[Bug] ARM64 installer still downloads x64 ffmpeg binary

[saschanaz]

Describe the bug

ScreenToGif/ScreenToGif/Windows/Other/Downloader.xaml.cs

Lines 38 to 39 in 22a10b4

	return Environment.Is64BitProcess ? "https://www.screentogif.com/downloads/FFmpeg-4.4.1-x64.zip" :
	"https://www.screentogif.com/downloads/FFmpeg-4.3.1-x86.zip";

To Reproduce
Steps to reproduce the behavior:

1. On Surface Pro 11 (with Snapdragon X1E80100)
2. Download ScreenToGif.2.41.1.Setup.Arm64.msi from https://github.com/NickeManarin/ScreenToGif/releases/tag/2.41.1
3. Check ffmpeg download and proceed
4. Check the binary, either via:
   1. Task Manager
      1. Open Task Manager
      2. Open Details tab
      3. Make sure the "Architecture" column is visible (If not, right-click any column header and use "Select columns" context menu to check it)
      4. Save file with any ffmpeg encoding option (I used webm/rav1e)
      5. Find ffmpeg.exe in the list and check the architecture
   2. Visual Studio's dumpbin
      1. Open Visual Studio Developer Command Prompt
      2. Run dumpbin "C:\ProgramData\ScreenToGif\ffmpeg.exe" /headers
      3. Check whether FILE HEADER VALUES says ARM64 or x64

Expected behavior
ARM64 binary should be downloaded

Output

dumpbin "C:\ProgramData\ScreenToGif\ffmpeg.exe" /headers
Microsoft (R) COFF/PE Dumper Version 14.41.34123.0
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file C:\ProgramData\ScreenToGif\ffmpeg.exe

PE signature found

File Type: EXECUTABLE IMAGE

FILE HEADER VALUES
            8664 machine (x64)
               D number of sections
               0 time date stamp
               0 file pointer to symbol table
               0 number of symbols
              F0 size of optional header
             22E characteristics
                   Executable
                   Line numbers stripped
                   Symbols stripped
                   Application can handle large (>2GB) addresses
                   Debug information stripped

Desktop (please complete the following information):

• OS: Windows 11
• Version 2.41.1

Additional context
How is screentogif getting ffmpeg binary though? The code gets it from https://www.screentogif.com/downloads/, is it built from source or is it mirroring from some other distributions? If latter, then this is not immediately solvable as there's no arm64 binary distributions yet.

Related:

• Windows Arm64 binaries? BtbN/FFmpeg-Builds#375
• Windows ARM builds? GyanD/codexffmpeg#135