Пакет: удалить расширение файла

Вы можете использовать %% ~ nf , чтобы получить имя файла, только как описано в справке для для :

@echo off
    for /R "C:\Users\Admin\Ordner" %%f in (*.flv) do (
    echo %%~nf
)
pause

Доступны следующие параметры :

Variable with modifier  Description

%~I                     Expands %I which removes any surrounding 
                        quotation marks ("").
%~fI                    Expands %I to a fully qualified path name.
%~dI                    Expands %I to a drive letter only.
%~pI                    Expands %I to a path only.
%~nI                    Expands %I to a file name only.
%~xI                    Expands %I to a file extension only.
%~sI                    Expands path to contain short names only.
%~aI                    Expands %I to the file attributes of file.
%~tI                    Expands %I to the date and time of file.
%~zI                    Expands %I to the size of file.
%~$PATH:I               Searches the directories listed in the PATH environment 
                        variable and expands %I to the fully qualified name of 
                        the first one found. If the environment variable name is 
                        not defined or the file is not found by the search,
                        this modifier expands to the empty string.