Blackmagic Forum

Hi,
I have seen a dozen of tutorials about counters or timelapse but didn't find what I would like to do.
Here is the situation.
I get 9000 images with a 10 seconds interval. (25 hours)
As some parts of timelapse are 'boring' (nothing much to see), timeline has speed keyframes like 100%, 800%, 1200%.
Also timeline has zoom keyframes to change a bit point of view.

I'd like to have a variable speed timer (Text+) which display time from 00h00min up to 25h00min and taking account speed keyframe. (Non linear time)

Thanks for any help.

Regards

Hey Alain
You could add your Text+ to the clip in Fusion using an expression for the text value eg 'time' will return the frame number of the composition... you'd have to use some math to present it as a time value eg with a 25 fps source 'floor(time/25)' would create a 'seconds' counter...
... but given that, with your source, every frame represents 10 seconds, and your counter also needs to represent hours and minutes then you'd have to do some coding:

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:hours=floor(time/360); minutes=floor(time/6)%60; seconds=floor(time*10)%60; return Text(string.format("%02.f",hours)..":"..string.format("%02.f",minutes)..":"..string.format("%02.f",seconds));

or the simpler

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os.date("%H:%M:%S",(time*10)-3600)

Hope it helps
Andy

Yeah, Fusion is the way to go here, IMHO. You can superimpose the time stamp on the image as Andy suggested, and then you can feed the timestamped result into a "TimeStretcher" node to speed the composited result up or slow it down where you want. For compressing (speeding up) time you can probably use "Nearest" as the interpolation mode for the TimeStretcher. Note that if you choose "Flow" as the interpolation node you'll also need to add an "OpticalFlow" node ahead of it.

Andy Mees wrote:

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:hours=floor(time/360); minutes=floor(time/6)%60; seconds=floor(time*10)%60; return Text(string.format("%02.f",hours)..":"..string.format("%02.f",minutes)..":"..string.format("%02.f",seconds));

or the simpler

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os.date("%H:%M:%S",(time*10)-3600)

Thanks Andy for this example, that's exactly what I was looking for.
I knew for formulas but I didn't know how to implement them and write the code.

In my timeLapse (9278 photos), interval setting of my camera was 10 sec but in reality pictures has been shooted with 11 sec at beginning and 13 sec at the end!!!
An average of 12 sec!!
In my time lapse I have some events that has to be dated correctly.
So doing some calculations with average interval do not match correctly. There is still some time distortion.
I have started a mathematical study using polynomial Lagrange interpolation in order use it in Expression and display correct time in final video.
I will post results when it will be finished.

Another way to do and avoid fastidious mathematical work would be to use directly in Expression Exif time data. I came across Fusion manual but didn't find such thing.

May be it's not possible to use Exif time data in Expression ?

kalain wrote:May be it's not possible to use Exif time data in Expression ?

I don't think that's currently supported Alain.
Maybe you could use something like ExifTool to extract the data and write it to an external file, then use a Frame Render script in the Fusion comp that pulls the required info for each frame? Its not something I've tried myself, but it might be worth investigating.

So, here is final results in order to display a clock text synchronised with my pictures in timelapse:

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:calcul= (9.24194*1E-13*(time^4) - 2.18266*1E-8*(time^3)+2.19407*1E-4*(time^2)+11.1452*time-11.1454 +29754);  hours=(floor(calcul/3600)%24);  minutes=(floor(calcul/60)%60); return Text(string.format("%02.f",hours).."h:".. string.format("%02.f",minutes).."m")

NB : I had to do this complex formula because interval shooting time was not constant during period of timelapse (31 hours) AND I needed to keep and display a real true (synchronised) time in video.

Thanks all for your help.