Changing frame rate changes number of frames?

[KlausKi]

After having created a timeline from a number of images, I don't seem to be able to change the default frame rate of the timeline.

Whenever I change the frame rate, the number of frames is changed, too. So the playback speed doesn't actually change, but frames are getting dropped:

Animation, showing Adobe Photoshop behaviour when (a) doubling frame rate, and (b) halving frame rate.

To me, this behaviour is not reasonable. Particularly as I'm losing frames when I'm halving the timeline frame rate (see above animation, part #2).

How can I just change the frame rate to accelerate/decelerate my animation and have the timeline untouched otherwise?

[JJMack]

The number of frames should change if the video duration is the same.  Frame Rate A  times duration will not be the same as Frame Rate B times duration.  The durations should be the same the frames rate should not be the same. If the number of Frame remains the same the Duration should change.  It looks like you are seeing the duration is changing when you make the change. You are seeing  (Same number of Frames)/(different Frame rate) = (Different Duration) the video duration time is changing.

There is a big difference between a Frame Animation Timeline and a Video Timeline.  You show a video timeline the horizontal layout is Time. and a single frame rate In a frame Animation timeline the horizontal layout are frames they can have different durations set.

[JJMack]

When I change the frame rate on my widows system  I see the rate change timeline scaling change  but the duration remains the same. So try resettunf tools abd your user ID preferences,  The duration should not change the rate and numbers of frames should.

[KlausKi]

I deeply regret, sir, and I very much regret writing this ... but I didn't understand a word from what you have written.

You sure put very much endeavour in your answer, but ... probably, due to my lack of knowledge of the English language ... I only read a number of half sentences and a sequence of equally looking images - plus an animation at the end.

Would you mind elaborating on this issue again?

From what I got from your answer, you are true: I would expect the "frame rate" to be equal to the rate a frame is getting replaced by the next frame. I wouldn't expect the rate to have influence on the number of frames. From my perspective these are two distinct parameters.

[JJMack]

Some how the second Post I posted dropped and series of screen captures I included in the post the shoed when I changed the frame rate in a video timeline.  The default 30FPS  for a 4 second video Change to 15 FPS after I click OK the next screen capture showed 15 FPS.  I the changed it to a custom 5 FPS.  After I click OK the next screen capture showed 5 FPS.  In all Screen capture the video duration remained  a constant 4seconds.  The time scale size change not the time.  I spread it out so it size would display  about the same size on screen.   That is why I suggested resetting Tools and user ID Preferences.   You animated gif seem to show you video duration was being changes.   That should only happen when you drag on the end of the clip to change its duration which would not change the  frame rate.

[KlausKi]

That's strange .. I'm using a fresh installation of PhotoShop CC 2018. No settings changed yet. I'm using the program's default settings.

I'd expect the playback speed to increase (= time lapse) when raising the frame rate, and to see the playback slow down (= slow motion) when I lower the frame rate.

[JJMack]

KlausKi  wrote

I'd expect the playback speed to increase (= time lapse) when raising the frame rate, and to see the playback slow down (= slow motion) when I lower the frame rate.

If the number of frames was a constant that would be the case the duration would change.  However if Photoshop keeps the duration the same Photoshop would render more or less frames the video frame rate.

If you have an hour movie and to want cut down the amount of data over the network  you  lower the frame rate like to 15FPS. If you sent all the flames your hour 30FPS video has the movie would take 2hours to play and you did not cut done on the amount of data transmitted you just did it slower.  What the video encoder dose is generate half the numbers of frame  you have for your 30FBS Video for the 15FPS video.  The movie is played at a rate of 15FPS. It play in an hour.

My rotating red rectangle is a smart object layer.  It has no frames  But on at time I created a key frame at 0 Second at second 1 I created a key frames where I have rotated the rectangle 90 degrees at time 2 second an other key frame  and an additional  90 degree rotation at t 3 seconds the same  and again at the time 4second an other 90 degrees  360 degrees in total.    I created 4 frames.  Photoshop generates the frames between the four I created for the frame rate I set.   The rate will effect the number of frames generated by Photoshop.  O low rate a ruff jumpy rotation rectangle,  a high rate a smooth rotating rectangle.