Complete documentation for av_set_string().

Originally committed as revision 14436 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/opt.h

@@ -99,10 +99,30 @@ typedef struct AVOption {
  */
 const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
 
+/**
+ * @see av_set_string2()
+ */
 attribute_deprecated const AVOption *av_set_string(void *obj, const char *name, const char *val);
 
 /**
  * Sets the field of obj with the given name to value.
+ *
+ * @param[in] obj A struct whose first element is a pointer to an
+ * AVClass.
+ * @param[in] name the name of the field to set
+ * @param[in] val The value to set. If the field is not of a string
+ * type, then the given string is parsed.
+ * SI postfixes and some named scalars are supported.
+ * If the field is of a numeric type, it has to be a numeric or named
+ * scalar. Behavior with more than one scalar and +- infix operators
+ * is undefined.
+ * If the field is of a flags type, it has to be a sequence of numeric
+ * scalars or named flags separated by '+' or '-'. Prefixing a flag
+ * with '+' causes it to be set without affecting the other flags;
+ * similarly, '-' unsets a flag.
+ * @return a pointer to the AVOption corresponding to the field set or
+ * NULL if no matching AVOption exists, or if the value \p val is not
+ * valid
  * @param alloc when 1 then the old value will be av_freed() and the
  *                     new av_strduped()
  *              when 0 then no av_free() nor av_strdup() will be used