ffplay&cmdutils:Factor get_rotation() code out

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

cmdutils.c

@@ -41,6 +41,7 @@
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
+#include "libavutil/display.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/parseutils.h"
@@ -2229,4 +2230,26 @@ int show_sinks(void *optctx, const char *opt, const char *arg)
     av_log_set_level(error_level);
     return ret;
 }
+
+double get_rotation(AVStream *st)
+{
+    AVDictionaryEntry *rotate_tag = av_dict_get(st->metadata, "rotate", NULL, 0);
+    uint8_t* displaymatrix = av_stream_get_side_data(st,
+                                                     AV_PKT_DATA_DISPLAYMATRIX, NULL);
+    double theta = 0;
+
+    if (rotate_tag && *rotate_tag->value && strcmp(rotate_tag->value, "0")) {
+        char *tail;
+        theta = av_strtod(rotate_tag->value, &tail);
+        if (*tail)
+            theta = 0;
+    }
+    if (displaymatrix && !theta)
+        theta = av_display_rotation_get((int32_t*) displaymatrix);
+
+    theta -= 360*floor(theta/360 + 0.9/360);
+
+    return theta;
+}
+
 #endif