doxygen: Include libavcodec and libavformat examples into the documentation

Doxyfile

@@ -591,7 +591,7 @@ EXCLUDE_SYMBOLS        =
 # directories that contain example code fragments that are included (see
 # the \include command).
 
-EXAMPLE_PATH           =
+EXAMPLE_PATH           = libavcodec/api-example.c libavformat/output-example.c
 
 # If the value of the EXAMPLE_PATH tag contains directories, you can use the
 # EXAMPLE_PATTERNS tag to specify one or more wildcard pattern (like *.cpp

libavcodec/api-example.c

@@ -20,8 +20,9 @@
 
 /**
  * @file
- * avcodec API use example.
+ * libavcodec API use example.
  *
+ * @example libavcodec/api-example.c
  * Note that this library only handles codecs (mpeg, mpeg4, etc...),
  * not file formats (avi, vob, etc...). See library 'libavformat' for the
  * format handling

libavformat/output-example.c

 /*
- * Libavformat API example: Output a media file in any supported
- * libavformat format. The default codecs are used.
- *
  * Copyright (c) 2003 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -22,6 +19,16 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
+
+/**
+ * @file
+ * libavformat API example.
+ *
+ * @example libavformat/output-example.c
+ * Output a media file in any supported libavformat format.
+ * The default codecs are used.
+ */
+
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>