add transcode buttons

[freeload101]

• ffmpeg check functoin
• trancode with UI dialog to set path
• add 2 trancode buttons:

• screen recording ( low quality audio ? and 1 FPS -filter:v fps=2 and high compress ?
• normal h265 transcode
  https://github.com/freeload101/SCRIPTS/blob/master/Windows_Powershell_ps/Ffmpeg_MP42H265_CUDA.ps1