@@ -299,13 +299,8 @@ static void mpeg1_encode_sequence_header(MpegEncContext *s)

             time_code = s->current_picture_ptr->f.coded_picture_number + s->avctx->timecode_frame_start;

             s->gop_picture_number = s->current_picture_ptr->f.coded_picture_number;

-            if (s->tc.drop) {

-                /* only works for NTSC 29.97 */

-                int d = time_code / 17982;

-                int m = time_code % 17982;

-                //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */

-                time_code += 18 * d + 2 * ((m - 2) / 1798);

-            }

+            if (s->tc.drop)

+                time_code = ff_framenum_to_drop_timecode(time_code);

             put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));

             put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));

             put_bits(&s->pb, 1, 1);

@@ -28,6 +28,15 @@

 #include "timecode.h"

 #include "libavutil/log.h"

+int ff_framenum_to_drop_timecode(int frame_num)

+{

+    /* only works for NTSC 29.97 */

+    int d = frame_num / 17982;

+    int m = frame_num % 17982;

+    //if (m < 2) m += 2; /* not needed since -2,-1 / 1798 in C returns 0 */

+    return frame_num + 18 * d + 2 * ((m - 2) / 1798);

+}

+

 int ff_init_smtpe_timecode(void *avcl, struct ff_timecode *tc)

 {

     int hh, mm, ss, ff, fps;

@@ -44,6 +44,14 @@ struct ff_timecode {

 };

 /**

+ * @brief           Adjust frame number for NTSC drop frame time code

+ * @param frame_num Actual frame number to adjust

+ * @return          Adjusted frame number

+ * @warning         Adjustment is only valid in NTSC 29.97

+ */

+int ff_framenum_to_drop_timecode(int frame_num);

+

+/**

  * Parse SMTPE 12M time representation (hh:mm:ss[:;.]ff). str and rate fields

  * from tc struct must be set.

  *