Is it possible to remove a border from a Webm video losslessly? I know that Matroska does have a way to remove the border by editing its metadata, and i also know that Webm is a cheaper version of Matroska. I have tried using MKVtools to edit Webm and it appears to work, but then when i play the file nothing changes.
So does Webm support metadata removal of border from the video? If it does what tool can i use to perform this task?
See here https://www.webmproject.org/docs/container/ under section Track. There you find PixelCropBottom, PixelCropTop, PixelCropLeft and PixelCropRight - all of which are supported. These parameters should do what you want. They also exist for Matroska.
Look for a tool that can manipulate those parameters.