avformat/matroskaenc: write DisplayWidth and DisplayHeight elements only if they differ from PixelWidth and PixelHeight

Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/matroskaenc.c

@@ -1192,8 +1192,10 @@ static int mkv_write_track(AVFormatContext *s, MatroskaMuxContext *mkv,
                 av_log(s, AV_LOG_ERROR, "Overflow in display width\n");
                 return AVERROR(EINVAL);
             }
-            put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , d_width / display_width_div);
-            put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, par->height / display_height_div);
+            if (d_width != par->width || display_width_div != 1 || display_height_div != 1) {
+                put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , d_width / display_width_div);
+                put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, par->height / display_height_div);
+            }
         } else if (display_width_div != 1 || display_height_div != 1) {
             put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , par->width / display_width_div);
             put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, par->height / display_height_div);

tests/fate/matroska.mak

@@ -4,6 +4,6 @@
 FATE_MATROSKA-$(call DEMMUX, MATROSKA, MATROSKA) += fate-matroska-remux
 fate-matroska-remux: CMD = md5 -i $(TARGET_SAMPLES)/vp9-test-vectors/vp90-2-2pass-akiyo.webm -color_trc 4 -c:v copy -fflags +bitexact -strict -2 -f matroska
 fate-matroska-remux: CMP = oneline
-fate-matroska-remux: REF = 84e950f59677e306f944fca484888c5d
+fate-matroska-remux: REF = 9b8398b42804ba12c39d2f47299a0996
 
 FATE_SAMPLES_AVCONV += $(FATE_MATROSKA-yes)