Matroska container format auto-rotation during playback via a tag or metadata, supported by MPC-HC, MPCBE, PotPlayer

The MP4 container format (*.mp4) has a particular tag or metadata to tell players to auto-rotate a video during playback, surprisingly, the Matroska container format (*.mkv) has its own counterpart for at least three players to do the same, namely: MPC-HC, MPC-BE, and PotPlayer.

The specific tag for Matroska is simply ROTATE, with a numerical value for example 90 to rotate to the right, 270 to rotate to the left, 180 to seemingly flip upside down.

The ROTATE tag must be put into the VIDEO track, not into GLOBAL. With it you could then watch your Matroska videos continually without manually rotating them for every next file.

An example XML tag is this:

<?xml version=”1.0"?>
<! — <!DOCTYPE Tags SYSTEM “matroskatags.dtd”> →
<Tags>
<Tag>
<Targets>
<TargetTypeValue>30</TargetTypeValue>
<TargetType>TRACK</TargetType>
</Targets>
<Simple>
<Name>ROTATE</Name>
<String>90</String>
<TagLanguage>eng</TagLanguage>
<DefaultLanguage>1</DefaultLanguage>
</Simple>
</Tag>
</Tags>