Author Topic: Is there a chronometer option?  (Read 465 times)

unelune

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Is there a chronometer option?
« on: May 01, 2018, 05:47:15 AM »
Hi,

In regards to a magnet experiment that I'm doing, I need to have an onscreen chronometer that starts at 0 second (obviously) at the "Mark in" frame.

If that's not possible, does some know how to have a chronometer appear on the MP4 video?

I need this to measure how many rotation per second a repulsed magnet rotates (at very high speed) within a distance of 10 cm.

Any help or comments would be appreciated.

regards,
jonathan

John DeLonghi

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Re: Is there a chronometer option?
« Reply #1 on: May 01, 2018, 08:55:27 AM »
Usually this is something done in editing, but I don't know how much experience you have of that side of things. You will also need to know the frame rate you shot with in order to make the onscreen clock accurate.

I can see how it would be quite useful to have a function built into the camera which burns the frame number into the video as an option, but I suspect it's not high on the list of things to do, so if  I were you I'd learn how to do it in post.

NiNeff

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Re: Is there a chronometer option?
« Reply #2 on: May 02, 2018, 06:10:33 PM »
Here's a quick and dirty way to do it in post using ffmpeg stolen from another thread:
Yeah, the first thing I do with the files is use FFMPEG to slow the play rate from 60fps to 30fps, and also to add a time marker to each frame.  For example, here's the command to do that on a 640x120 clip (17424 being the fps):
Code: [Select]
ffmpeg -i ChronosFile1.mp4 -r 30
 -vf "setpts=(2/1)*PTS,
 drawtext=fontfile=Arial.ttf: expansion=normal:
   text='%{eif\:n*1000/17424\:d}.%{eif\:mod(n*1000/17424*100,100)\:d\:2}ms':
   x=(w-tw-5): y=5: fontcolor=white: box=1: boxcolor=0x00000099: fontsize=25"
 -an -y ChronosFile1Post.mp4

unelune

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Re: Is there a chronometer option?
« Reply #3 on: May 04, 2018, 08:17:55 AM »
Thanks to you both,

Unfortunately, I have no experience in editing, so I would not know how to do this in a software. But I will still try to figure it out.

As for the FFMPEG option, it does look like Chinese at first hand but let's see if I can translate that -lol- this weekend.

Perhaps I could ask Krontech for a feature request as this Chronometer option would be very helpful for all those buying this camera for research purposes like myself.

regards,
jonathan