An audio commentary is an additional audio track, usually digital, consisting of a lecture or comments by one or more speakers, that plays in real time with a video. Commentaries can be serious or entertaining in nature, and can add information which otherwise would not be disclosed to audience members.[1]
In accounting terms, operating expenses, or OE, and cost of goods sold, or COGS, are both considered expense accounts. In short, they measure different ways in which resources are spent in the process of running a business.
Cost of goods sold is an expense charged against sales to work out a gross profit (see definition below). So, for example, we may have sold 100 units this year at $4 each, and these 100 units that we sold cost us $3 each originally.