EncoX completes conversions on iPhone, iPad and Mac, and the work happens on the device you are holding. The picture is kept when it can be kept, and re-processed only when it has to be. Whether a file plays depends on your device model and system version.
Download on the App Store
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.
EncoX 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”. EncoX chose the quietest one.
The file goes out, you wait for it to finish, then you download the result. That solves it too — 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.
EncoX 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. EncoX reads the internal codec and picture parameters before deciding anything.
When the picture codec already suits the target MP4, EncoX 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, EncoX performs a full conversion. This usually takes minutes, and longer for large files.
Audio, subtitles and metadata each follow their own rules. EncoX judges them one by one rather than applying a single blanket rule.
Inputs verified on real devices currently include MKV, MP4, AVI, TS and WebM, and generated files are MP4 only. When a source file can already be played directly, no second file is generated — that file plays as it is. 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. Blu-ray PGS subtitles, stored as laid-out images, are scanned and recognised as text and come back as a subtitle track you can resize and restyle - recognition can make mistakes, and a track that yields nothing is simply absent, with no extra warning.
With a container swap, HDR10 static metadata passes through and Dolby Vision information travels with the picture. With a full conversion, the picture is delivered at the source bit depth, up to 10-bit, with chroma at 4:2:0; what remains of Dolby Vision information after re-encoding is something we have only verified on the direct path, and we do not predict it. 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.
Converting does not require handing the file to somewhere else. For a large file, what you skip is the wait going out and the wait coming back.
One boundary is worth stating clearly: the free-allowance count syncs between your own devices through Apple’s iCloud Keychain. So the accurate claim keeps its subject narrow — the conversion step does not hand the file to somewhere else, rather than “nothing ever leaves the device”.
EncoX 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.
US$8.99
The amounts above are listed in US dollars. Apple shows and charges what you actually pay in your local currency, taxes included.
The purchase and all billing are managed by Apple. Purchases follow your Apple account, so after switching devices you can restore the purchase inside the app and it stays in effect.
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.