Add --audio-channels option to dcpomatic2_create (#2966).

3 files changed, 58 insertions, 11 deletions

diff --git a/src/lib/create_cli.cc b/src/lib/create_cli.cc
index c2378e603..f726aa0ae 100644
--- a/src/lib/create_cli.cc
+++ b/src/lib/create_cli.cc
@@ -58,6 +58,7 @@ string CreateCLI::_help =
 	"      --config <dir>            directory containing config.xml and cinemas.sqlite3\n"
 	"      --twok                    make a 2K DCP instead of choosing a resolution based on the content\n"
 	"      --fourk                   make a 4K DCP instead of choosing a resolution based on the content\n"
+	"  -a, --audio-channels <n>      specify the number of audio channels in the DCP\n"
 	"  -o, --output <dir>            output directory\n"
 	"      --twod                    make a 2D DCP\n"
 	"      --threed                  make a 3D DCP\n"
@@ -154,6 +155,7 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 	int dcp_frame_rate_int = 0;
 	string template_name_string;
 	int64_t video_bit_rate_int = 0;
+	optional<int> audio_channels;
 	auto next_frame_type = VideoFrameType::TWO_D;
 	optional<dcp::Channel> channel;
 	optional<float> gain;
@@ -227,6 +229,7 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 		argument_option(i, argc, argv, "",   "--config",           &claimed, &error, &config_dir, string_to_path);
 		argument_option(i, argc, argv, "-o", "--output",           &claimed, &error, &output_dir, string_to_path);
 		argument_option(i, argc, argv, "",   "--video-bit-rate",   &claimed, &error, &video_bit_rate_int);
+		argument_option(i, argc, argv, "-a", "--audio-channels",   &claimed, &error, &audio_channels);
 
 		std::function<optional<dcp::Channel> (string)> convert_channel = [](string channel) -> optional<dcp::Channel>{
 			if (channel == "L") {
@@ -346,6 +349,34 @@ CreateCLI::CreateCLI (int argc, char* argv[])
 		error = String::compose("%1: video-bit-rate must be between 10 and %2 Mbit/s", argv[0], (Config::instance()->maximum_video_bit_rate(VideoEncoding::JPEG2000) / 1000000));
 		return;
 	}
+
+	/* See how many audio channels we would need to accommmodate the requested channel mappings */
+	int channels_for_content_specs = 0;
+	for (auto cli_content: content) {
+		if (cli_content.channel) {
+			channels_for_content_specs = std::max(channels_for_content_specs, static_cast<int>(*cli_content.channel) + 1);
+		}
+	}
+
+	/* Complain if we asked for a smaller number */
+	if (audio_channels && *audio_channels < channels_for_content_specs) {
+		error = fmt::format("{}: cannot map audio as requested with only {} channels", argv[0], *audio_channels);
+		return;
+	}
+
+	if (audio_channels && (*audio_channels % 2) != 0) {
+		error = fmt::format("{}: audio channel count must be even", argv[0]);
+		return;
+	}
+
+	if (audio_channels) {
+		_audio_channels = *audio_channels;
+	} else {
+		_audio_channels = std::max(channels_for_content_specs, 6);
+		if (_audio_channels % 2) {
+			++_audio_channels;
+		}
+	}
 }
 
 
@@ -398,17 +429,7 @@ CreateCLI::make_film() const
 		film->set_video_bit_rate(VideoEncoding::JPEG2000, *_video_bit_rate);
 	}
 
-	int channels = 6;
-	for (auto cli_content: content) {
-		if (cli_content.channel) {
-			channels = std::max(channels, static_cast<int>(*cli_content.channel) + 1);
-		}
-	}
-	if (channels % 2) {
-		++channels;
-	}
-
-	film->set_audio_channels(channels);
+	film->set_audio_channels(_audio_channels);
 
 	return film;
 }
diff --git a/src/lib/create_cli.h b/src/lib/create_cli.h
index 850cddea9..18115b4ca 100644
--- a/src/lib/create_cli.h
+++ b/src/lib/create_cli.h
@@ -73,6 +73,7 @@ private:
 	bool _twok = false;
 	bool _fourk = false;
 	boost::optional<int64_t> _video_bit_rate;
+	int _audio_channels = 0;
 
 	static std::string _help;
 };
diff --git a/test/create_cli_test.cc b/test/create_cli_test.cc
index 7006fa6a0..ac184203d 100644
--- a/test/create_cli_test.cc
+++ b/test/create_cli_test.cc
@@ -196,6 +196,8 @@ BOOST_AUTO_TEST_CASE (create_cli_test)
 	BOOST_CHECK (*cc.content[1].channel == dcp::Channel::RIGHT);
 	BOOST_CHECK_EQUAL (cc.content[2].path, "sheila.wav");
 	BOOST_CHECK (!cc.content[2].channel);
+	auto film = cc.make_film();
+	BOOST_CHECK_EQUAL(film->audio_channels(), 6);
 
 	cc = run ("dcpomatic2_create --channel foo fred.wav");
 	BOOST_REQUIRE (cc.error);
@@ -219,6 +221,29 @@ BOOST_AUTO_TEST_CASE (create_cli_test)
 	cc = run("dcpomatic2_create -s SMPTE sheila.wav");
 	BOOST_CHECK(!cc.still_length);
 	BOOST_CHECK(cc.error);
+
+	cc = run("dcpomatic2_create --channel L fred.wav --channel R jim.wav --channel C sheila.wav --audio-channels 2");
+	BOOST_REQUIRE(cc.error);
+	BOOST_CHECK_EQUAL(*cc.error, "dcpomatic2_create: cannot map audio as requested with only 2 channels");
+
+	cc = run("dcpomatic2_create --channel L fred.wav --channel R jim.wav --channel C sheila.wav --audio-channels 3");
+	BOOST_REQUIRE(cc.error);
+	BOOST_CHECK_EQUAL(*cc.error, "dcpomatic2_create: audio channel count must be even");
+
+	cc = run("dcpomatic2_create --channel L fred.wav --channel R jim.wav --channel C sheila.wav");
+	BOOST_CHECK(!cc.error);
+	film = cc.make_film();
+	BOOST_CHECK_EQUAL(film->audio_channels(), 6);
+
+	cc = run("dcpomatic2_create --channel L fred.wav --channel R jim.wav --channel HI sheila.wav");
+	BOOST_CHECK(!cc.error);
+	film = cc.make_film();
+	BOOST_CHECK_EQUAL(film->audio_channels(), 8);
+
+	cc = run("dcpomatic2_create --channel L fred.wav --channel R jim.wav --channel C sheila.wav --audio-channels 16");
+	BOOST_CHECK(!cc.error);
+	film = cc.make_film();
+	BOOST_CHECK_EQUAL(film->audio_channels(), 16);
 }