+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);
+
+ if (fabs(theta - 90*round(theta/90)) > 2)
+ av_log_ask_for_sample(NULL, "Odd rotation angle\n");
+
+ return theta;
+}
+