CineX converts on iPhone, iPad and Mac. The video file itself does not need to be uploaded, and the picture is only re-processed when it has to be.
Conversion finished
When a video refuses to open, the cause is often not the file itself, but the fact that what it carries sits outside what the current playback method can handle. What helps is not switching to another player — it is making the file itself into something the system recognises.
CineX does one thing: it reads the codec actually used inside the file, then chooses how to turn it into MP4. When the picture can be left untouched, it only swaps the container; only when it must be re-processed does it perform a full conversion.
That is why two similar files can take very different amounts of time — not instability, but the result of judging correctly.
There are many ways to solve “it won’t open”. CineX chose the quietest one.
Send the file to a remote server, wait for it to finish, then download the result. It works — but you have to hand the file over first.
The file stays on your iPhone, iPad or Mac. Conversion happens here, and the result lands here too.
CineX does not go by the extension. It reads the codec actually used inside the file, then decides which path to take.
The same .mkv carrying H.264 and one carrying Xvid are two different situations. CineX reads the internal codec and picture parameters before deciding anything.
When the picture codec already suits the target MP4, CineX only adjusts the packaging — the picture data is not re-compressed. This is usually a matter of seconds.
When the picture codec falls outside what the system can handle directly, CineX performs a full conversion. This usually takes minutes, and longer for large files.
Audio, subtitles and metadata each follow their own rules. CineX judges them one by one rather than applying a single blanket rule.
Inputs verified on real devices currently include MKV, MP4, AVI and TS. The output is MP4 only — there is no format menu, because there is only one format that fits the goal.
Tracks that can be kept are kept; those that cannot are converted to AAC. Multiple tracks are never merged into one, and channel counts and sample rates are left as they were.
Text subtitles such as SRT and ASS are carried into the MP4; ASS positioning and colour are reduced to plain text. Image-based subtitles such as PGS, VobSub and DVD subtitles are not preserved.
With a container swap, HDR10 static metadata passes through and Dolby Vision metadata is preserved. With a full conversion, Dolby Vision metadata is not preserved and 10-bit or HDR picture is converted to 8-bit. This limit is stated plainly because it is worth knowing before you convert.
The free version includes 5 successful conversions in total: failed, cancelled and retried jobs do not count, and deleting an output does not restore one. Opus is a one-time purchase that unlocks one thing only — unlimited conversion count. Picture quality and speed are the same as the free version.
The video file does not need to be uploaded in order to be converted. For large files, what you skip is the upload wait and the download wait.
One boundary is worth stating clearly: the free-allowance count syncs between your own devices through Apple’s iCloud Keychain. So the accurate way to put it is narrower — the video file does not need to be uploaded, rather than “nothing ever leaves the device”.
CineX is designed around the way iPhone, iPad and Mac are used. It is not a replacement player and it does not ask you to change how you watch — it only makes the file into something the system recognises.
Better to read them here than to discover them after converting.
Opus membership unlocks one thing only: unlimited conversion count. No monthly fee, no auto-renewal, and no quality or speed tiers.
US$8.99 in the U.S. store and ¥38 in China. The purchase follows your Apple ID, so after switching devices you can restore it through the App Store.
Format detection, path judgement, track handling — all of it happens behind the scenes. What you should feel at the end is simply: open it, and watch.