Error: RequestCVPixelBufferForFrame returned: 3 for absolute frame: 47820

You just haven't found the offending clip yet. Scroll around in the general area of frame 47820, looking for black frames, white flashes, artifacts, and any other signs of corruption. It can occur in transitions and titles as well as clips. If you still have trouble, make a duplicate of your project and, working with the duplicate, cut out a sizeable chunk of footage around the area of frame 47820 in the timeline. Now see if you can export the project. If you get a successful export then you know that the corruption occurs in the footage that you deleted. If unsuccessful, then cut out a larger amount of footage until you can successfully export.

Yes, it would be great if the software could ignore a corrupted frame.

-- Rich

To find out the frame rate of a project, do the following:

Expand your timeline all the way out by using the slider located above and to the right of the timeline. Then, put your cursor on a video clip in the timeline and, while holding down the r key on your keyboard, press and drag the cursor slowly over the clip. A a yellow box will appear and expand as you drag, and a frame counter box will appear that ticks upward as you drag, showing the frames.

If it is, say, a 30fps project the counter will reach 00:29 (indicating 29 frames) and then on the next tick, when it would hit 00:30 frames, it instead will jump to 01:00, indicating one second. That shows that it is a 30fps project.

The above shows 00:29 frames, and on the next tick it will show 01:00 second. So 30 frames per second.

-- Rich

No, the iMovie timeline clock measures in ss/mm/hh.

Divide the frame rate of the project into the number of frames to get the time in seconds, and divide the seconds by 60 to get the point in time on the timeline in minutes, where the frame is located. So, if 30fps project, divide 47820 by 30 to get 1594 seconds. Divide 1594 by 60 to get 26.56 minutes as the point in the timeline where frame no. 47820 is located.

-- Rich

The frame rate of a project is set as that of the very first video clip (not photo) that is placed into a newly created project. Once the frame rate is set, it cannot be changed. You would need to create a new project and insert a video clip with the desired frame rate.

—Rich