Allow specification of channels that need a MCASubDescriptor.

[libdcp.git] / src / sound_asset_writer.cc

diff --git a/src/sound_asset_writer.cc b/src/sound_asset_writer.cc
index 0300407cd101f0c002cc841b2bda24c5399234fd..1185616a30927be43af82d63e19dcaa108ef7ac2 100644 (file)
--- a/src/sound_asset_writer.cc
+++ b/src/sound_asset_writer.cc
@@ -69,16 +69,36 @@ struct SoundAssetWriter::ASDCPState
 };
 
 
-SoundAssetWriter::SoundAssetWriter (SoundAsset* asset, boost::filesystem::path file, bool sync, bool include_mca_subdescriptors)
+SoundAssetWriter::SoundAssetWriter(SoundAsset* asset, boost::filesystem::path file, vector<dcp::Channel> extra_active_channels, bool sync, bool include_mca_subdescriptors)
        : AssetWriter (asset, file)
        , _state (new SoundAssetWriter::ASDCPState)
        , _asset (asset)
+       , _extra_active_channels(extra_active_channels)
        , _sync (sync)
        , _include_mca_subdescriptors(include_mca_subdescriptors)
 {
        DCP_ASSERT (!_sync || _asset->channels() >= 14);
        DCP_ASSERT (!_sync || _asset->standard() == Standard::SMPTE);
 
+       /* None of these are allowed in extra_active_channels; some are implicit, and (it seems) should never have a descriptor
+        * written for them.
+        */
+       vector<Channel> disallowed_extra = {
+               Channel::LEFT,
+               Channel::RIGHT,
+               Channel::CENTRE,
+               Channel::LFE,
+               Channel::LS,
+               Channel::RS,
+               Channel::MOTION_DATA,
+               Channel::SYNC_SIGNAL,
+               Channel::SIGN_LANGUAGE,
+               Channel::CHANNEL_COUNT
+       };
+       for (auto disallowed: disallowed_extra) {
+               DCP_ASSERT(std::find(extra_active_channels.begin(), extra_active_channels.end(), disallowed) == extra_active_channels.end());
+       }
+
        /* Derived from ASDCP::Wav::SimpleWaveHeader::FillADesc */
        _state->desc.EditRate = ASDCP::Rational (_asset->edit_rate().numerator, _asset->edit_rate().denominator);
        _state->desc.AudioSamplingRate = ASDCP::Rational (_asset->sampling_rate(), 1);
@@ -146,7 +166,11 @@ SoundAssetWriter::start ()
                        soundfield->RFC5646SpokenLanguage = *lang;
                }
 
-               const MCASoundField field = _asset->channels() > 10 ? MCASoundField::SEVEN_POINT_ONE : MCASoundField::FIVE_POINT_ONE;
+               MCASoundField const field =
+                       (
+                               find(_extra_active_channels.begin(), _extra_active_channels.end(), dcp::Channel::BSL) != _extra_active_channels.end() ||
+                               find(_extra_active_channels.begin(), _extra_active_channels.end(), dcp::Channel::BSR) != _extra_active_channels.end()
+                       ) ? MCASoundField::SEVEN_POINT_ONE : MCASoundField::FIVE_POINT_ONE;
 
                if (field == MCASoundField::SEVEN_POINT_ONE) {
                        soundfield->MCATagSymbol = "sg71";
@@ -165,22 +189,25 @@ LIBDCP_ENABLE_WARNINGS
                _state->mxf_writer.OP1aHeader().AddChildObject(soundfield);
                essence_descriptor->SubDescriptors.push_back(soundfield->InstanceUID);
 
-               /* 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;
-                       }
+               std::vector<dcp::Channel> dcp_channels = {
+                       Channel::LEFT,
+                       Channel::RIGHT,
+                       Channel::CENTRE,
+                       Channel::LFE,
+                       Channel::LS,
+                       Channel::RS
+               };
+
+               std::copy(_extra_active_channels.begin(), _extra_active_channels.end(), back_inserter(dcp_channels));
+               std::sort(dcp_channels.begin(), dcp_channels.end());
+               auto last = std::unique(dcp_channels.begin(), dcp_channels.end());
+               dcp_channels.erase(last, dcp_channels.end());
+
+               for (auto dcp_channel: dcp_channels) {
                        auto channel = new ASDCP::MXF::AudioChannelLabelSubDescriptor(asdcp_smpte_dict);
                        GenRandomValue (channel->MCALinkID);
                        channel->SoundfieldGroupLinkID = soundfield->MCALinkID;
-                       channel->MCAChannelID = i + 1;
+                       channel->MCAChannelID = static_cast<int>(dcp_channel) + 1;
                        channel->MCATagSymbol = "ch" + channel_to_mca_id(dcp_channel, field);
                        channel->MCATagName = channel_to_mca_name(dcp_channel, field);
                        if (auto lang = _asset->language()) {