Improve grammar: "X next after Y" -> "next X after Y".

Originally committed as revision 17347 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -2661,7 +2661,7 @@ int avpicture_deinterlace(AVPicture *dst, const AVPicture *src,
 
 /**
  * If c is NULL, returns the first registered codec,
- * if c is non-NULL, returns the registered codec next after c,
+ * if c is non-NULL, returns the next registered codec after c,
  * or NULL if c is the last one.
  */
 AVCodec *av_codec_next(AVCodec *c);

libavformat/avformat.h

@@ -689,14 +689,14 @@ extern AVOutputFormat *first_oformat;
 
 /**
  * If f is NULL, returns the first registered input format,
- * if f is non-NULL, returns the registered input format next after f,
+ * 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);
 
 /**
  * If f is NULL, returns the first registered output format,
- * if f is non-NULL, returns the registered output format next after f,
+ * 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);

libavformat/avio.h

@@ -145,7 +145,7 @@ extern URLInterruptCB *url_interrupt_cb;
 
 /**
  * If protocol is NULL, returns the first registered protocol,
- * if protocol is non-NULL, returns the registered protocol next after protocol,
+ * if protocol is non-NULL, returns the next registered protocol after protocol,
  * or NULL if protocol is the last one.
  */
 URLProtocol *av_protocol_next(URLProtocol *p);