Question about the theory of loading a asset the Addressable System.

The default compression mode is LZ4 in Addressable Group Setting. As far as I know, a normal AssetBundle is fully loaded into RAM for the first time when a asset is read. And then the AssetBundle will compress in chunk-based form and then written back to Disk. When any asset in the this AssetBundle are loaded later, they are loaded on Chunk-Based rather than the entire AssetBundle being loaded into memory.

I don't kown if my description is wrong. If so, does the Addressable System load asset in the same way??

I don't kown where I can kown more about this theory . Can anyone help me! Thx!

 

What you describe is how bundles with LZMA compression work AFAIK. With LZMA you get a single compression stream for the entire bundle, so the result is smaller, but it is not possible to read and decompress individual files. As a result, Unity has to load and decompress the whole bundle, and then it can load specific assets on demand.
LZ4 compresses each file separately, so Unity can (in theory) load one asset from bundle on disk without having to load the entire bundle into memory. I'm not 100% sure how it works as I'm not very experienced with AssetBundles.

Just look at the source code: AssetBundleProvider and BundledAssetProvider. They use normal AssetBundle under the hood, there is no magic. Addressables is just an abstraction layer over asset bundles with a suite of useful features.

 

Thanks for you reply. @phobos2077
But I have a question. When an application loads a asset from an lz4 compressed AssetBundle package, does it load the entire AssetBundle package into memory and then unpack a corresponding asset into memory instead of unpacking all the assets?
Memory consumption is a lz4 compressed AssetBundle package plus a unpacked asset?

 

Waiting! Can anyone give me an accurate answer！！

 

wait!

 

I'd also like to know this info!

 

Assuming that this blog post can address your questions clearly: https://www.gamasutra.com/blogs/Rub...pression_Mode_for_Your_Addressable_Groups.php