# Extract or insert audio artwork
Robot: `/audio/artwork`
🤖/audio/artwork extracts embedded cover artwork from audio files or inserts a new cover image into them. Extracted artwork can be piped into other Steps such as /image/resize. Use `method: "insert"` to embed artwork into audio files like MP3, FLAC, or M4A.
This Robot extracts or inserts cover artwork in audio files.
For extraction, it uses the image format embedded within the audio file — most often, this is JPEG. If you need the image in a different format, pipe the result into [🤖/image/resize](/docs/robots/image-resize.md).
For insertion, provide both an audio file (as `"audio"`) and an image file (as `"image"`) via the `use` parameter, and set `method` to `"insert"`. The image will be embedded as the cover artwork of the audio file.
Stage: ga
## Usage example
Extract embedded cover artwork from uploaded audio files:
```json
{
"steps": {
"artwork_extracted": {
"ffmpeg_stack": "v7",
"robot": "/audio/artwork",
"use": ":original"
}
}
}
```
## Parameters
### `interpolate`
Controls whether Assembly Variables are interpolated for individual instruction fields.
By default, most Robot instruction fields interpolate Assembly Variables. Set this to `false` to treat every instruction field as literal text, or set an individual field path to `false` to treat only that field as literal text. For Robot-specific fields that are literal by default, set this to `true` or set that field path to `true` to opt back into interpolation.
Use field names such as `path`, or dotted paths such as `ffmpeg.vf` for nested objects.
Type: `boolean | Record`
### `output_meta`
Allows you to specify a set of metadata that is more expensive on CPU power to calculate, and thus is disabled by default to keep your Assemblies processing fast.
For images, you can add `"has_transparency": true` in this object to extract if the image contains transparent parts and `"dominant_colors": true` to extract an array of hexadecimal color codes from the image.
For images, you can also add `"blurhash": true` to extract a [BlurHash](https://blurha.sh) string — a compact representation of a placeholder for the image, useful for showing a blurred preview while the full image loads.
For images, `"thumbhash": true` instead extracts a base64-encoded [ThumbHash](https://evanw.github.io/thumbhash/) into `meta.thumbhash`, together with `meta.has_alpha` (whether an alpha channel exists, even when fully opaque). It describes EXIF-oriented pixels and uses the first frame of animated images. Extraction is best-effort: images above 40 megapixels, unsupported formats, or a failed/bounded decode produce no placeholder. Successful extraction adds a metadata charge equivalent to 20% of that file's bytes. No ThumbHash surcharge applies when disabled or when no hash is produced.
Set this option on the Step producing the image, such as `/upload/handle` for uploaded originals or `/image/resize` for processed outputs. Setting it only on `/transloadit/store` does not request extraction: storage preserves the producer's metadata. Transloadit Storage persists a generated hash with its immutable version and returns it in stored results and native asset reads. Direct S3 uploads do not generate placeholders. A placeholder contains image information, so protect it with the same access controls as the full image.
For videos, you can add the `"colorspace": true` parameter to extract the colorspace of the output video.
For videos, you can also add `"interlaced": true` to detect whether the video is interlaced. This combines the cheap ffprobe `field_order` flag with a bounded `idet` sampling pass over the first frames of the source, exposing `interlaced`, `field_order`, and a diagnostic `interlace_detection` object under `file.meta`. This is computationally expensive and billed accordingly.
For audio, you can add `"mean_volume": true` to get a single value representing the mean average volume of the audio file.
You can also set this to `false` to skip metadata extraction and speed up transcoding.
Type: `Record | boolean | Array`
### `user_meta`
Adds custom JSON metadata to each emitted file without changing its contents. Nested objects and arrays are supported.
Inheritance depends on the Robot. Values merge with existing `user_meta` on the output file; the current Step replaces matching top-level keys. Assign required keys explicitly when a Robot creates fresh outputs.
In processing Steps, `${file.*}` refers to the first input and `${result.*}` to the emitted file. Values are evaluated per output after the Robot runs, before subsequent metadata extraction and temporary storage. On `:original`, values are evaluated per upload before metadata extraction.
Downstream Steps read `${file.user_meta.key}`. See [Custom metadata](https://transloadit.com/docs/topics/assembly-variables.md#user-meta) for a complete example and inheritance rules.
Type: `Record`
Default: `{}`
### `result`
Whether the results of this Step should be present in the Assembly Status JSON
Type: `boolean`
Default: `false`
### `queue`
Setting the queue to 'batch', manually downgrades the priority of jobs for this step to avoid consuming Priority job slots for jobs that don't need zero queue waiting times
Type: `batch`
### `force_accept`
Force a Robot to accept a file type it would have ignored.
By default, Robots ignore files they are not familiar with.
[🤖/video/encode](/docs/robots/video-encode.md), for
example, will happily ignore input images.
With the `force_accept` parameter set to `true`, you can force Robots to accept all files thrown at them.
This will typically lead to errors and should only be used for debugging or combatting edge cases.
Type: `boolean`
Default: `false`
### `ignore_errors`
Ignore errors during specific phases of processing.
Setting this to `["meta"]` will cause the Robot to ignore errors during metadata extraction.
Setting this to `["execute"]` will cause the Robot to ignore errors during the main execution phase.
Setting this to `true` is equivalent to `["meta", "execute"]` and will ignore errors in both phases.
Type: `boolean | Array`
Default: `[]`
### `use`
Specifies which Step(s) to use as input.
* You can pick any names for Steps except `":original"` (reserved for user uploads handled by Transloadit)
* You can provide several Steps as input with arrays:
```json
{
"use": [
":original",
"encoded",
"resized"
]
}
```
* You can also tag input Steps with `as` to pass semantic intent to robots:
```json
{
"use": [
{
"name": ":original",
"as": "image"
},
{
"name": ":original",
"as": "mask"
}
]
}
```
> [!Tip]
> That's likely all you need to know about `use`, but you can view [Advanced use cases](/docs/topics/use-parameter.md).
Type: `string | Array | Array