This is ambiguous. It could mean:
Yes. Use HandBrake (free, open-source) to re-encode h264 to h265 (HEVC) or to reduce file size. This is converting, not installing.
Let us dissect the user query into its core segments.
If you see a file named Teacher’s_Pet_2025_Setup.exe, Install_First.exe, or Codec_Installer.msi—delete it immediately. Run a full antivirus scan.