Asalamulaikum I am a freelance video editor, and mostly 99% of my clients want video to have a slight background music. Video editing is my only job, and the videos I edit are halal. this is my source of income, and if I don't add bg music to it, they probably wouldn't hire me. Is it haram for me to do it?
Scholars have different opinions on music.
A summary of views permitting some kind of music is given here
There are ahadith where the Prophet (p.b.u.h) speaks negatively on playing a flute and a string instrument, and others where he did not oppose to tambourine and singing.
There's no message in the Quran opposed to music. The Quran mentions the Psalms that they have been given by God to David, and those psalms were sung with musical instruments.
However, many scholars are strictly opposing both music and films
You may decide whether you follow their interpretation and give up your profession.