Replace arrays with variable substitutions for POSIX compliance

Co-Authored-By: Rien <rien.maertens@posteo.be>

reStream.sh

@@ -78,14 +78,14 @@ fi
 
 
 
-output_args=()
-video_filters=()
+output_args=""
+video_filters=""
 
 # calculate how much bytes the window is
 window_bytes="$(($width*$height*$bytes_per_pixel))"
 
 # rotate 90 degrees if landscape=true
-$landscape && video_filters+=('transpose=1')
+$landscape && video_filters="$video_filters,transpose=1"
 
 # read the first $window_bytes of the framebuffer
 head_fb0="dd if=/dev/fb0 count=1 bs=$window_bytes 2>/dev/null"
@@ -99,17 +99,16 @@ else
     output_command=ffmpeg
 
     if [ "$format" != - ]; then
-        output_args+=('-f' "$format")
+        output_args="$output_args -f '$format' "
     fi
 
-    output_args+=("$output_path")
+    output_args="$output_args '$output_path'"
 fi
 
 # set frame presentation time to the time it was received
-video_filters+=('setpts=(RTCTIME - RTCSTART) / (TB * 1000000)')
+video_filters="$video_filters,setpts=(RTCTIME - RTCSTART) / (TB * 1000000)"
 
-joined_filters=$(IFS=,; echo "${video_filters[*]}")
-output_args+=('-vf' "$joined_filters")
+output_args="$output_args -vf '${video_filters#,}'"
 
 set -e # stop if an error occurs