register devices before searching in ffpmeg

configure

@@ -7988,6 +7988,7 @@ $as_echo_n "checking for ffmpeg headers... " >&6; }
 		#include <libavcodec/avcodec.h>
 		#include <libavformat/avformat.h>
 		#include <libswscale/swscale.h>
+		#include <libavdevice/avdevice.h>
 		int main(){}
 
 _ACEOF
@@ -8219,6 +8220,53 @@ _ACEOF
 
   LIBS="-lswscale $LIBS"
 
+else
+  a=1
+fi
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for avdevice_register_all in -lavdevice" >&5
+$as_echo_n "checking for avdevice_register_all in -lavdevice... " >&6; }
+if ${ac_cv_lib_avdevice_avdevice_register_all+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lavdevice  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char avdevice_register_all ();
+int
+main ()
+{
+return avdevice_register_all ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_cxx_try_link "$LINENO"; then :
+  ac_cv_lib_avdevice_avdevice_register_all=yes
+else
+  ac_cv_lib_avdevice_avdevice_register_all=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_avdevice_avdevice_register_all" >&5
+$as_echo "$ac_cv_lib_avdevice_avdevice_register_all" >&6; }
+if test "x$ac_cv_lib_avdevice_avdevice_register_all" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBAVDEVICE 1
+_ACEOF
+
+  LIBS="-lavdevice $LIBS"
+
 else
   a=1
 fi

configure.ac

@@ -690,6 +690,7 @@ CHECK_FOR_OPTION(ffmpeg, [
 		#include <libavcodec/avcodec.h>
 		#include <libavformat/avformat.h>
 		#include <libswscale/swscale.h>
+		#include <libavdevice/avdevice.h>
 		int main(){}
 	])], [ ffmpeg_new_headers=1], [])
 
@@ -701,6 +702,7 @@ CHECK_FOR_OPTION(ffmpeg, [
 		AC_CHECK_LIB(avformat, av_read_frame, [ffmpeg_recent=yes], [a=1]) #only in >= 0.4.9
 		AC_CHECK_LIB(avcodec, avcodec_open2, [], [a=1])
 		AC_CHECK_LIB(swscale, sws_getContext, [], [a=1])
+		AC_CHECK_LIB(avdevice, avdevice_register_all, [], [a=1])
 	else
 		a=1
 	fi

cvd_src/videofilebuffer2.cc

@@ -16,6 +16,7 @@ extern "C" {
 #include <libavcodec/avcodec.h>
 #include <libavformat/avformat.h>
 #include <libswscale/swscale.h>
+#include <libavdevice/avdevice.h>
 }
 
 #include <string>
@@ -217,6 +218,7 @@ class RawVideoFileBufferPIMPL
 		{ 
 			av_register_all();
 			avcodec_register_all();
+			avdevice_register_all();
 			DS("starting");
 
 			int r;