Why would FBI not release a full frame photo or even a short video clip (with the child’s face blurred)? It seems you’d have a lot more luck identifying the woman if viewers could she what she looked like from behind. Also, would the “other person” (whose voice we hear in the background) show up in the video?
I suspect the woman saying “Stand up” is in her twenties. From the appearance of her arm and finger, my guess is she is short and overweight. From the looks of the ring, she is not well off financially.
I think she is irritated and upset with someone other than the child, and may have recently had an argument with that person. She is unhappy and has been crying, and I had to guess, she resents having to care for the child, which, from her tone, I suspect is not hers. The child could be a step child.
All jmo, complete speculation and wild guesses