Is the Compression Progress Bar Accurate?

How progress is actually reported

Transcoding runs in a background processing thread, which periodically reports "processed up to this second of the video." The tool divides that by the total duration to get a ratio between 0 and 1, shown as a percentage on the progress bar.

Does progress stalling at one number mean something is wrong?

If progress doesn't move for several to a dozen seconds, it usually just means the current segment is computationally demanding (fast motion, complex texture) — normal variation. It's only worth considering a page refresh and retry if progress stays completely unchanged for several minutes or more and the browser tab is fully unresponsive.

Next to the percentage the card also shows an estimated time remaining. It is extrapolated from the average speed since progress began, and is hidden for the first few seconds and the first 3% so the number doesn't jump around; it adjusts as scene complexity changes, so treat it as a guide. If you'd rather not wait, both running and queued tasks have a Cancel button. The first time compatibility mode is used, the card first shows the engine download progress, which is separate from compression progress.