When a 4K HDR source meets an HD SDR target, the wider color range has to map into the narrower one. There are at least half a dozen ways to do that. Get it wrong and the highlights clip or the shadows mud. Picked for you.
Frame rate cadence is the same kind of trap. 23.976, 24, 29.97, drop-frame timecode — the math when source and target don’t match is unforgiving. Picked for you.
Chroma subsampling matched to use: 4:2:0 for the web, 4:2:2 when graphics work downstream needs the precision. Picked for you.
Audio left alone when you’re just copying channels, normalized to the right LUFS target when you’re re-encoding for streaming or broadcast. Picked for you.
Color space, frame rate cadence, audio loudness — every tricky decision a video tool throws at you. Picked for you.
Override any of them. You almost never need to.
One source. One job. One finished file.