[Makefile] Movie Workflow

Makefile

all:
	rm -f _output.mp4
	for mp4 in *.mp4; do echo file $$mp4; done > list.txt
	ffmpeg -f concat -i list.txt -c copy _output.mp4

ifdef NO
NEXT_NO := $(shell echo $$(printf "%02d" $$((10#$(NO) + 1))))
endif

last:
	@if [ -z "$(NO)" ]; then \
		echo "Error: NO variable is required."; \
		exit 1; \
	fi
	ffmpeg -i $(NO)-*.mp4 -update 1 -q:v 1 $(NEXT_NO).png

tempo:
	@if [ -z "$(TEMPO)" ] || [ -z "$(INPUT)" ] || [ -z "$(OUTPUT)" ]; then \
		echo "Error: TEMPO, INPUT, and OUTPUT variables are required."; \
		exit 1; \
	fi
	ffmpeg -i $(INPUT) -vf "setpts=PTS/$(TEMPO)" -af "atempo=$(TEMPO)" $(OUTPUT)

cut:
	@if [ -z "$(DUR)" ] || [ -z "$(INPUT)" ] || [ -z "$(OUTPUT)" ]; then \
		echo "Error: DUR, INPUT, and OUTPUT variables are required."; \
		exit 1; \
	fi
	ffmpeg -i $(INPUT) -t $(DUR) -c copy $(OUTPUT)