avfilter/f_metadata: update print output header line format

Update print mode output header line format to be more consistent with
other log output of FFmpeg. The printf-modifiers have been inspired by
the showinfo filter.
Signed-off-by: Tobias Rapp <t.rapp@noa-archive.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavfilter/f_metadata.c

@@ -306,15 +306,15 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
         break;
     case METADATA_PRINT:
         if (!s->key && e) {
-            s->print(ctx, "frame %"PRId64" pts %"PRId64" pts_time %s\n",
-                     inlink->frame_count, frame->pts, av_ts2timestr(frame->pts, &inlink->time_base));
+            s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%-7s\n",
+                     inlink->frame_count, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));
             s->print(ctx, "%s=%s\n", e->key, e->value);
             while ((e = av_dict_get(metadata, "", e, AV_DICT_IGNORE_SUFFIX)) != NULL) {
                 s->print(ctx, "%s=%s\n", e->key, e->value);
             }
         } else if (e && e->value && (!s->value || (e->value && s->compare(s, e->value, s->value)))) {
-            s->print(ctx, "frame %"PRId64" pts %"PRId64" pts_time %s\n",
-                     inlink->frame_count, frame->pts, av_ts2timestr(frame->pts, &inlink->time_base));
+            s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%-7s\n",
+                     inlink->frame_count, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));
             s->print(ctx, "%s=%s\n", s->key, e->value);
         }
         return ff_filter_frame(outlink, frame);