timecode: support >24h timecode.

libavcodec/timecode.c

@@ -94,7 +94,7 @@ char *avpriv_timecode_to_string(char *buf, const struct ff_timecode *tc, unsigne
     ff = frame_num % fps;
     ss = frame_num / fps        % 60;
     mm = frame_num / (fps*60)   % 60;
-    hh = frame_num / (fps*3600) % 24;
+    hh = frame_num / (fps*3600);
     snprintf(buf, 16, "%s%02d:%02d:%02d%c%02d",
              neg ? "-" : "",
              hh, mm, ss, tc->drop ? ';' : ':', ff);

libavcodec/timecode.h

@@ -67,7 +67,8 @@ uint32_t avpriv_framenum_to_smpte_timecode(unsigned frame, int fps, int drop);
  * @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
+ * @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.
  */