debont80
5de4b40c1d
yt-dlp collapses an ffmpeg postprocessing failure to a bare "Postprocessing: Conversion failed!" with no indication of which step died, and without --verbose the underlying ffmpeg reason is never emitted at all. describeDownloadError() appends the last non-noise trailing lines (e.g. the [ModifyChapters] SponsorBlock re-encode) so the error log and completion notification point at the actual cause instead of a dead end.