avdevice/decklink: fix MSVC build issues

Purpose: Made minor changes to get the decklink avdevice code to build
using Visual C++.

Notes: Made changes to configure per Hendrik Leppkes's review of first
and second versions of patch.  Also made slight alterations per Marton
Balint's reviews.

Comments:

-- configure: Added if enabled decklink section and setting
   decklink_indev_extralibs and decklink_outdev_extralibs here for
   both mingw and Windows.  Also eliminated the setting of these
   variables in the mingw section earlier in the file.

-- libavdevice/decklink_common.cpp: Switched the order of the include
   of libavformat/internal.h to workaround build issues with Visual
   C++.  See comment in file for more details.

-- libavdevice/decklink_dec.cpp:
a) Rearranged the include of libavformat/internal.h (for reasons as
   described above).
b) Made slight alteration to an argument for call to av_rescale_q() to
   workaround a compiler error with Visual C++.  This appears to only
   be an issue when building C++ files with Visual C++.  See comment
   in code for more details.

-- libavdevice/decklink_enc.cpp: Rearranged the include of
   libavformat/internal.h (for reasons as described above).

Signed-off-by: Aaron Levinson <alevinsn@aracnet.com>
Signed-off-by: Marton Balint <cus@passwd.hu>

3 files changed, 26 insertions, 4 deletions

diff --git a/libavdevice/decklink_common.cpp b/libavdevice/decklink_common.cpp
index f01fba953e..cbb591ce64 100644
--- a/libavdevice/decklink_common.cpp
+++ b/libavdevice/decklink_common.cpp
@@ -19,6 +19,12 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/* Include internal.h first to avoid conflict between winsock.h (used by
+ * DeckLink headers) and winsock2.h (used by libavformat) in MSVC++ builds */
+extern "C" {
+#include "libavformat/internal.h"
+}
+
 #include <DeckLinkAPI.h>
 #ifdef _WIN32
 #include <DeckLinkAPI_i.c>
@@ -28,7 +34,6 @@
 
 extern "C" {
 #include "libavformat/avformat.h"
-#include "libavformat/internal.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/bswap.h"
diff --git a/libavdevice/decklink_dec.cpp b/libavdevice/decklink_dec.cpp
index 67eaf97e89..39974e3ff4 100644
--- a/libavdevice/decklink_dec.cpp
+++ b/libavdevice/decklink_dec.cpp
@@ -19,12 +19,17 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/* Include internal.h first to avoid conflict between winsock.h (used by
+ * DeckLink headers) and winsock2.h (used by libavformat) in MSVC++ builds */
+extern "C" {
+#include "libavformat/internal.h"
+}
+
 #include <DeckLinkAPI.h>
 
 extern "C" {
 #include "config.h"
 #include "libavformat/avformat.h"
-#include "libavformat/internal.h"
 #include "libavutil/avutil.h"
 #include "libavutil/common.h"
 #include "libavutil/imgutils.h"
@@ -262,8 +267,15 @@ static int64_t get_pkt_pts(IDeckLinkVideoInputFrame *videoFrame,
                 res = videoFrame->GetHardwareReferenceTimestamp(time_base.den, &bmd_pts, &bmd_duration);
             break;
         case PTS_SRC_WALLCLOCK:
-            pts = av_rescale_q(wallclock, AV_TIME_BASE_Q, time_base);
+        {
+            /* MSVC does not support compound literals like AV_TIME_BASE_Q
+             * in C++ code (compiler error C4576) */
+            AVRational timebase;
+            timebase.num = 1;
+            timebase.den = AV_TIME_BASE;
+            pts = av_rescale_q(wallclock, timebase, time_base);
             break;
+        }
     }
     if (res == S_OK)
         pts = bmd_pts / time_base.num;
diff --git a/libavdevice/decklink_enc.cpp b/libavdevice/decklink_enc.cpp
index 5105967101..be01bcd64c 100644
--- a/libavdevice/decklink_enc.cpp
+++ b/libavdevice/decklink_enc.cpp
@@ -22,11 +22,16 @@
 #include <atomic>
 using std::atomic;
 
+/* Include internal.h first to avoid conflict between winsock.h (used by
+ * DeckLink headers) and winsock2.h (used by libavformat) in MSVC++ builds */
+extern "C" {
+#include "libavformat/internal.h"
+}
+
 #include <DeckLinkAPI.h>
 
 extern "C" {
 #include "libavformat/avformat.h"
-#include "libavformat/internal.h"
 #include "libavutil/imgutils.h"
 }