# How-to Upload Media Assets

You can upload your own media assets to OptiView storage to be played back via the OptiView CDN. These are files that are pre-transcoded before upload for distribution and are served over Dolby's CDN and can be a single asset such as an MP4 or a multi-file asset such as an HLS asset that has a series of manifests and media files.

The steps are as follows.

1. Generate Upload Credentials
2. Upload to Dolby's S3-Compatible Storage
3. Register Media Asset

## Generate Upload Credentials

Use the [Generate Upload Credentials](https://docs-preview.optiview.dolby.com/pr-863/millicast/api/media-assets-get-upload-credentials.md) endpoint to generate credentials and an S3 compatible upload location. These credentials will last for 1 hour. Please upload and register media assets within the hour.

This is an example response.

```json
{
  "status": "success",
  "data": {
    "path": "string",
    "bucketName": "string",
    "objectPrefix": "string",
    "accessKeyId": "string",
    "secretAccessKey": "string",
    "sessionToken": "string",
    "expiration": "2026-01-12T01:27:13Z"
  }
}
```

## Upload to Dolby's S3-Compatible Storage

Using the response fields *from the previous API call*, upload the media asset files to the specified S3 location.

```text
$ AWS_ACCESS_KEY_ID=<from-above> AWS_SECRET_ACCESS_KEY=<from-above> AWS_SESSION_TOKEN=<from-above> aws s3 cp <filepath> s3://<bucketName>/<objectPrefix>
```

## Register Media Asset

After completing upload make a [registration call](https://docs-preview.optiview.dolby.com/pr-863/millicast/api/media-assets-register-media-asset.md).

The `mediaAssetId` returned in the response body can be used for inspecting, retrieving and deleting the media asset.

This endpoint does not give immediate feedback on whether the media asset has been successfully created. Please use the [Read Media Asset](https://docs-preview.optiview.dolby.com/pr-863/millicast/api/media-assets-read-media-asset.md) endpoint to inspect the outcome of registration and retrieve the download url.

### Example Usage 1 - Upload A Single File Asset

If your asset has a single file such as an mp4 file, append the filename to the `objectPrefix` obtained from the [Generate Upload Credentials](https://docs-preview.optiview.dolby.com/pr-863/millicast/api/media-assets-get-upload-credentials.md) response. The [Register Media Asset](https://docs-preview.optiview.dolby.com/pr-863/millicast/api/media-assets-register-media-asset.md) request would look like

```json
{
  "objectPrefix": "<object-prefix-from-above>/user-file.mp4"
}
```

Assuming on inspection our service finds an object key that is an exact match of `objectPrefix`, OptiView will obtain and serve that single file. If there are any additional files uploaded to `s3://<bucketName>/<objectPrefix>/*` they will be ignored.

### Example Usage 2 - Upload A Multi File Asset

If your asset has multiple files such as an HLS asset with a main manifest and related manifests/media files, the [Register Media Asset](https://docs-preview.optiview.dolby.com/pr-863/millicast/api/media-assets-register-media-asset.md) request should look like this.

```json
{
  "objectPrefix": "<object-prefix-from-api-response>",
  "entrypoint": "main.m3u8"
}
```

Since the `entrypoint` is specified, the discovery url for downloading the media asset via the CDN will be a link to a copy of `main.m3u8`.

Assuming on inspection our service *does not* find an object key which exactly matches the `objectPrefix`, OptiView will obtain and serve all the contents uploaded to `s3://<bucketName>/<objectPrefix>/*`.