#1018 Are the labels for "time-lapse" / "slow motion" the wrong way round?

[jaimet]

I wonder whether the labels are the wrong way round in 2 places:

The help page says:

"This allows you to record video at either a faster rate (time lapse) or slower rate (slow motion)."

I think this should instead say:

"This allows you to record video at either a slower rate (for time-lapse playback) or faster rate (for slow motion playback)."

Also, in order to record time-lapse photography, I need to record at a slower rate. But when I want to do this with Open Camera, I need to select a speed that is currently displayed as 5.0x, 10.0x or 20.0x. I think that this is confusing, but I am not sure what to replace it with. Possibly:

"/5.0", "/10.0" or "/20.0" or (alternatively):
"0.2x", "0.1x" or "0.02x" or possibly just show the fps:
"6 fps", "3 fps" or "1.5 fps" (assuming those are the correct figures).

Similarly, in order to record slow motion photography, I need to record at a faster rate. But when I want to do this with Open Camera, I need to select a speed that is currently displayed as 0.5x or 0.25x.

HTH.

[Mark]

I see what you mean - I've written in from the point of view of how fast the resultant video is going, which I think is how many people will think of this. Also seems to be more in line with other camera applications, e.g. Google camera uses 5x, 10x etc for timelapse.

[jaimet]

Ok. Having recorded a time-lapse video and after analysing it using ffprobe, I can now see that I have completely misunderstood what is going on here.

I thought that changing the speed setting modified the recording frame rate.

I now understand that that is not true. Changing the speed setting modifies the video container's playback frame rate (and presumably each frame's pts).

I wanted to record at 1 fps so I set speed to "30.0x". Instead of getting a 1 fps recording, I got a 30-fps recording that mpv plays back at 900 fps.

I want to ask whether it is possible to modify the recording frame rate, but that is probably better discussed in the forums. Please feel free to close this.

Many thanks, and apologies for the noise. J