for f in *.ogg; do
    name="${f%.ogg}"
    ffmpeg -f lavfi -i color=c=black:s=1920x1080 -i "$f" \
        -c:v libx264 -tune stillimage \
        -c:a aac -b:a 192k \
        -pix_fmt yuv420p \
        -shortest \
        "${name}.mp4"
done