How about the Apollo launches ?
On Wed, Oct 19, 2016 at 12:40 AM, jimlux <[email protected]> wrote: > On 10/18/16 4:25 PM, Magnus Danielson wrote: > >> Jim, >> >> On 10/19/2016 12:51 AM, jimlux wrote: >> >>> On 10/18/16 2:30 PM, Tom Van Baak wrote: >>> >>>> Hi Vladimir, >>>> >>>> Some of these numbers survive to the present. I'm typing this post on >>>> an XP laptop where QueryPerformanceCounter() has a Frequency.QuadPart >>>> of, you guessed it, 3579545 Hz, which is why my Win32 laptop's >>>> high-res clock has ~279 ns resolution. >>>> >>>> For more fun with time, frequency, oscillators, and prime numbers, >>>> see: http://www.poynton.com/PDFs/Magic_Numbers.pdf >>>> >>>> >>> and this is why clocks in film movies on TV run slightly slow<grin>.. >>> because the film was shot at 24 fps, and it's converted to 29.97 frame >>> rate (in the US) by a 3:2 pulldown scheme. >>> >>> I am sure that all the time nuts here notice that 0.1% rate difference. >>> Over a half hour TV program it adds up to almost 2 seconds of offset. >>> (that's just because we watch things like movies shot of counters >>> running). >>> >>> Hmm.. there's probably film footage of things with a running counter in >>> the scene counting tenths or hundredths of a second (sporting events, >>> nuclear bomb tests, etc.) I wonder if you could see that difference by >>> single framing something like a filmed 100 meter race where they have an >>> onscreen timer. >>> >> >> The time-code of TV and film production runs with a frame-counter. >> Now, since the 30/1.001 factor is uneven, to get things into shape the >> factor is compensated using the drop-frame method. >> > > SO that compensates in the "big sense" so that "timecode" and "wall clock" > line up.. > > But when they do the original telecine, they're basically running a 30fps > (interpolated from 24 fps) sequence of frames at 29.97. Over the air, > there will usually be a commercial break and they can add/drop any > arbitrary number of frames to get it to line up (should they even care > about whether the on-screen clock ticking the seconds actually lines up) > > So I was thinking about something where you get a broadcast (or maybe a > video conversion on DVD/tape/online) that is a continuous piece of film. > > Seems that something like 100 meter race, which lasts 10 seconds, and will > have an on screen timer to hundredths isn't quite long enough to see the > 1.001 error (and would it be one continuous shot, or would they have edited > film together from different viewpoints). > > What about a filmed rocket launch with a countdown timer or similar? they > might have one continuous piece of film long enough. > > Partly, its going to be limited by the magazine size of the camera: a 400 > ft magazine is a bit more than 6 minutes (1 ft = 1 second in rough terms), > so that's plenty long to see the difference. > > What you really want is continuous footage lasting, say, a minute, of some > event (motivating the coverage) where there's an accurate clock visible in > the scene, where the film was originally shot at 24fps, and has been > converted to video. > > An interesting quest.... > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
