Same-codec re-muxes (e.g. WMV → FLV where both can hold H.264) produce nearly-identical sizes. Codec changes can swing it dramatically: H.264 → VP9/AV1 typically cuts the file 30-50% at the same visual quality; H.264 → H.265 roughly halves it; VP9 → H.264 grows it.
Same-codec re-mux: under a minute (no re-encode pass). Re-encode to a different codec: typically 0.3-0.7× source duration on our pipeline, so a 1-hour WMV → FLV finishes in 18-40 minutes. AV1 is the slowest target; VP9 and H.265 are mid-range; H.264 is fastest.
Not in the same step — use /trim-video/ or /resize-video/ to clip and crop the WMV first, then queue the WMV → FLV step. Doing them in series is faster than re-encoding the whole file just to shave seconds off the ends.