diff --git a/doc/APIchanges b/doc/APIchanges
index a1e81808e7..d4362c1b56 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -144,6 +144,9 @@ API changes, most recent first:
 2012-03-26 - a67d9cf - lavfi 2.66.100
   Add avfilter_fill_frame_from_{audio_,}buffer_ref() functions.
 
+2013-xx-xx - xxxxxxx - lavu 52.8.0 - avstring.h
+  Add av_isdigit, av_isgraph, av_isspace, av_isxdigit.
+
 2013-xx-xx - xxxxxxx - lavfi 3.4.0 - avfiltergraph.h
   Add resample_lavr_opts to AVFilterGraph for setting libavresample options
   for auto-inserted resample filters.
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 9aec72a8cc..72450decfd 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -2777,10 +2777,10 @@ int avpriv_unlock_avformat(void)
 
 unsigned int avpriv_toupper4(unsigned int x)
 {
-    return av_toupper(x & 0xFF)
-           + (av_toupper((x >> 8) & 0xFF) << 8)
-           + (av_toupper((x >> 16) & 0xFF) << 16)
-           + (av_toupper((x >> 24) & 0xFF) << 24);
+    return av_toupper(x & 0xFF) +
+          (av_toupper((x >>  8) & 0xFF) << 8)  +
+          (av_toupper((x >> 16) & 0xFF) << 16) +
+          (av_toupper((x >> 24) & 0xFF) << 24);
 }
 
 #if !HAVE_THREADS
diff --git a/libavfilter/af_channelmap.c b/libavfilter/af_channelmap.c
index 6fe8704694..44ed717688 100644
--- a/libavfilter/af_channelmap.c
+++ b/libavfilter/af_channelmap.c
@@ -149,17 +149,17 @@ static av_cold int channelmap_init(AVFilterContext *ctx, const char *args)
     } else {
         char *dash = strchr(mapping, '-');
         if (!dash) {  // short mapping
-            if (isdigit(*mapping))
+            if (av_isdigit(*mapping))
                 mode = MAP_ONE_INT;
             else
                 mode = MAP_ONE_STR;
-        } else if (isdigit(*mapping)) {
-            if (isdigit(*(dash+1)))
+        } else if (av_isdigit(*mapping)) {
+            if (av_isdigit(*(dash+1)))
                 mode = MAP_PAIR_INT_INT;
             else
                 mode = MAP_PAIR_INT_STR;
         } else {
-            if (isdigit(*(dash+1)))
+            if (av_isdigit(*(dash+1)))
                 mode = MAP_PAIR_STR_INT;
             else
                 mode = MAP_PAIR_STR_STR;
diff --git a/libavutil/avstring.c b/libavutil/avstring.c
index 45f8d78172..788667e9d6 100644
--- a/libavutil/avstring.c
+++ b/libavutil/avstring.c
@@ -285,6 +285,28 @@ int av_escape(char **dst, const char *src, const char *special_chars,
     }
 }
 
+int av_isdigit(int c)
+{
+    return c >= '0' && c <= '9';
+}
+
+int av_isgraph(int c)
+{
+    return c > 32 && c < 127;
+}
+
+int av_isspace(int c)
+{
+    return c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' ||
+           c == '\v';
+}
+
+int av_isxdigit(int c)
+{
+    c = av_tolower(c);
+    return av_isdigit(c) || (c >= 'a' && c <= 'z');
+}
+
 #ifdef TEST
 
 int main(void)
diff --git a/libavutil/avstring.h b/libavutil/avstring.h
index 5b078f15ae..438ef799eb 100644
--- a/libavutil/avstring.h
+++ b/libavutil/avstring.h
@@ -188,26 +188,17 @@ char *av_strtok(char *s, const char *delim, char **saveptr);
 /**
  * Locale-independent conversion of ASCII isdigit.
  */
-static inline int av_isdigit(int c)
-{
-    return c >= '0' && c <= '9';
-}
+int av_isdigit(int c);
 
 /**
  * Locale-independent conversion of ASCII isgraph.
  */
-static inline int av_isgraph(int c)
-{
-    return c > 32 && c < 127;
-}
+int av_isgraph(int c);
 
 /**
  * Locale-independent conversion of ASCII isspace.
  */
-static inline int av_isspace(int c)
-{
-    return c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' || c == '\v';
-}
+int av_isspace(int c);
 
 /**
  * Locale-independent conversion of ASCII characters to uppercase.
@@ -232,11 +223,7 @@ static inline int av_tolower(int c)
 /**
  * Locale-independent conversion of ASCII isxdigit.
  */
-static inline int av_isxdigit(int c)
-{
-    c = av_tolower(c);
-    return av_isdigit(c) || (c >= 'a' && c <= 'z');
-}
+int av_isxdigit(int c);
 
 /**
  * Locale-independent case-insensitive compare.
diff --git a/libavutil/version.h b/libavutil/version.h
index 4cd82268db..ee33390157 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -75,7 +75,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  52
-#define LIBAVUTIL_VERSION_MINOR  18
+#define LIBAVUTIL_VERSION_MINOR  19
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \