[FFmpeg-user] FFMPEG concatenating a transcode as 59.88 fps instead of 60 fps

[Ryan Quinlan]

Hello all,

I am transcoding an image sequence to a 10 frame 60fps .mov files using the
first command below. I am then concatenating the exported videos using the
second command below.

*Transcode*

ffmpeg -y -r 60 -probesize 13M -start_number 1001 -i
'input_video.%04d.jpeg' -c:v libx265 -pix_fmt yuv420p10le -crf 28
-preset slower -tag:v hvc1 -vf lut3d='output_lut.cube' -r 60 -frames:v
10 -movflags faststart output_video_0001.mov

*Concatenate*

ffmpeg -y -f concat -safe 0 -i input_concat_list.txt -c copy output_concat.mov

I expected the final file from the concatenated videos to be 60fps. I am
using the -r flag twice, so it sets the input frame rate for the image
sequence and then making sure the output is 60fps as well. After the
transcode the resulting chunks are each 60fps. After the concatenation
though, when checking the frame rate in VLC, instead of the desired 60fps
VLC is showing the resulting video is 59.979960. I tried using the frame
rate flag when concatenating, but that didn't help.
Thank you for any assistance.

Ryan