GitLab

Summary:
Pull Request resolved: https://github.com/pytorch/audio/pull/3007

Simplify the construction of StreamReader/Writer in C++.

Currently these classes require client code to build AVFormatContext
manually. This is tedious and not user freindly.

Some client code actually uses the same helper function that
TorchAudio codebase uses.

This commit moves the helper logic inside of the constructor of
StreamReader/Writer, so that the signatures of these constructors
are easy to use and similar to Python interface.

Reviewed By: xiaohui-zhang

Differential Revision: D42662520

fbshipit-source-id: d95e5236810c48d7d9bd2d89c05d4f60a44b3ba1