How to decode a big video use ffmpeg.wasm to render use canvas?

When using ffmpeg in c language for decoding, the decoder will read a few frames and decode them according to the decoding timestamp. Therefore, it will not load a lot of frame data at one time, and the memory usage is very small. But wasm cannot access local files, so it must be used Buffer transfers video resources to wasm. What if the video file is very large? What is the maximum memory that ffmpeg.wasm supports to transfer?

I see this in README
What is the maximum size of input file?
2 GB, which is a hard limit in WebAssembly. Might become 4 GB in the future.

2GB refers to the compressed data of the video, like h264 data size? which needs to be read into the memory all at once through js, and then sent to wasm?