Amazon S3 upload and viewing code for video/audio/photo sharing site.

We are using a social video/audio/photo sharing software called Rayzz, written in PHP. It currently uploads and displays videos, audio, and photos from the local server on which it is installed. We want to modify any upload, display and embed coding to utilize our Amazon S3 account. Amazon suggest using the Multipart Upload API for large files and this is what we want to use. We are not sure if the High-level or Low-level API should be used so we need a recommendation/suggestion as to which would be best. ** Amazon Multipart info page: [login to view URL] Upload and viewing coding must be able to upload and view large files 5GB+ without dropping connection. We also need a one time copy of all video, audio, and photo files uploaded to our S3 bucket. Here are current viewing page examples: Video View Page [login to view URL] Audio Listen Page [login to view URL] Photo View Page [login to view URL]