From 41f99ea4da78522f8d3e25619d8e619e4ba7681e Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Fri, 20 Jan 2017 00:44:10 +0100
Subject: [PATCH] Support DeckLink cards that don't have an HDMI connector.

Setting input or output to HDMI on SDI-only cards is an error,
even if HDMI/SDI generally outputs to both on combined cards.
---
 decklink_capture.cpp |  4 +++-
 decklink_output.cpp  | 10 +++++++---
 decklink_output.h    |  1 +
 decklink_util.cpp    | 42 ++++++++++++++++++++++++++++++++++++++++++
 decklink_util.h      |  3 +++
 5 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/decklink_capture.cpp b/decklink_capture.cpp
index 2c25520..892660d 100644
--- a/decklink_capture.cpp
+++ b/decklink_capture.cpp
@@ -213,7 +213,9 @@ DeckLinkCapture::DeckLinkCapture(IDeckLink *card, int card_index)
 		exit(1);
 	}
 
-	set_video_input(bmdVideoConnectionHDMI);
+	BMDVideoConnection connection = pick_default_video_connection(card, BMDDeckLinkVideoInputConnections, card_index);
+
+	set_video_input(connection);
 	set_audio_input(bmdAudioConnectionEmbedded);
 
 	IDeckLinkDisplayModeIterator *mode_it;
diff --git a/decklink_output.cpp b/decklink_output.cpp
index 46d9b14..7fa689e 100644
--- a/decklink_output.cpp
+++ b/decklink_output.cpp
@@ -52,6 +52,12 @@ void DeckLinkOutput::set_device(IDeckLink *decklink)
 	}
 
 	mode_it->Release();
+
+	// HDMI or SDI generally mean “both HDMI and SDI at the same time” on DeckLink cards
+	// that support both; pick_default_video_connection() will generally pick one of those
+	// if they exist. We're not very likely to need analog outputs, so we don't need a way
+	// to change beyond that.
+	video_connection = pick_default_video_connection(decklink, BMDDeckLinkVideoOutputConnections, card_index);
 }
 
 void DeckLinkOutput::start_output(uint32_t mode, int64_t base_pts)
@@ -71,9 +77,7 @@ void DeckLinkOutput::start_output(uint32_t mode, int64_t base_pts)
 		fprintf(stderr, "Failed to set low latency output\n");
 		exit(1);
 	}
-	// HDMI or SDI generally mean “both HDMI and SDI at the same time” on DeckLink cards.
-	// We're not very likely to need analog outputs.
-	if (config->SetInt(bmdDeckLinkConfigVideoOutputConnection, bmdVideoConnectionHDMI) != S_OK) {
+	if (config->SetInt(bmdDeckLinkConfigVideoOutputConnection, video_connection) != S_OK) {
 		fprintf(stderr, "Failed to set video output connection for card %u\n", card_index);
 		exit(1);
 	}
diff --git a/decklink_output.h b/decklink_output.h
index 0aba506..0545bb7 100644
--- a/decklink_output.h
+++ b/decklink_output.h
@@ -122,6 +122,7 @@ private:
 
 	movit::ResourcePool *resource_pool;
 	IDeckLinkOutput *output = nullptr;
+	BMDVideoConnection video_connection;
 	QSurface *surface;
 	unsigned width, height;
 	unsigned card_index;
diff --git a/decklink_util.cpp b/decklink_util.cpp
index 0e775de..a6bdfd9 100644
--- a/decklink_util.cpp
+++ b/decklink_util.cpp
@@ -1,6 +1,8 @@
 #include <DeckLinkAPI.h>
 #include <DeckLinkAPIModes.h>
 
+#include <assert.h>
+
 #include "decklink_util.h"
 
 using namespace bmusb;
@@ -43,3 +45,43 @@ map<uint32_t, VideoMode> summarize_video_modes(IDeckLinkDisplayModeIterator *mod
 
 	return video_modes;
 }
+
+BMDVideoConnection pick_default_video_connection(IDeckLink *card, BMDDeckLinkAttributeID attribute_id, unsigned card_index)
+{
+	assert(attribute_id == BMDDeckLinkVideoInputConnections ||
+	       attribute_id == BMDDeckLinkVideoOutputConnections);
+
+	IDeckLinkAttributes *attr;
+	if (card->QueryInterface(IID_IDeckLinkAttributes, (void**)&attr) != S_OK) {
+		fprintf(stderr, "Card %u has no attributes\n", card_index);
+		exit(1);
+	}
+
+	int64_t connection_mask;
+	if (attr->GetInt(attribute_id, &connection_mask) != S_OK) {
+		if (attribute_id == BMDDeckLinkVideoInputConnections) {
+			fprintf(stderr, "Failed to enumerate video inputs for card %u\n", card_index);
+		} else {
+			fprintf(stderr, "Failed to enumerate video outputs for card %u\n", card_index);
+		}
+		exit(1);
+	}
+	attr->Release();
+	if (connection_mask == 0) {
+		if (attribute_id == BMDDeckLinkVideoInputConnections) {
+			fprintf(stderr, "Card %u has no input connections\n", card_index);
+		} else {
+			fprintf(stderr, "Card %u has no outpu connectionss\n", card_index);
+		}
+		exit(1);
+	}
+
+	if (connection_mask & bmdVideoConnectionHDMI) {
+		return bmdVideoConnectionHDMI;
+	} else if (connection_mask & bmdVideoConnectionSDI) {
+		return bmdVideoConnectionSDI;
+	} else {
+		// Fallback: Return lowest-set bit, whatever that might be.
+		return connection_mask & (-connection_mask);
+	}
+}
diff --git a/decklink_util.h b/decklink_util.h
index 2bef415..2850a21 100644
--- a/decklink_util.h
+++ b/decklink_util.h
@@ -11,4 +11,7 @@ class IDeckLinkDisplayModeIterator;
 
 std::map<uint32_t, bmusb::VideoMode> summarize_video_modes(IDeckLinkDisplayModeIterator *mode_it, unsigned card_index);
 
+// Picks a video connection that the card supports. Priority list: HDMI, SDI, anything else.
+BMDVideoConnection pick_default_video_connection(IDeckLink *card, BMDDeckLinkAttributeID attribute_id, unsigned card_index);
+
 #endif  // !defined(_DECKLINK_UTIL)
-- 
2.39.2