> ## Documentation Index > Fetch the complete documentation index at: https://magic-post.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Video processing > How MagicPost finds ffmpeg, what it uses it for, what stops working without it and how to fix the common causes. MagicPost uses `ffmpeg` and `ffprobe` to look inside videos that people upload. Publishing does not depend on them: a video without ffmpeg still goes out, but MagicPost cannot check it first. ## What ffmpeg is used for | Task | What happens without ffmpeg | | - | - | | Reading a new video's length, width and height | The length is not checked against each network's limit before publishing. A network may refuse the video later. | | Making a preview image from the frame at one second | The video has no preview in the media library or the composer. | | Setting YouTube's **Thumbnail frame** | YouTube chooses the thumbnail itself. The video still publishes. | After an upload, the media library shows one of these notes on a video it could not read: * "This server cannot read video files yet, so the length was not checked and no preview was made. It can still be published." * "This video could not be read, so its length was not checked. It may be damaged, or in a format ffmpeg cannot open." ## How MagicPost finds the programs For each of `ffmpeg` and `ffprobe`, MagicPost tries these in order and uses the first that exists: 1. The path in `FFMPEG_BINARIES` or `FFPROBE_BINARIES` in `.env`. The value only counts as a path when it contains a `/` or `\`. 2. The copy in `vendor/ffmpeg` (`ffmpeg` and `ffprobe`, or `ffmpeg.exe` and `ffprobe.exe` on Windows). If the file is there but not executable, MagicPost tries to make it executable. 3. A program with that name anywhere on the server's `PATH`. The copy in `vendor/ffmpeg` is a Linux x86-64 static build, so it runs on most shared and VPS Linux hosts without installing anything. On another system, install ffmpeg yourself and set the two keys: ```bash .env theme={null} FFMPEG_BINARIES=/usr/bin/ffmpeg FFPROBE_BINARIES=/usr/bin/ffprobe ``` Other keys that affect ffmpeg are `FFMPEG_THREADS` (default 2) and `FFMPEG_TEMPORARY_FILES_ROOT`. See [Environment variables](https://magic-post.mintlify.site/advanced/environment-variables.md). ## What the server must allow * PHP must be allowed to start programs. `proc_open` must exist and must not appear in `disable_functions` in `php.ini`. The installer lists it on the **Server Requirements** step as optional, with a warning if it is off. * The two files must be executable. After uploading with a file manager or unzipping, the executable bit is often lost. * The files must match the server's CPU. A build for a different system fails to start. * The folder must not sit on a volume mounted without permission to run programs. ## Check that it works **1. Open System health** Go to **Admin → Publishing → Settings** and read the **System health** card. Select **Check again** after any change. **2. Read the Video processing line** A working setup reads "ffmpeg", then the version number, then "from" and the path of the program. A problem shows a warning that ends with "Until then videos still publish, but their length is not checked first and they get no preview." **3. Match the reason to a fix** The text before that sentence tells you what to do. The table below lists each one. | Reason shown | What to do | | - | - | | PHP is not allowed to start other programs here (proc\_open is disabled), so ffmpeg cannot run. Ask your host to enable proc\_open. | Remove `proc_open` from `disable_functions` in `php.ini`, or ask the host to. | | `ffmpeg` (or `ffprobe`) was not found. Put it in vendor/ffmpeg, or set its path in .env as `FFMPEG_BINARIES` (or `FFPROBE_BINARIES`). | Restore the files in `vendor/ffmpeg`, or set the two `.env` keys to a working install. | | The path is not allowed to run. Make it executable with chmod +x. | Run `chmod +x vendor/ffmpeg/ffmpeg vendor/ffmpeg/ffprobe` from the application folder. | | A message from the program itself, such as "cannot execute binary file" | The build does not match the server, or the volume blocks execution. Install ffmpeg for your system and set `FFMPEG_BINARIES` and `FFPROBE_BINARIES`. | > [!NOTE] > > MagicPost runs `ffmpeg -version` once to prove the program starts, and keeps that answer for an hour. If you fix a problem that makes the program fail to start and the line does not change, wait up to an hour or clear the cache. See [Cache and optimisation](https://magic-post.mintlify.site/advanced/cache.md). ## Videos are processed in the background Image previews are made during the upload. Video analysis runs as a background job on the `media` queue, so a new video stays in processing until the scheduler or a queue worker picks it up. If videos never leave that state, the scheduler is not running. See [Scheduler and queue problems](https://magic-post.mintlify.site/troubleshooting/scheduler-and-queue.md). A single video job may run for up to 14 minutes and is tried twice. ## Related pages > [card] [File storage](https://magic-post.mintlify.site/advanced/storage.md) > > Where uploaded videos are saved and which limits apply. > [card] [Requirements](https://magic-post.mintlify.site/getting-started/requirements.md) > > PHP version, extensions and functions the server needs. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.