[cuno]

Hi, author here.

Funny you should give the stream-encoding MP4 example, because yes that is what people's experience has been for S3. We've solved that - no temporary local file needed - all streamed directly to S3, for example using ordinary ffmpeg. The trick is a deeper understanding of how multi-part upload works, and if necessary, server-side copy semantics on those parts.

[ilyt]

So how does it work if say application would edit some metadata in existing file on existing object ?

[cuno]

Depends on what you mean by metadata. MP4 metadata is data inside the file - and is modified by server-side-copy semantics that replaces only the bits that are changed. If you mean POSIX metadata, we avoid storing that in the object, and for performance store that elsewhere (it's encoded and compressed in the actual filename of hidden files).