+void ff_read_frame_flush(AVFormatContext *s);
+
+#define NTP_OFFSET 2208988800ULL
+#define NTP_OFFSET_US (NTP_OFFSET * 1000000ULL)
+
+/** Get the current time since NTP epoch in microseconds. */
+uint64_t ff_ntp_time(void);
+
+/**
+ * Probe a bytestream to determine the input format. Each time a probe returns
+ * with a score that is too low, the probe buffer size is increased and another
+ * attempt is made. When the maximum probe size is reached, the input format
+ * with the highest score is returned.
+ *
+ * @param pb the bytestream to probe, it may be closed and opened again
+ * @param fmt the input format is put here
+ * @param filename the filename of the stream
+ * @param logctx the log context
+ * @param offset the offset within the bytestream to probe from
+ * @param max_probe_size the maximum probe buffer size (zero for default)
+ * @return 0 in case of success, a negative value corresponding to an
+ * AVERROR code otherwise
+ */
+int ff_probe_input_buffer(ByteIOContext **pb, AVInputFormat **fmt,
+ const char *filename, void *logctx,
+ unsigned int offset, unsigned int max_probe_size);
+
+#if LIBAVFORMAT_VERSION_MAJOR < 53
+/**
+ * @deprecated use av_url_split() instead
+ */
+void ff_url_split(char *proto, int proto_size,
+ char *authorization, int authorization_size,
+ char *hostname, int hostname_size,
+ int *port_ptr,
+ char *path, int path_size,
+ const char *url);
+#endif
+
+/**
+ * Assemble a URL string from components. This is the reverse operation
+ * of av_url_split.
+ *
+ * Note, this requires networking to be initialized, so the caller must
+ * ensure ff_network_init has been called.
+ *
+ * @see av_url_split
+ *
+ * @param str the buffer to fill with the url
+ * @param size the size of the str buffer
+ * @param proto the protocol identifier, if null, the separator
+ * after the identifier is left out, too
+ * @param authorization an optional authorization string, may be null.
+ * An empty string is treated the same as a null string.
+ * @param hostname the host name string
+ * @param port the port number, left out from the string if negative
+ * @param fmt a generic format string for everything to add after the
+ * host/port, may be null
+ * @return the number of characters written to the destination buffer
+ */
+int ff_url_join(char *str, int size, const char *proto,
+ const char *authorization, const char *hostname,
+ int port, const char *fmt, ...);
+
+/**
+ * Append the media-specific SDP fragment for the media stream c
+ * to the buffer buff.
+ *
+ * Note, the buffer needs to be initialized, since it is appended to
+ * existing content.
+ *
+ * @param buff the buffer to append the SDP fragment to
+ * @param size the size of the buff buffer
+ * @param c the AVCodecContext of the media to describe
+ * @param dest_addr the destination address of the media stream, may be NULL
+ * @param port the destination port of the media stream, 0 if unknown
+ * @param ttl the time to live of the stream, 0 if not multicast
+ */
+void ff_sdp_write_media(char *buff, int size, AVCodecContext *c,
+ const char *dest_addr, int port, int ttl);
+
+/**
+ * Write a packet to another muxer than the one the user originally
+ * intended. Useful when chaining muxers, where one muxer internally
+ * writes a received packet to another muxer.
+ *
+ * @param dst the muxer to write the packet to
+ * @param dst_stream the stream index within dst to write the packet to
+ * @param pkt the packet to be written
+ * @param src the muxer the packet originally was intended for
+ * @return the value av_write_frame returned
+ */
+int ff_write_chained(AVFormatContext *dst, int dst_stream, AVPacket *pkt,
+ AVFormatContext *src);
+
+/**
+ * Get the length in bytes which is needed to store val as v.
+ */
+int ff_get_v_length(uint64_t val);
+
+/**
+ * Put val using a variable number of bytes.
+ */
+void ff_put_v(ByteIOContext *bc, uint64_t val);
+
+/**
+ * Read a whole line of text from ByteIOContext. Stop reading after reaching
+ * either a \n, a \0 or EOF. The returned string is always \0 terminated,
+ * and may be truncated if the buffer is too small.
+ *
+ * @param s the read-only ByteIOContext
+ * @param buf buffer to store the read line
+ * @param maxlen size of the buffer
+ * @return the length of the string written in the buffer, not including the
+ * final \0
+ */
+int ff_get_line(ByteIOContext *s, char *buf, int maxlen);
+
+#define SPACE_CHARS " \t\r\n"
+