ffmpeg command to encode videos for Sylvania SDVD9020B portable DVD players

#!/bin/bash

# This command line works well enough to encode videos for my Sylvania SDVD9020B
# portable DVD players. There are still mysterious issues with aspect ratio, but
# this method is the best compromise I've found so far in about two hours of
# digging and experimentation.

# Observations:
# setting an aspect ratio of 16:9 seems to work for 2.35:1
# video. Not sure why.

ffmpeg -i "$1.mkv" -c:v mpeg4 -qscale:v 5 -vf setsar=1,scale=480:-1:,setdar=16:9 -c:a libmp3lame -b:a 128k ~/"$1 [portableDVD].mp4"