+/**
+ * Print a listing containing all the formats supported by the
+ * program.
+ */
+void show_formats(void);
+
+/**
+ * Print a listing containing all the codecs supported by the
+ * program.
+ */
+void show_codecs(void);
+
+/**
+ * Print a listing containing all the filters supported by the
+ * program.
+ */
+void show_filters(void);
+
+/**
+ * Print a listing containing all the bit stream filters supported by the
+ * program.
+ */
+void show_bsfs(void);
+
+/**
+ * Print a listing containing all the protocols supported by the
+ * program.
+ */
+void show_protocols(void);
+
+/**
+ * Print a listing containing all the pixel formats supported by the
+ * program.
+ */
+void show_pix_fmts(void);
+
+/**
+ * Return a positive value if a line read from standard input
+ * starts with [yY], otherwise return 0.
+ */
+int read_yesno(void);
+
+/**
+ * Read the file with name filename, and put its content in a newly
+ * allocated 0-terminated buffer.
+ *
+ * @param bufptr location where pointer to buffer is returned
+ * @param size location where size of buffer is returned
+ * @return 0 in case of success, a negative value corresponding to an
+ * AVERROR error code in case of failure.
+ */
+int read_file(const char *filename, char **bufptr, size_t *size);
+
+/**
+ * Get a file corresponding to a preset file.
+ *
+ * If is_path is non-zero, look for the file in the path preset_name.
+ * Otherwise search for a file named arg.ffpreset in the directories
+ * $FFMPEG_DATADIR (if set), $HOME/.ffmpeg, and in the datadir defined
+ * at configuration time, in that order. If no such file is found and
+ * codec_name is defined, then search for a file named
+ * codec_name-preset_name.ffpreset in the above-mentioned directories.
+ *
+ * @param filename buffer where the name of the found filename is written
+ * @param filename_size size in bytes of the filename buffer
+ * @param preset_name name of the preset to search
+ * @param is_path tell if preset_name is a filename path
+ * @param codec_name name of the codec for which to look for the
+ * preset, may be NULL
+ */
+FILE *get_preset_file(char *filename, size_t filename_size,
+ const char *preset_name, int is_path, const char *codec_name);
+
+#if CONFIG_AVFILTER
+#include "libavfilter/avfilter.h"
+
+typedef struct {
+ enum PixelFormat pix_fmt;
+} FFSinkContext;
+
+extern AVFilter ffsink;
+
+/**
+ * Extract a frame from sink.
+ *
+ * @return a negative error in case of failure, 1 if one frame has
+ * been extracted successfully.
+ */
+int get_filtered_video_frame(AVFilterContext *sink, AVFrame *frame,
+ AVFilterBufferRef **picref, AVRational *pts_tb);
+
+#endif /* CONFIG_AVFILTER */
+