Convert !UT to MP4

A video downloaded through µTorrent may retain a .!ut suffix while the download is incomplete, preventing normal playback, editing, or sharing. To use the video in a phone, TV, editor, or upload service that expects MP4, first complete the torrent and then convert the finished source file if necessary.

What !UT files are

.!ut is not a video format. µTorrent Classic can append this suffix to unfinished torrent files when Options → Preferences → General → Append .!ut to incomplete files is enabled. For example, movie.mkv.!ut is normally a partially downloaded MKV file, not a distinct !UT media file.

An incomplete file can lack video frames, audio data, or the index needed for playback. Renaming movie.mkv.!ut directly to movie.mp4 does not convert it and can disrupt µTorrent's tracking of an active download.

What MP4 files are

MP4 is a multimedia container used by phones, TVs, browsers, sharing services, and editing applications. For the widest device support, use H.264 video and AAC audio in an MP4 container. MP4 can also contain H.265/HEVC, but older devices and some web services may not support it.

Some completed videos can be placed in an MP4 container without re-encoding, which preserves their original quality. This works only when the video and audio streams are accepted by MP4 and by the intended playback device.

Complete the torrent before conversion

1. Open the torrent in µTorrent and let it reach 100%. Confirm the relevant file is complete in the torrent's Files tab.
2. If the torrent stopped or files were moved, use µTorrent's Force Re-Check command. Missing pieces cannot be recreated by a converter or video-repair tool; the torrent needs available seeders to finish.
3. After completion, µTorrent normally removes the suffix automatically. The result might be movie.mkv, movie.avi, movie.mov, or already be movie.mp4.
4. If µTorrent verifies the file as complete but the suffix remains, close or stop the torrent first and make a backup. Remove only .!ut: rename movie.avi.!ut to movie.avi, not to movie.mp4.

Convert the completed video to MP4

FFmpeg provides the most control. If the completed source already uses MP4-compatible streams, such as H.264 video and AAC audio, remux it without quality loss:

ffmpeg -i "movie.mkv" -map 0:v -map 0:a? -c copy -movflags +faststart "movie.mp4"

-movflags +faststart moves MP4 indexing data to the beginning of the file, which helps web playback. Stream copying can fail or create poorly compatible output when the source has unsupported audio, subtitles, or video codecs.

For broad playback compatibility, re-encode the completed file to H.264 and AAC:

ffmpeg -i "movie.mkv" -c:v libx264 -crf 20 -preset medium -c:a aac -b:a 192k -movflags +faststart "movie.mp4"

Lower -crf values produce higher-quality, larger H.264 files; 18 to 23 is a practical range. Re-encoding takes longer and introduces generational quality loss.

For a desktop interface, open the completed source in HandBrake. Under Summary, set Format to MP4; under Video, select H.264 (x264); under Audio, select AAC; then use Start Encode. HandBrake cannot repair missing torrent data.

CloudConvert is a suitable online option for a completed, correctly named video when uploading it is acceptable. Do not upload raw .!ut files, and avoid online conversion for large, confidential, or copyrighted files you are not authorized to share.

Compatibility limits

A file that opens before the torrent finishes is still not necessarily complete; early file headers and downloaded segments may be enough for partial playback. Finish and hash-check the torrent before converting or archiving it.

Lossless remuxing preserves video quality but does not make unsupported codecs compatible. DTS audio, image-based subtitles, attachments, and some legacy codecs may be omitted, rejected, or unsupported by an MP4 player; re-encode audio or use a different container when those streams must be retained.