title: ffmpeg - Specifying timecode for a video in drop frame rate
body: <p>I want to create a copy of an existing video.mxf and give it a new starting timecode. This timecode is drop frame rate, and at 59.94fps (the same as in video.mxf). I know that this means that the first four frames (00, 01, 02, 03) are skipped in drop frame rate, at the start of every minute that is not a multiple of 10. I run</p>
  
  <pre><code>ffmpeg -i video.MXF  -metadata timecode=00:08:00;04 -codec copy video_newTC.MXF  
  </code></pre>
  
  <p>While ffmpeg executes this, there is a "timecode" entry that says "00:08:00;04". I then run:</p>
  
  <pre><code>ffprobe video_newTC.MXF
  </code></pre>
  
  <p>and the "timecode" entry says "00:08:00;20". </p>
  
  <p>It seems that for every full minute in the specified timecode, ffmpeg adds an additional 2 frames to whatever I specify (I could understand 4 frames, since 00->03 are skipped...). If the timecode that ffmpeg calculates passes the full-minute mark, an additional 2 frames are added. E.g. specifying the timecode as "00:07:59;59" results in ffmpeg giving video_newTC a starting timecode of "00:08:00;17" (59 + 16 + 2). Can anyone shed some light on what ffmpeg is doing?</p>