Write 8 or 16 audio channels to SMPTE DCP MXFs, as appropriate (#2443).

diff --git a/src/lib/reel_writer.cc b/src/lib/reel_writer.cc
index e8db82fbb26976424fbbab26ef375a6d7ad1f22c..f9a110ed1f136f0b5ae42f7a4201415b1e862185 100644 (file)
--- a/src/lib/reel_writer.cc
+++ b/src/lib/reel_writer.cc
@@ -179,8 +179,7 @@ ReelWriter::ReelWriter (
                _sound_asset = make_shared<dcp::SoundAsset> (
                        dcp::Fraction(film()->video_frame_rate(), 1),
                        film()->audio_frame_rate(),
-                       /* Always make 16-channel sound assets for SMPTE; libdcp will pad unused channels for us */
-                       standard == dcp::Standard::SMPTE ? MAX_DCP_AUDIO_CHANNELS : film()->audio_channels(),
+                       audio_channels_to_write_to_mxf(film()),
                        lang ? *lang : dcp::LanguageTag("en-US"),
                        standard
                        );

diff --git a/src/lib/writer.cc b/src/lib/writer.cc
index 71e9d579dacbc91d078665cbdc7922e9f552993f..573e9da26d3504c46330f2a7f58a8cc37a22a2e3 100644 (file)
--- a/src/lib/writer.cc
+++ b/src/lib/writer.cc
@@ -653,9 +653,12 @@ Writer::finish (boost::filesystem::path output_dcp)
                field = dcp::MCASoundField::FIVE_POINT_ONE;
        }
 
-       dcp::MainSoundConfiguration msc(field, MAX_DCP_AUDIO_CHANNELS);
+       auto const audio_channels = audio_channels_to_write_to_mxf(film());
+       dcp::MainSoundConfiguration msc(field, audio_channels);
        for (auto i: film()->mapped_audio_channels()) {
-               msc.set_mapping(i, static_cast<dcp::Channel>(i));
+               if (i < audio_channels) {
+                       msc.set_mapping(i, static_cast<dcp::Channel>(i));
+               }
        }
 
        cpl->set_main_sound_configuration(msc);

diff --git a/test/ffmpeg_audio_test.cc b/test/ffmpeg_audio_test.cc
index 910fc942c488d4d28a90b53d218eb4bedfaf6dd4..638f9b1e3cb6cd50ad9933fb100b0ad3df2e184b 100644 (file)
--- a/test/ffmpeg_audio_test.cc
+++ b/test/ffmpeg_audio_test.cc
@@ -58,8 +58,10 @@ BOOST_AUTO_TEST_CASE (ffmpeg_audio_test)
 
        BOOST_REQUIRE (!wait_for_jobs());
 
+       int constexpr audio_channels = 8;
+
        film->set_container (Ratio::from_id ("185"));
-       film->set_audio_channels (6);
+       film->set_audio_channels(audio_channels);
        film->set_dcp_content_type (DCPContentType::from_isdcf_name ("TST"));
        make_and_verify_dcp (film);
 
@@ -71,7 +73,7 @@ BOOST_AUTO_TEST_CASE (ffmpeg_audio_test)
 
        auto sound_asset = check.cpls().front()->reels().front()->main_sound ();
        BOOST_CHECK (sound_asset);
-       BOOST_CHECK_EQUAL(sound_asset->asset()->channels (), 16);
+       BOOST_REQUIRE_EQUAL(sound_asset->asset()->channels (), audio_channels);
 
        /* Sample index in the DCP */
        int n = 0;
@@ -82,7 +84,7 @@ BOOST_AUTO_TEST_CASE (ffmpeg_audio_test)
                auto sound_frame = sound_asset->asset()->start_read()->get_frame (frame++);
                uint8_t const * d = sound_frame->data ();
                for (int offset = 0; offset < sound_frame->size(); offset += (3 * sound_asset->asset()->channels())) {
-                       for (auto channel = 0; channel < MAX_DCP_AUDIO_CHANNELS; ++channel) {
+                       for (auto channel = 0; channel < audio_channels; ++channel) {
                                auto const sample = d[offset + channel * 3 + 1] | (d[offset + channel * 3 + 2] << 8);
                                if (channel == 2) {
                                        /* Input should be on centre */