-/**
- * 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.
- * @param[out] o_out if non-NULL put here a pointer to the AVOption
- * found
- * @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
- * @return 0 if the value has been set, or an AVERROR code in case of
- * error:
- * AVERROR(ENOENT) if no matching option exists
- * AVERROR(ERANGE) if the value is out of range
- * AVERROR(EINVAL) if the value is not valid
- */
-int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
-
-const AVOption *av_set_double(void *obj, const char *name, double n);
-const AVOption *av_set_q(void *obj, const char *name, AVRational n);
-const AVOption *av_set_int(void *obj, const char *name, int64_t n);
-double av_get_double(void *obj, const char *name, const AVOption **o_out);
-AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
-int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);
-const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
-const AVOption *av_next_option(void *obj, const AVOption *last);
-int av_opt_show(void *obj, void *av_log_obj);
-void av_opt_set_defaults(void *s);
-void av_opt_set_defaults2(void *s, int mask, int flags);
-