Loading PHAsset data FAST.

问题

I am using requestimageforasset to load assets, just as described in the Apple Dev Documentation.

It works and all, but I find it very very VERY slow when it comes to very large assets, such as videos of several hundreds of megabytes.

My goal is to load an asset, copy a chunk of its data, and send that chunk to a server.

I load chunks because of obvious reasons, RAM limitation.

I have a couple of questions in mind about this:

1. How can I copy chunks of large video assets really fast?

2. Can I get any direct and fast access to asset data without calling requestimageforasset?

3. Should I maintain the requestimageforasset open until I send the data and then leave it's completion block?

So, what approach should I take and where can I find info about this?

来源：https://stackoverflow.com/questions/32918479/loading-phasset-data-fast