[FFmpeg-user] How can I get byte-accurate segments?

[Grant Curtis]

I'm working with a Speech-to-text service that wants audio files that are
exactly 160kb large, which means 80,000 16-bit samples

So far I've converted my video stream into an audio file with a sampling
rate of 16,000 and converted it to s16le. Now I just have to grab 80,000
samples out of it.

Is there any way to do that? Or perhaps I need to begin with a source file
in a specific bitrate so that the math lines up?