---
title: "compress · RUAL Documentation"
description: "Compresses a video file with ffmpeg as a background queue job. Use a preset for standard message-media output, or override individual settings. Wire on_…"
canonical: https://docs.rual.nl/block-types/video/video_compress
language: en
---

# compress

This block is part of the [`video`](https://docs.rual.nl/block-types/video) group and was last modified in core [`v15.0.0`](https://docs.rual.nl/core-versions/150000).

Compresses a video file with ffmpeg as a background queue job. Use a preset for standard message-media output, or override individual settings. Wire on_complete_function / on_error_function to react to the result.

- flow `flow`

- file required `value` Input video file. Accepts a file object (from another file block) or a relative path string.

- preset required `value` One of: mssgs_media (1280px, 2.5Mbps), mssgs_media_premium (1920px, 4Mbps), custom.

Default `mssgs_media`

- output file `value` Optional output path. When empty, a hash-named .mp4 is generated alongside the input.

- max size `number` Override longest-side cap. Set to 0 to disable scaling.

- video bitrate `value` Override target video bitrate, e.g. "2500k".

- max rate `value` Override VBV ceiling, e.g. "3000k".

- buf size `value` Override VBV buffer, e.g. "6000k".

- audio bitrate `value` Override audio bitrate, e.g. "128k".

- fps `number` Override target frames per second.

- passthrough `value` Arbitrary data forwarded verbatim to the callback function's passthrough inpin.

- wait in flow `condition` When true, the block blocks until the compression job finishes and populates the result outpins synchronously. Default false : the flow continues immediately and the callback function handles the result.

- wait timeout (s) `number` How long to wait when wait_in_flow=true before giving up with WAIT_TIMEOUT.

Default `300`

- flow `flow`

- queue guid `value` GUID of the enqueued compression job. Feed this to function_wait_for_queue_item or use for cancellation.

- output file `value` Path where the compressed file will be written when the job runs.

- width `number` Output width in pixels : populated only when wait_in_flow=true.

- height `number` Output height in pixels : populated only when wait_in_flow=true.

- duration ms `number` Output duration in milliseconds : populated only when wait_in_flow=true.

- size bytes `number` Output file size in bytes : populated only when wait_in_flow=true.

- success `condition` Whether compression succeeded : populated only when wait_in_flow=true.

- error `value` Set when enqueueing fails synchronously, when wait_in_flow times out, or when the ffmpeg job fails (only with wait_in_flow=true). When wait_in_flow=false, ffmpeg errors flow to on_error_function.

- on complete `execute_function` Function invoked when compression succeeds. Fires regardless of wait_in_flow.

- on error `execute_function` Function invoked when compression fails. Fires regardless of wait_in_flow.

| `video compress` |
| --- |
| `ffmpeg` |
| `transcode` |

A [function trigger](https://docs.rual.nl/block-types/globals/trigger_custom_function) starts the flow and [compress](https://docs.rual.nl/block-types/video/video_compress) transcodes the file from the file pin using the preset pin. Both pins take plain values here, from [value](https://docs.rual.nl/block-types/value/value_default) blocks. Compression runs in the background; the queue guid, dimensions and success pins report back when done.

![Studio canvas example for the compress block: compressing an uploaded video.](https://docs.rual.nl/canvas-examples/video_compress.png)

### Version history

Introduced in [`v15.0.0`](https://docs.rual.nl/core-versions/150000).