I use Plex to play all movies, TV shows and music videos. It plays many formats, including .mkv files. It will automatically download movie posters, subtitles, metadata, etc.
When done, you can use the "Report" (VideoSpec) and "Export" (Media Inspector) button to export a report,
attachable to your next post via the
button.
In MediaInfo you have to go to the Menu Bar, select View > Text and copy the text via CMD+A > CMD+C and paste it via CMD+V into your next post.
And if it is a torrented file, it could also be a fake.