Add a way to set ffmpeg options before the -i flag.
Add a way to set ffmpeg options before the -i flag.

jhgg/discord.py,Harmon758/discord.py,khazhyk/discord.py,mgardne8/discord.py,Rapptz/discord.py,Theoretical/UselessBot,Harmon758/discord.py,imayhaveborkedit/discord.py,variablehair/Eggplantato,lgkern/PriestPy,rapptz/discord.py