Questions and answers.

Ounce makes video files smaller without making them look noticeably worse. You drop in a video, a folder, folders inside folders, or an entire drive, choose a format, a quality and a maximum resolution, and it works through everything it finds.

Both. You choose the format going out separately from whatever came in, so Ounce works as a converter as well as a compressor. Give it a folder of MOV files and ask for MP4 and that is what you get back. It reads 19 container types including MP4, M4V, MOV, AVI, MPG, MPEG, MKV, M2TS, MTS, TS, 3GP, WMV, FLV, WebM, OGV, MXF, ASF, DIVX and VOB, and writes MP4 with HEVC or H.264, or WebM with AV1 or VP9.

Yes. That is what Ounce is built for. Drop in a folder, folders nested inside folders, or an external drive full of video, and it searches through everything inside and finds the videos for you. You do not need to open each folder or select files one at a time.

Whichever you prefer. By default Ounce writes the compressed copy beside the original and leaves the original untouched. If you switch on Replace Originals, it will replace them, but only after checking that the new file is complete, playable and genuinely smaller, and the original then goes to your Mac Trash where you can recover it rather than being deleted outright.

Nothing is done twice. Ounce marks each file it has completed with the exact settings it used, so on a second run it recognises those files and skips them. You can drag the same folder or the same drive in again next month and it will pick up only what is new or changed.

No. Real folders are messy, and Ounce is designed for that. You can give it a folder holding huge originals, videos you compressed before, files Ounce has already processed, duplicate folders and files that are already about as efficient as they will get. It checks what it finds and avoids unnecessary work.

No. Ounce deliberately steps around application packages, including Photos, Final Cut, iMovie, Logic and Premiere libraries, and does not rewrite their internal files. It looks for ordinary video files it can safely process instead.

Ounce never overwrites a file it did not create. If the name it wants is taken, it writes a different filename and leaves the existing file where it is.

The default setting is aimed at a difference you would struggle to see. Compression is lossy, so something is always given up in principle, but the goal is to take away file size you do not need before quality you can actually notice. There are stronger settings if you want a smaller result and are willing to see the trade.

No. It checks before starting by encoding short sample sections at your chosen settings to estimate whether there is anything to gain, and it checks again after finishing. If the finished file is not actually smaller than the original, it is discarded and your original is kept.

Never. The resolution setting is a maximum, not a target. Choose 4K and give Ounce a 1080p video and it stays 1080p. Upscaling would make the file larger without adding real detail. The cap applies to the shorter side, so portrait video keeps its proportions.

Ounce opens the finished file again and reads through it to confirm it is complete and playable, rather than assuming a conversion that reached 100 per cent worked. Only then is the file accepted, and only then will it replace an original if you asked it to.

The conversion in progress stops, not just the queue, and any incomplete output is discarded. You are not left with half a video sitting beside the original looking like a finished file.

Usually yes, and often a great deal. In one test a folder of fourteen iPhone videos that were already HEVC came back 211 MB smaller in under five minutes on an M1 Pro, with several files ending up close to half their original size.

Because your phone has to compress while it is recording. It gets one pass, in real time, with no idea what is coming next in the shot, and it cannot fall behind or overheat. So it holds a steady, generous data rate throughout, and a plain wall is given the same budget as a busy street. Ounce works on the finished file with no camera waiting on it, so it can spend data where the picture needs it and very little where it does not.

Ounce requires an Apple silicon Mac and macOS 14 or later. Intel Macs are not supported, and the App Store listing states that plainly.

For MP4 using HEVC or H.264, Ounce uses the dedicated media engine built into Apple silicon, which on an M1 Pro runs at roughly eight times real time while using only a small share of the CPU, so the Mac stays usable. WebM using AV1 or VP9 is slower because no current Apple chip has a hardware encoder for those, so that work is done on the CPU.

MP4 with HEVC is the all round choice and the fastest, and suits shrinking an archive you want to keep. MP4 with H.264 is the one to pick when a file must open anywhere. WebM with AV1 gives the smallest files and suits video going onto a website. WebM with VP9 is the web option where older browsers still matter.

Ounce is 9.99 US dollars, paid once. There is no subscription, no account, no in-app purchase and no paid tier holding back features. Future updates to the app are included.

No. All the encoding happens on your Mac. Ounce does not request network permission from macOS at all, so it is not able to send anything anywhere, which you can verify yourself by inspecting the app entitlements. There is no account, no analytics, no telemetry and no advertising.

Yes, completely. Because nothing is uploaded there is no file size limit, no queue behind anyone else, and no internet connection required. It works on a plane.

For MP4 output, Ounce keeps the source metadata rather than stripping it. For WebM output using AV1 or VP9, source metadata such as GPS location is deliberately not carried into the finished file, because WebM is mainly a web delivery format where publishing the location a video was recorded is rarely wanted.