Media Player Classic can rotate videos around three axes, even though it doesn't have any options for rotating the video in its graphical user interface. Unlike Windows Media Player, Media Player Classic allows you to rotate your video around the X, Y and Z axes so that you can view it in landscape or portrait mode or fix it if it's upside down. Although some shortcuts are assigned to some rotation commands, you can choose which keys or shortcuts to use to rotate your videos. The player only plays back the video; you can't use it to edit and overwrite the original clip.
Open a video in Media Player Classic, click "View" and select "Options" -- or press "O" -- to display the Options window.
Select the "Keys" item from the Player group in the left pane. If the Player group is not expanded, double-click it. Locate the "PnS Rotate" commands in the Keys list.
Double-click the "Key" field of the "PnS Rotate X+" command and then press any key to rotate the video around the X axis. Rotate around the X axis to fix upside down videos. Click the "..." (ellipses) button and select "Apply" to assign the key to the command.
To use a keyboard shortcut, press several keys at the same time -- "Alt" and "Num 8" for example. To use the Num keys on the numeric keypad, Num Lock must be enabled. Enable Num Lock by pressing the "Num Lock" key in the upper-left corner of the keypad.
Assign shortcuts to all "PnS Rotate" commands. The PnS Rotate Y commands rotate the video around the Y axis. The PnS Rotate Z commands rotate the video around the Z axis. Click "Apply" to apply the new settings and select "OK" to close the Options window.
Ensure the video renderer used by Media Player Classic supports rotation. Open the Options window, select the "Output" item from the Playback group and look at the DirectShow Video section. If the Rotation feature has a green check mark, the renderer supports rotation. Select a different renderer from the menu if the Rotation feature has a red X. Click "Apply" and then "OK."
Use the keys you assigned to the PnS Rotate commands to rotate the video. You may need to press the keys several times or hold them because the rotation occurs gradually. Rotate from landscape to portrait and back by pressing "Alt-Num 1" or "Alt-Num 3.". To undo the rotation, press "Alt-Num 5."