@param[in,out] rate pointer to the AVRational which will contain the detected
frame rate
@paramin str the string to parse: it has to be a string in the format
rate_num / rate_den, a float number or a valid video rate abbreviation
@return >= 0 on success, a negative error code otherwise
Parse str and store the detected values in *rate.
@param[in,out] rate pointer to the AVRational which will contain the detected frame rate @paramin str the string to parse: it has to be a string in the format rate_num / rate_den, a float number or a valid video rate abbreviation @return >= 0 on success, a negative error code otherwise