decklink: Add option to activate async compensation

Since the audio from the device is asynchronous, it requires to be
compensated so that the audio source provides exactly necessary amount
of samples.
The option is enabled by default.

plugins/decklink/const.h

@@ -14,6 +14,7 @@
 #define KEYER "keyer"
 #define SWAP "swap"
 #define ALLOW_10_BIT "allow_10_bit"
+#define ASYNC_COMPENSATION "async_compensation"
 
 #define TEXT_DEVICE obs_module_text("Device")
 #define TEXT_VIDEO_CONNECTION obs_module_text("VideoConnection")
@@ -57,3 +58,4 @@
 #define TEXT_SWAP obs_module_text("SwapFC-LFE")
 #define TEXT_SWAP_TOOLTIP obs_module_text("SwapFC-LFE.Tooltip")
 #define TEXT_ALLOW_10_BIT obs_module_text("Allow10Bit")
+#define TEXT_ASYNC_COMPENSATION obs_module_text("AsyncCompensation")

plugins/decklink/data/locale/en-US.ini

@@ -39,4 +39,5 @@ SwapFC-LFE="Swap FC and LFE"
 SwapFC-LFE.Tooltip="Swap Front Center Channel and LFE Channel"
 VideoConnection="Video Connection"
 AudioConnection="Audio Connection"
-Allow10Bit="Allow 10 Bit (Required for SDI captions, may cause performance overhead)"
+Allow10Bit="Allow 10 Bit (Required for SDI captions, may cause performance overhead)"
+AsyncCompensation="Enable Asynchronous Compensation"

plugins/decklink/decklink-source.cpp

@@ -76,6 +76,10 @@ static void decklink_update(void *data, obs_data_t *settings)
 	decklink->swap = obs_data_get_bool(settings, SWAP);
 	decklink->allow10Bit = obs_data_get_bool(settings, ALLOW_10_BIT);
 	decklink->Activate(device, id, videoConnection, audioConnection);
+
+	obs_source_set_async_compensation(
+		decklink->GetSource(),
+		obs_data_get_bool(settings, ASYNC_COMPENSATION));
 }
 
 static void decklink_show(void *data)
@@ -106,6 +110,7 @@ static void decklink_get_defaults(obs_data_t *settings)
 	obs_data_set_default_int(settings, COLOR_RANGE, VIDEO_RANGE_DEFAULT);
 	obs_data_set_default_int(settings, CHANNEL_FORMAT, SPEAKERS_STEREO);
 	obs_data_set_default_bool(settings, SWAP, false);
+	obs_data_set_default_bool(settings, ASYNC_COMPENSATION, true);
 }
 
 static const char *decklink_get_name(void *)
@@ -399,6 +404,9 @@ static obs_properties_t *decklink_get_properties(void *data)
 
 	obs_properties_add_bool(props, ALLOW_10_BIT, TEXT_ALLOW_10_BIT);
 
+	obs_properties_add_bool(props, ASYNC_COMPENSATION,
+				TEXT_ASYNC_COMPENSATION);
+
 	UNUSED_PARAMETER(data);
 	return props;
 }