ffmpeg video generation process optimization
Here's the combined command,

ffmpeg \
-i 1.jpg \
-i 2.jpg \
-i 3.jpg \
-i 4.jpg \
-i 'audio.mp3' \
-i 'logo.png' \
-filter_complex \
"[0:v]zoompan=z='if(lte(zoom,1.0),1.5,max(1.001,zoom-0.0015))':d=125,fade=t=out:st=4:d=1[v0]; \
 [1:v]zoompan=z='if(lte(zoom,1.0),1.5,max(1.001,zoom-0.0015))':d=125,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1[v1]; \
 [2:v]zoompan=z='if(lte(zoom,1.0),1.5,max(1.001,zoom-0.0015))':d=125,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1[v2]; \
 [3:v]zoompan=z='if(lte(zoom,1.0),1.5,max(1.001,zoom-0.0015))':d=125,fade=t=in:st=0:d=1,fade=t=out:st=4:d=1[v3]; \
 [v0][v1][v2][v3]concat=n=4:v=1:a=0,format=yuv420p,scale=800:450,setsar=1[v]; \
 [v][5]overlay=25:25,drawbox=y=ih-80:color=#ef2626@0.8:width=iw:height=80:t=fill,drawtext=text='This is a testing text example.':expansion=normal:y=h-line_h-20:x='if(eq(t\,0)\,w\,if(lt(x\,(0-tw))\,w\,x-4))':fontfile='Lora/Lora-Regular.ttf':fontcolor=white: fontsize=40" \
-c:a copy -shortest ./out_fade.mp4