NXTV Audiogram generator

Makefile

INPUTS       := $(wildcard ./audio/*.mp3)
OUTPUTS      := $(patsubst ./audio/%.mp3,./output/%.mp4,$(INPUTS))
BACKGROUNDS  := $(patsubst ./audio/%.mp3,./backgrounds/%.png,$(INPUTS))

AFILTERS := agate
VISUALISATION := showwaves=s=1920x1000:colors=\#ececec:mode=cline
POSTPROC := geq=r='r(X,Y)':a='0.75*alpha(X,Y)'
OVERLAY := overlay=0:300

VFILTER := ${AFILTERS},${VISUALISATION},${POSTPROC}

all: $(OUTPUTS)

./backgrounds/%.png : ./audio/%.mp3
    cat bkg.svg | sed 's/\#title\#/$(shell basename -s .mp3 $<  | sed 's/[[:lower:]]/\U&/g' | sed 's/\_/\ /'  )/' > temp.svg
    inkscape --export-png=$@ --export-area-page -w 1920 -h 1080 temp.svg

./output/%.mp4 : ./backgrounds/%.png ./audio/%.mp3
    @echo $(word 2, $^)
    ffmpeg -y \
        -i $(word 2, $^) \
        -loop 1 -i $(word 1, $^) \
        -filter_complex "[0:a]${VFILTER}[v];[1:v][v]${OVERLAY}[outv]" \
        -map "[outv]" \
        -map 0:a \
        -c:v libx264 -b:v 5M \
        -c:a libfdk_aac -ar 48k \
        -shortest $@