MSFT: 47710450 - Add support for building FFmpeg/FFmpegInterop binaries without VCLibs framework package dependencies

[brbeec]

Why is this change being made?

We're adding support for building FFmpeg/FFmpegInterop binaries without VCLibs framework package dependencies (e.g. msvcp140_app.dll, vcruntime140_1_app.dll, vcruntime140_app.dll).

Additional reading:

• Introducing the Universal CRT - C++ Team Blog (microsoft.com)
• Upgrade your code to the Universal CRT | Microsoft Learn

What changed?

• Added --platform-type switch to BuildFFmpeg.bat that gets plumbed down to vcvarsall.bat to set up the build environment. FFmpeg binaries can be built without VCLibs framework package dependencies by not specifying --platform-type store or --platform-type uwp.
• Updated FFmpegInterop project to support building without VCLibs framework package dependencies by setting the UseUCRT property.
• Replaced usage of codecvt, which was deprecated in C++17, with C++/WinRT APIs.
• Fixed x86 build break due to C4018: signed/unsigned mismatch warning in FLACSampleProvider::FLACSampleProvider() which became an error after MSFT: 49309119 - Reduce FFmpegInterop's storage footprint by brbeec · Pull Request #307 · microsoft/FFmpegInterop (github.com) set TreatWarningAsError=true.

How was the change tested?

I validated the following scenarios for build configurations with and without VCLibs framework package dependencies:

• Ogg playback in MediaPlayerCPP
• Ogg playback in Media Player with WME (in-proc and out-of-proc)
• Ogg properties in File Explorer with WME (in-proc and out-of-proc)

I validated the removal of VCLibs framework package dependencies in all of the FFmpeg/FFmpegInterop binaries using depends.exe.