Is there any way to convert a bunch of .ogg files in a folder to .mp3 using ffmpeg?
As an example, I have a bunch of .ogg files in my Downloads directory, so... to batch convert a bunch of .ogg files in a given directory to .mp3 files in the same directory, I did the following in Terminal:

cd Downloads
for f in *.ogg; do ffmpeg -i "$f" "${f%.*}.mp3"; done


This created an .mp3 file for each .ogg file I have in my Downloads directory.

So, using your directory path, do the following:

cd ~/Downloads/Minecraft+Sound+Pack+1.13/step
for f in *.ogg; do ffmpeg -i "$f" "${f%.*}.mp3"; done




That said and considering your dealing with a sound file pack you downloaded from the Internet, Minecraft+Sound+Pack+1.13.zip, which contains 131 directories, some nested 3 or more deep, and 1406 .ogg files, of which some of the filenames are the same, I would handle the situation with the following conditions in mind.


I downloaded the Minecraft+Sound+Pack+1.13.zip file from the Internet.
Expanded the zip archive by double-clicking on it in my Downloads folder in Finder. Note that this is because I do not let the Browser unzip downloaded archive files. This also retains a copy of the zip archive in case I still need it afterwards.


With that done, I used the following example bash script to convert each .ogg file within the hierarchal folder structure to an .mp3 file at the same location. Then delete the .ogg files, as I still have the original zip archive.

#!/bin/bash

    # s="/Path/To/Source/Files"

s="$HOME/Downloads/Minecraft+Sound+Pack+1.13"

for d in $(find "$s" -type f -iname '*.ogg' | sed -E 's|/[^/]+$||' | sort -u); do
    cd "$d"
    for f in *.ogg; do
        ffmpeg -i "$f" "${f%.*}.mp3"
        rm "$f"
    done
done



You only need to change the value of s="..." as or if needed and as a general rule I like to use $HOME in place of ~.


Note that this is just how I choose to deal with the situation in the moment and there are many different ways that a script could be written.  This however I believe achieves the end goal of having the hierarchal folder structure of the 131 directories intact with the 1406 converted .mp3 files.

By the way... On my old MacBook Pro, (Retina, 15-inch, Early 2013) 2.8 GHz Intel Core i7, it took just under 9 minutes to process the 1406 .ogg files.