avformat/mxfdec: Offload allocating string to av_dict_set()

Reviewed-by: Tomas Härdin <tjoppen@acc.umu.se>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/mxfdec.c

@@ -2118,16 +2118,12 @@ static int mxf_is_intra_only(MXFDescriptor *descriptor)
                             &descriptor->essence_codec_ul)->id     != AV_CODEC_ID_NONE;
 }
 
-static int mxf_umid_to_str(UID ul, UID uid, char **str)
+static void mxf_umid_to_str(const UID ul, const UID uid,
+                            char str[2 + sizeof(UID) * 4 + 1])
 {
-    char *p;
-    p = *str = av_mallocz(sizeof(UID) * 4 + 2 + 1);
-    if (!p)
-        return AVERROR(ENOMEM);
-    snprintf(p, 2 + 1, "0x");
-    ff_data_to_hex(p + 2, ul, sizeof(UID), 0);
-    ff_data_to_hex(p + 2 + 2 * sizeof(UID), uid, sizeof(UID), 0);
-    return 0;
+    snprintf(str, 2 + sizeof(UID) * 4 + 1, "0x");
+    ff_data_to_hex(str + 2, ul, sizeof(UID), 0);
+    ff_data_to_hex(str + 2 + 2 * sizeof(UID), uid, sizeof(UID), 0);
 }
 
 static int mxf_version_to_str(uint16_t major, uint16_t minor, uint16_t tertiary,
@@ -2141,13 +2137,11 @@ static int mxf_version_to_str(uint16_t major, uint16_t minor, uint16_t tertiary,
 
 static int mxf_add_umid_metadata(AVDictionary **pm, const char *key, MXFPackage* package)
 {
-    char *str;
-    int ret;
+    char str[2 + 4 * sizeof(UID) + 1];
     if (!package)
         return 0;
-    if ((ret = mxf_umid_to_str(package->package_ul, package->package_uid, &str)) < 0)
-        return ret;
-    av_dict_set(pm, key, str, AV_DICT_DONT_STRDUP_VAL);
+    mxf_umid_to_str(package->package_ul, package->package_uid, str);
+    av_dict_set(pm, key, str, 0);
     return 0;
 }