avformat/apetag: fix flag value to signal footer presence

According to the spec[1], a value of 0 means the footer is present and a value
of 1 means it's absent, the exact opposite of header presence flag where 1
means present and 0 absent.
The reason for this is compatibility with APEv1 tags, where there's no header,
footer presence was mandatory for all files, and the flags field was a zeroed
reserved field.

[1] http://wiki.hydrogenaud.io/index.php?title=Ape_Tags_Flags

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>

libavformat/apetag.c

@@ -30,7 +30,7 @@
 #include "internal.h"
 
 #define APE_TAG_FLAG_CONTAINS_HEADER  (1 << 31)
-#define APE_TAG_FLAG_CONTAINS_FOOTER  (1 << 30)
+#define APE_TAG_FLAG_LACKS_FOOTER     (1 << 30)
 #define APE_TAG_FLAG_IS_HEADER        (1 << 29)
 #define APE_TAG_FLAG_IS_BINARY        (1 << 1)
 
@@ -189,8 +189,7 @@ int ff_ape_write_tag(AVFormatContext *s)
         goto end;
 
     // flags
-    avio_wl32(dyn_bc, APE_TAG_FLAG_CONTAINS_HEADER | APE_TAG_FLAG_CONTAINS_FOOTER |
+    avio_wl32(dyn_bc, APE_TAG_FLAG_CONTAINS_HEADER | APE_TAG_FLAG_IS_HEADER);
-                     APE_TAG_FLAG_IS_HEADER);
     ffio_fill(dyn_bc, 0, 8);             // reserved
 
     ff_standardize_creation_time(s);
@@ -232,7 +231,7 @@ int ff_ape_write_tag(AVFormatContext *s)
     avio_wl32(s->pb, count);            // tag count
 
     // flags
-    avio_wl32(s->pb, APE_TAG_FLAG_CONTAINS_HEADER | APE_TAG_FLAG_CONTAINS_FOOTER);
+    avio_wl32(s->pb, APE_TAG_FLAG_CONTAINS_HEADER);
     ffio_fill(s->pb, 0, 8);             // reserved
 
 end:

tests/ref/lavf/tta

@@ -1,3 +1,3 @@
-f2721d06704ac43d89fdd25835b43598 *./tests/data/lavf/lavf.tta
+d86c5cccb2554143d34d1786ab460a31 *./tests/data/lavf/lavf.tta
 43200 ./tests/data/lavf/lavf.tta
 ./tests/data/lavf/lavf.tta CRC=0x3a1da17e