1795ff73fb5598 100644 (file)
--- a/src/sound_asset_writer.cc
+++ b/src/sound_asset_writer.cc
@@ -66,12 +66,11 @@ struct SoundAssetWriter::ASDCPState
 };
 
 
-SoundAssetWriter::SoundAssetWriter (SoundAsset* asset, boost::filesystem::path file, vector<Channel> active_channels, bool sync)
+SoundAssetWriter::SoundAssetWriter (SoundAsset* asset, boost::filesystem::path file, bool sync)
        : AssetWriter (asset, file)
        , _state (new SoundAssetWriter::ASDCPState)
        , _asset (asset)
        , _sync (sync)
-       , _active_channels (active_channels)
 {
        DCP_ASSERT (!_sync || _asset->channels() >= 14);
        DCP_ASSERT (!_sync || _asset->standard() == Standard::SMPTE);
@@ -117,7 +116,7 @@ SoundAssetWriter::start ()
                boost::throw_exception (FileError("could not open audio MXF for writing", _file.string(), r));
        }
 
-       if (_asset->standard() == Standard::SMPTE && !_active_channels.empty()) {
+       if (_asset->standard() == Standard::SMPTE) {
 
                ASDCP::MXF::WaveAudioDescriptor* essence_descriptor = nullptr;
                _state->mxf_writer.OP1aHeader().GetMDObjectByType(
@@ -145,15 +144,26 @@ SoundAssetWriter::start ()
                _state->mxf_writer.OP1aHeader().AddChildObject(soundfield);
                essence_descriptor->SubDescriptors.push_back(soundfield->InstanceUID);
 
-               for (auto i: _active_channels) {
+               /* We must describe at least the number of channels in `field', even if they aren't
+                * in the asset (I think)
+                */
+               int descriptors = max(_asset->channels(), field == MCASoundField::FIVE_POINT_ONE ? 6 : 8);
+
+               auto const used = used_audio_channels();
+
+               for (auto i = 0; i < descriptors; ++i) {
+                       auto dcp_channel = static_cast<dcp::Channel>(i);
+                       if (find(used.begin(), used.end(), dcp_channel) == used.end()) {
+                               continue;
+                       }
                        auto channel = new ASDCP::MXF::AudioChannelLabelSubDescriptor(asdcp_smpte_dict);
                        GenRandomValue (channel->MCALinkID);
                        channel->SoundfieldGroupLinkID = soundfield->MCALinkID;
-                       channel->MCAChannelID = static_cast<int>(i) + 1;
-                       channel->MCATagSymbol = "ch" + channel_to_mca_id(i, field);
-                       channel->MCATagName = channel_to_mca_name(i, field);
+                       channel->MCAChannelID = i + 1;
+                       channel->MCATagSymbol = "ch" + channel_to_mca_id(dcp_channel, field);
+                       channel->MCATagName = channel_to_mca_name(dcp_channel, field);
                        channel->RFC5646SpokenLanguage = _asset->language();
-                       channel->MCALabelDictionaryID = channel_to_mca_universal_label(i, field, asdcp_smpte_dict);
+                       channel->MCALabelDictionaryID = channel_to_mca_universal_label(dcp_channel, field, asdcp_smpte_dict);
                        _state->mxf_writer.OP1aHeader().AddChildObject(channel);
                        essence_descriptor->SubDescriptors.push_back(channel->InstanceUID);
                }