+uint32_t avpriv_framenum_to_smpte_timecode(unsigned frame, int fps, int drop);
+
+/**
+ * @brief Load timecode string in buf
+ * @param buf Destination buffer
+ * @param tc Timecode struct pointer
+ * @param frame Frame id (timecode frame is computed with tc->start+frame)
+ * @return a pointer to the buf parameter
+ * @note timecode representation can be a negative timecode and have
+ * more than 24 hours.
+ * @note buf must have enough space to store the timecode representation: 16
+ * bytes is the minimum required size.
+ */
+char *avpriv_timecode_to_string(char *buf, const struct ff_timecode *tc, unsigned frame);
+
+/**
+ * Check if timecode rate is valid and consistent with the drop flag.
+ *
+ * @return 0 on success, negative value on failure
+ */
+int avpriv_check_timecode_rate(void *avcl, AVRational rate, int drop);