Its a huge performance issue when for every mediaUrl generation a file exist check is done here:

Not sure why it is needed but it should be avoided.

config.yml:

oneup_flysystem:
    adapters:
        storage_awss3v3:
            awss3v3:
                client: storage.s3_client
                bucket: '%s3.bucket_media%'
                prefix: media
                options:
                    ACL: 'public-read'

    filesystems:
        storage_awss3v3:
            adapter: storage_awss3v3
            alias: pb_storage_awss3v3
            plugins: [ 'pb_sulu_storage.flysystem.awss3v3.content_path.plugin' ]
        media_storage:
            adapter: storage_awss3v3
            alias: custom_alias_to_media_storage
            plugins: ['pb_sulu_storage.flysystem.awss3v3.content_path.plugin']

pb_sulu_storage:
    provider: flysystem
    flysystem:
        filesystem:
            storage: pb_storage_awss3v3
            format_cache: pb_storage_awss3v3

services.yml:

    storage.s3_client:
        class: Aws\S3\S3Client
        arguments:
            - version: 'latest'
              region: 'ca-central-1'
              credentials:
                  key: '%s3.key%'
                  secret: '%s3.secret%'
              visibility: 'public'

I'm trying to move assets (image + video) from local storage to S3 storage.
Using such an config, I have assets uploaded to S3.
Images are shown fine on frontend.

To play video, I'm trying to call URL: {{ sulu_get_media_url(media) }} - it fails with error 500 as it's trying to look for asset in local storage, not S3, although storage_awss3v3 is in config (please look at the screenshot with trace, the asset url is absolute, and it's public)

Also, image preview is not generated from video.

Could you please put words how "video" issue can be solved for sulu 1.6? Is it necessary to store files I in local folder as well or should I override MediaStreamController?
Is it possible to build yml-config to upload everything to S3 and cache to local storage after the first request?)

AwsS3v3ExternalUrlResolver, when used with a CachedAdater, return null , then in PBFormatCache->getMediaUrl , it return the relative URL instead of external URL !

This lead to continuously ask the local URL of Sulu (uploads/media) !