mov: Correctly store dref paths

Rather than reading the alternate absolute path version from dref
type 18, make sure that 0s are considered as '/'. These values are
sometimes present in the full path, and are mistakenly interpreted as
line terminators othewise.

With the correct handling of this dref type, parsing type 18 is not
needed any more.

libavformat/mov.c

@@ -538,7 +538,7 @@ static int mov_read_dref(MOVContext *c, AVIOContext *pb, MOVAtom atom)
                 av_log(c->fc, AV_LOG_DEBUG, "type %d, len %d\n", type, len);
                 if (len&1)
                     len += 1;
-                if (type == 2 || type == 18) { // absolute path
+                if (type == 2) { // absolute path
                     av_free(dref->path);
                     dref->path = av_mallocz(len+1);
                     if (!dref->path)
@@ -549,15 +549,13 @@ static int mov_read_dref(MOVContext *c, AVIOContext *pb, MOVAtom atom)
                         av_freep(&dref->path);
                         return ret;
                     }
-                    if (type == 18) // no additional processing needed
-                        continue;
                     if (len > volume_len && !strncmp(dref->path, dref->volume, volume_len)) {
                         len -= volume_len;
                         memmove(dref->path, dref->path+volume_len, len);
                         dref->path[len] = 0;
                     }
                     for (j = 0; j < len; j++)
-                        if (dref->path[j] == ':')
+                        if (dref->path[j] == ':' || dref->path[j] == 0)
                             dref->path[j] = '/';
                     av_log(c->fc, AV_LOG_DEBUG, "path %s\n", dref->path);
                 } else if (type == 0) { // directory name