7 Replies Latest reply on Jun 10, 2009 5:43 PM by Jim_Simon

    TIMECODE - indept

    Frédéric Leclair Level 1

      I currently been confronted to lacunes to my knownledge, which I though was adequate, of Timcodes.

       

      Was is the difference between:

      29.97 drop

      29.97 non-drop

      30 drop

      30 non-drop

      59.94 drop

      59.94 non-drop ?

       

      I always though that 29.97 and 59.94 where what we called 30 drop-frame and that 30 non-drop was pure 30 fps...

      Sound editing software seems to think differently on this. I don't even have that option when I create a new sequence in Premiere...

       

      When I create a 60i sequence it's written that it's 59.94, hence: 29.97...

      and for 30ish TC I can choose 30 NDF or 29.97...

       

      Can someone clarify the distinctions here or direct me to a site that does so ?

       

      Thank you.

        • 1. Re: TIMECODE - indept
          Harm Millaard Level 7

          Am I lucky to be in PAL country! I have better resolution (576 versus 480), I have better colors (no IRE restrictions) and no confusion about frame rates, just 25. Life would have been so much simpler it the Yanks had simply admitted that PAL was the better standard, instead of their obstinate adherence to NEVER THE SAME COLOUR.

          • 2. Re: TIMECODE - indept
            Frédéric Leclair Level 1

            Tell that to the guy which setup electricity to 60 instead of 50 like in Europe...

            • 3. Re: TIMECODE - indept
              Jim_Simon Level 8

              There is a difference between "frame rate" and "timecode".

               

              30i is the correct shortcut for normal NTSC video.  This is sometimes mislabled as 60i, but the two are the same thing.  The first is correctly listing frames per second, the second is incorrectly listing fields per second.

               

              29.97 is a slightly more accurate appelation for normal video frame rates.  Like 60i, this one often get's mislabled as 59.94.  (The first is frame rate, the second is field rate.)

               

              Timecode is a wholly separate issue, and can be either Drop Frame (the standard) or Non-Drop Frame.  Because the frame rate isn't exactly 30 frames per second (hence the 29.97), if you were to label every frame sequentially, the 'duration' in timecode would not match the duration in real time.  So a system was worked out whereby certain timecode numbers are 'dropped' from the sequence, thus keeping the timecode fairly accurate relative to real time.

              • 4. Re: TIMECODE - indept
                Frédéric Leclair Level 1

                Thanks Jim, I'm aware of this, but even if TC and frame rate are 2 different thing, they are related.

                 

                If I export a 29.97 (60i) project for sound and I get all these choices, which should I take?

                 

                If they put choices, there must be a reason ?! Some are same thing put different way like 59.94 and 29.97, but what about other ?

                 

                When I edit I got 30 NDF TC, but my footage is 29.97.

                If I export this in a sound software, what would be right choice?

                Seems to me that many options are same thing put another way, but they'll change TC and clips position and ultimate lenght of project...

                • 5. Re: TIMECODE - indept
                  Frédéric Leclair Level 1

                  Here answer from a tech friend, it's in French but those in need will take time to figure it out...

                   

                   

                  "Drop vs NON-drop, c'est vraiment juste dans la façon de compter les frames par rapport au temps réel en NTSC.Dans l'industrie, tout le monde utilise du drop, parce que si t'as 3000 frames, en non-drop ça fait 100 secondes alors qu'en drop ça fait 100 secondes et 3 frames. Donc drop donne le vrai temps en NTSC et là où il y a du 29.97, 23.98, 59.94. Quand le 0.03 rattrape le temps, le drop va skipper le numéro du frame  ( genre de 12  à 14 au lieu de 12 à 13, mais tu perds pas de frame, c'est juste le nbuméro). J'ai regardé vite vite sur internet pour le 30DF vs 30NDF et on dit que le 30DF c'est absurde, mais peut-être que c'est l'inverse dans le sens de si en 30DF l'audio sera bon exacte sur du 2997NDF et 30NDF sur du 2997DF, je sais pas... ( http://chambinator.free.fr/french/time2fr.htm ) ça a rapport avec le moment de la capture je crois, comment on a créé le timecode (http://www.2-popforums.com/forums/archive/index.php/t-69136.html). Je crois qu'on recommende du son 30NDF sur une séquence NTSC..

                  sinon, 23.98, c'est 24fps, 29.97 c'est 30fps, 59.94i c'est du 30frames forcément entrelacés, field dominance du moins même si c'est progressif, mais 59.94p serait du 60fps, encore là DF ou NDF, c'est juste la façon de compter le timecode pour garder le temps réel.
                  "

                  • 6. Re: TIMECODE - indept
                    Jim_Simon Level 8

                    If they put choices, there must be a reason ?!

                     

                    I see what you're saying.

                     

                    29.97 are video frame rates.  The "30" choices are probably for film.  The 59.94 choices are likely HD options only, which can run at 60 progressive fps.

                    • 7. Re: TIMECODE - indept
                      Jim_Simon Level 8

                      When I edit I got 30 NDF TC, but my footage is 29.97.

                       

                      Got where?

                       

                      If I export this in a sound software, what would be right choice?

                       

                      Sound don't care either way.  It looks for things like bit depth and sampling rate.