avcodec/mpeg4videodec: Fix default low_delay flag value if not coded

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/mpeg4videodec.c

@@ -1754,9 +1754,17 @@ static int decode_vol_header(Mpeg4DecContext *ctx, GetBitContext *gb)
     } else {
         /* is setting low delay flag only once the smartest thing to do?
          * low delay detection won't be overridden. */
-        if (s->picture_number == 0)
+        if (s->picture_number == 0) {
+            switch(s->vo_type) {
+            case SIMPLE_VO_TYPE:
+            case ADV_SIMPLE_VO_TYPE:
+                s->low_delay = 1;
+                break;
+            default:
                 s->low_delay = 0;
             }
+        }
+    }
 
     ctx->shape = get_bits(gb, 2); /* vol shape */
     if (ctx->shape != RECT_SHAPE)

tests/ref/fate/iv8-demux

@@ -5,27 +5,27 @@
 #dimensions 0: 704x576
 #sar 0: 1/1
 0,          0,          0,        0,    20883, 0x347191e2
-0,          0,       3600,        0,    20882, 0xe1573905
-0,       3600,       7200,        0,    20894, 0xd54f516a
-0,       7200,      10800,        0,    20891, 0x1b5c5039
-0,      10800,      14400,        0,    20883, 0x8e785b4d
-0,      14400,      18000,        0,    20870, 0xd26ca1f6
-0,      18000,      21600,        0,    21448, 0x946f5b2b
-0,      21600,      25200,        0,    21433, 0xb18687c5
-0,      25200,      28800,        0,    20865, 0xc0eb3fce
-0,      28800,      32399,        0,    20842, 0x9d0728ba
-0,      32399,      35999,        0,    20878, 0xf60f5dee
-0,      35999,      39600,        0,    20866, 0x3bde568f
-0,      39600,      43200,        0,    20884, 0x22736993
-0,      43200,      46800,        0,    20860, 0xf56f2fca
-0,      46800,      50400,        0,    20872, 0xf39e3cb3
-0,      50400,      53999,        0,    20835, 0xa3c4363b
-0,      53999,      57600,        0,    20905, 0x552853d1
-0,      57600,      61200,        0,    20874, 0xed0b91ec
-0,      61200,      64799,        0,    20877, 0xe1623e01
-0,      64799,      68399,        0,    20933, 0x19906564
-0,      68399,      72000,        0,    20891, 0x3d064fd3
-0,      72000,      75600,        0,    20834, 0xcb774dbc
-0,      75600,      79200,        0,    20870, 0xbc536589
-0,      79200,      82800,        0,    21421, 0xc99a68e4
-0,      82800,      86400,        0,    12869, 0x5684e304
+0,       3600,       3600,        0,    20882, 0xe1573905
+0,       7200,       7200,        0,    20894, 0xd54f516a
+0,      10800,      10800,        0,    20891, 0x1b5c5039
+0,      14400,      14400,        0,    20883, 0x8e785b4d
+0,      18000,      18000,        0,    20870, 0xd26ca1f6
+0,      21600,      21600,        0,    21448, 0x946f5b2b
+0,      25200,      25200,        0,    21433, 0xb18687c5
+0,      28800,      28800,        0,    20865, 0xc0eb3fce
+0,      32399,      32399,        0,    20842, 0x9d0728ba
+0,      35999,      35999,        0,    20878, 0xf60f5dee
+0,      39600,      39600,        0,    20866, 0x3bde568f
+0,      43200,      43200,        0,    20884, 0x22736993
+0,      46800,      46800,        0,    20860, 0xf56f2fca
+0,      50400,      50400,        0,    20872, 0xf39e3cb3
+0,      53999,      53999,        0,    20835, 0xa3c4363b
+0,      57600,      57600,        0,    20905, 0x552853d1
+0,      61200,      61200,        0,    20874, 0xed0b91ec
+0,      64799,      64799,        0,    20877, 0xe1623e01
+0,      68399,      68399,        0,    20933, 0x19906564
+0,      72000,      72000,        0,    20891, 0x3d064fd3
+0,      75600,      75600,        0,    20834, 0xcb774dbc
+0,      79200,      79200,        0,    20870, 0xbc536589
+0,      82800,      82800,        0,    21421, 0xc99a68e4
+0,      86400,      86400,        0,    12869, 0x5684e304