.smi
Subtitles · application/smil+xml
Opens with
Captions laid over video. They are text files pairing timestamps with lines, so you can edit them yourself.
| MIME type | application/smil+xml |
|---|---|
| Category | Subtitles |
| Opens in a browser | No |
| Plain text | Yes |
| Registered type | Yes |
How to read this
- An extension is a label, not the contents. Rename a file to .png and if the bytes inside are JPEG, it is still a JPEG.
- A MIME type is how the internet names a file kind. Browsers look at that value, not the extension, to decide whether to display or download.
- A MIME type starting with x- was never registered as a standard. Plenty are in wide use, but they are not official names.
- Video extensions name a container. The same .mp4 may play on one device and not another, depending on the codec inside.
Frequently asked questions
Q. What is a .smi file?
It belongs to the subtitles category and its MIME type is application/smil+xml. The contents are plain text, so you can even open it in Notepad and read it.
Q. What opens a .smi file?
PotPlayer, VLC, Notepad all handle it. In a browser it does not display — the browser downloads it instead.
Q. What is the MIME type of .smi?
application/smil+xml. The first half, application, names the broad kind; the second half, smil+xml, names the exact format. It is a registered standard name.
Q. Can I convert a .smi file to another format?
Yes — open it and re-save through a converter. Renaming alone changes only the label; the bytes stay put, and programs that check the real format may refuse to open it.
Q. My .smi file will not open.
First check that PotPlayer is installed. If it still fails, the download may have been cut short, or the file may only be named .smi while holding a different format inside.