Display between reading head and timeline keyframe

[Stormadv]

Hi everyone, I wanted to report a problem that sometimes occurs, in a project

(the one in the attached image is at 25 fps)

there are display anomalies between the reading head and the timeline keyframe, in practice the reading head does not coincide with the frame or keyframe (look at the attached image), it's a bug or is there a method to fix this problem?

Thank you for reply.

[JohnColombo · Accepted solution]

Hi @Stormadv,

The highlighted area around your CTI is an indicator of the current Shutter Angle and Shutter Speed settings for Motion Blur in the composition. Based on your screenshot, you have a Shutter Angle of 360º (which will make the highlight the full duration of a frame) and the Shutter Phase is -90º, which pulls the highlight earlier in time by 1/4 of the frame (this is the offset you are seeing).

Let me know if that lines up with your settings. If you want the highlight to align with the CTI, set your Shutter Phase to 0º, keeping in mind that this will change the look of your motion blur.

Cheers,

- John, After Effects Engineering Team 

[Stormadv]

I did a test and verified what you wrote, I confirm that the reason is that, I learned something else from AE,

thanks for the contribution. SOLVED!

[Rick Gerard · Accepted solution]

When you zoom into the timeline far enough, you can view the shutter angle of the virtual comp camera. Your screenshot shows a shutter angle of about 270º and zero offset. This will exaggerate the motion blur on layers.  

A shutter angle of 180º and an offset of -90º will closely match the motion blur of a traditional motion picture camera. The frame rate doesn't change the display in the timeline. The highlighted area has nothing to do with timing. It is not a bug. 

If you change the frame rate of a composition from 60 fps to 24 fps, the keyframe positions may not line up with the start of a frame after the rate change. This is also not a bug because keyframes are set based on time, not frame number. If a keyframe is set at 0:00:03:33 in a 60 fps comp, the time of the keyframe will be 3.33 seconds. If you change the frame rate to 24 fps, the keyframe will still be at 3.33 seconds, but it will show up just to the right of the start of frame 0:00:03.13. That is also not a bug, and it won't foul up the timing of the animation because it will still move at the nearest frame.

[Stormadv]

I did a test and verified what you wrote, I confirm that the reason is that, I learned something else from AE,

thanks for the contribution. SOLVED!