WORKS:
cat output1.txt | while IFS= read -r j
do
        ffmpeg -i "${j//%20/ }" -y output.ogg
done

DOESN'T WORK:
cat output1.txt | while IFS= read -r j
do
        ffmpeg -i "${j//%20/ }" -map 0 -y -codec copy -write_id3v2 1 -metadata "track=TEST" output.mp3
done

example of line:
file:///home/xue/Music/FOLDER/The%20Folder%20Name/FILENAME.mp3