* if f is non-NULL, returns the next registered input format after f
* or NULL if f is the last one.
*/
-AVInputFormat *av_iformat_next(AVInputFormat *f);
+AVInputFormat *av_iformat_next(const AVInputFormat *f);
/**
* If f is NULL, returns the first registered output format,
* if f is non-NULL, returns the next registered output format after f
* or NULL if f is the last one.
*/
-AVOutputFormat *av_oformat_next(AVOutputFormat *f);
+AVOutputFormat *av_oformat_next(const AVOutputFormat *f);
/**
* Allocate an AVFormatContext.
* @return 1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot.
* A negative number if this information is not available.
*/
-int avformat_query_codec(AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance);
+int avformat_query_codec(const AVOutputFormat *ofmt, enum AVCodecID codec_id,
+ int std_compliance);
/**
* @defgroup riff_fourcc RIFF FourCCs