5 Replies Latest reply: Feb 13, 2012 10:24 AM by prescovidprod RSS

    Video Basics: Clearification on Nomenclature/Specs

    prescovidprod Community Member

      We are starting to use video more and more where I work, and I am trying to get a much better understanding of how what the nomenclature actually means with regard to video, especially as it relates to SLRs. We may consider buying a N800, and I want to be clear what I can do with it.

       

      However, I have some basic questions that I am sure you pros can answer:

       

      Why is it that if you shoot something at 60i, the frame rate is still 29.97?

       

      Or does 60i or 24p have nothing to do with frame rate?

       

      How do I deturmine what is the best frame rate choice?

       

      Also, do you think it is worth pulling down the native 24p footage we shoot in our prosumer camera, using inverse telecine, because it is primarily for online, or will it be a marginal improvement?

       

      How can i tell if the SLR i am looking at shoots slow motion, or time lapse?

       

      Are most of the examples on youtube that I am seeing, do their speed changes in post with a plugin like twixtor? Is it best to shoot at the highest framerate you can if you plan on doing something like this?

       

      Is timelapse usually a long series of stills of short video clips?

       

      Thx in advance.

        • 1. Re: Video Basics: Clearification on Nomenclature/Specs
          Community Member

          hmmmm

           

          my suggestion is to check out books at your local library and also use google or another search engine to get some of the fundamental info you are looking for... mainly cause you will also get illustrations and graphics that help to " show " you what the text is explaining.

           

          it's not that what you're asking is too hard to answer concisely here... but would take a bit of time and explanation and lead to other questions etc... so that I really think some books and lots of searching on internet would really help you a lot.

           

          For example, if I said to you that some digital video is sometimes related to older FILM cameras regarding terms and adaption... so that it may be assumed at 180 degree film shutter ( that spins near the film gate ) lets light expose the film 1/2 the time, so that 24 FPS means the effective shutter speed is really 1/48th / sec... and that shutter speed determines in part how much the frame gets blurred from "action" .. it may need some illustrations and graphics to really understand what is happening.  That shutter speed ( and frame rate combined ) may or may not freeze action to the point where you're happy with slow motion or fast motion playback..

           

          Where 60i ( i = interlaced ) is different than progressive ( 24p p=progressive ) is also best explained with illustration ( for me at least it was very important to see it illustrated )...

           

          You're best off with some basic books with those illustrations etc in my opinion.. and would be faster way for you to learn and use as references for later questions , etc.

           

          good luck

          • 2. Re: Video Basics: Clearification on Nomenclature/Specs
            JSS1138 CommunityMVP

            The convention for long form specs is to list the horizontal resolution, an i or p indicating interlaced or progressive, a slash, and then the frame rate. Like this:

             

            480i/30 - This is normal NTSC video.

            480p/24 - This is 'film like' NTSC video.

            1080i/30 - One of the ATSC (high definition) standards.

            720p/60 - Another ATSC standard.

             

            The shorthand convention is to drop the resolution and slash, and move the i or p after the frame rate.  Like this:

             

            30i

            24p

            30i

            60p

             

            Camera makers started confusing the issue by changing the frame rate to field rate, so that the proper notation of 30i got incorrectly listed as 60i.  This has caused much confusion.

            • 3. Re: Video Basics: Clearification on Nomenclature/Specs
              JSS1138 CommunityMVP

              Your frame rate choice will be decided by answering one question.  Do you want the video look, or the film look?  For the former, you'd use a 30i* or 60p setting.  For the latter, you'd use a 24p setting.

               

              This applies to any resolution.

               

               

              *Take note that most cameras incorrectly list 30i as 60i.  Technically they do mean two different things, but from a camera settings viewpoint, they mean the same thing.

              • 4. Re: Video Basics: Clearification on Nomenclature/Specs
                prescovidprod Community Member

                Thanks all for the speedy reply.

                 

                Yes, able123, I am reading everything. It still can be confusing. I understand where 24fps comes from and interlaced and progressive and all that. I just dont understand that when I shoot 60i, and bring it into premeire regardless of the sequence setting (24p or 60i) it still comes in at 29.97.

                 

                Now, granted, I am using a cannon vixia hfs10 for now, which wraps the 24p in a 60i package (AVCHD/.mts files), but just not getting why it wont be slower?

                 

                I have tried various sequence settings when i open the file, and various export settings when I finish. Still the same result.

                 

                That is why i asked about extracting the native 24p from the 60i wrapper the vid camera puts it in.

                 

                Jim, thanks also, that explains the nomenclature really well. Ya think the industry could use the same terms? @@&^#@*!!!!

                • 5. Re: Video Basics: Clearification on Nomenclature/Specs
                  prescovidprod Community Member

                  Correction...Canon Vixia HFS11...(ooooo...big difference....LOL)