Compose small videos from video registrator into big single video (with front and back camera tracks)

Makefile

.PHONY: clean rename video

ffmpeg := /mnt/c/Users/roman/Downloads/ffmpeg-4.4-full_build/ffmpeg-4.4-full_build/bin/ffmpeg.exe
filename = $(shell ls Front/${mask}* | head -n 1 | cut -d. -f1 | xargs -n 1 basename)

front.txt:
	ls Front/${mask}* | sed "s/.*/file '&'/" > front.txt

back.txt:
	ls Back/${mask}* | sed "s/.*/file '&'/" > back.txt

video: front.txt back.txt
	${ffmpeg} \
			-loglevel error -stats \
			-f concat -safe 0 -i front.txt \
			-f concat -safe 0 -i back.txt \
			-filter_complex "[1]scale=iw/3:ih/3 [pip]; [0][pip] overlay=main_w-overlay_w-10:main_h-overlay_h-10" \
			-c:a copy \
			-c:v h264_nvenc -profile:v high -bf 2 -g 30 -crf 18 -b:v 20M  -pix_fmt yuv420p -s 1920x1080 \
			-movflags faststart \
			Composed/${filename}.mp4

fix:
	${ffmpeg} \
			-i Composed/NO20210710-163901-002215F.mkv \
			-ss 00:05:00 \
			-filter_complex "[0:v:1]scale=iw/3:ih/3 [pip]; [0:v:0][pip] overlay=main_w-overlay_w-10:main_h-overlay_h-10" \
			-c:a copy \
			-c:v h264_nvenc -profile:v high -bf 2 -g 30 -crf 18 -b:v 20M  -pix_fmt yuv420p -s 1920x1080 \
			-movflags faststart \
			Composed/NO20210710-163901-002215PIP.mp4

clean:
	rm -f front.txt back.txt

all: video clean