Paul wrote:
Chop (to uncompressed intermediate format):

ffmpeg -i KEY01.mp4 -map 0 -copytb 1 -c:v rawvideo -pix_fmt bgr24 -af "volume=6dB"
-ac 2 -c:a pcm_s16le -f segment -segment_list out.list
-segment_frames 26267,52535,78803,105071,131339,157607,183875,2101 43,236411,262679,288947
G:\WORK\out%03d.mov

Then, twelve encoding instances similar to this:

cd /d C:\FFMPEG\bin
ffmpeg -i G:\WORK\out000.mov -vcodec cinepak -ac 2 -acodec pcm_s16le G:\WORK\a00.mov

The join operation is almost purely a file copy operation,
with only the ends being spliced in a lossless way.
The rate operator corrects the damaged frame rate.

ffmpeg -f concat -r 30000/1001 -i filelist.txt -c copy N:\concattest2.avi

The filelist.txt has twelve lines similar to this:

file 'G:\WORK\a00.avi'

Noted, thanks.