• Download VirtualDub
• Download XVid codec
• How to capture video from command prompt
  • Open CMD
  • Make sure you are at the VirtualDub direcctory.
  • Write the following at the command prompt
    • virtualdub /capture /capdevice screen capture /min /capfile CapVidFile_%date:~10,4%%date:~4,2%%date:~7,2%%time:~-2,2%%date:~-4,2%%date:~-7,2%.avi /capstart /x
    • Flags and options to use
      • /capture
      • /capdevice
      • /min
      • /capfile
        • Captured file name formatting to include date and time.
          • CapVidFile_%date:~10,4%%date:~4,2%%date:~7,2%%time:~-2,2%%date:~-4,2%%date:~-7,2%.avi
      • /capstart
      • /x

Here are command prompt options for VirtualDub

• Displays, sets, or removes cmd.exe environment variables.

  SET [variable=[string]]

  variable Specifies the environment-variable name.
  string Specifies a series of characters to assign to the variable.

  Type SET without parameters to display the current environment variables.

  If Command Extensions are enabled SET changes as follows:

  SET command invoked with just a variable name, no equal sign or value
  will display the value of all variables whose prefix matches the name
  given to the SET command. For example:

  SET P

  would display all variables that begin with the letter ‘P’

  SET command will set the ERRORLEVEL to 1 if the variable name is not
  found in the current environment.

  SET command will not allow an equal sign to be part of the name of
  a variable.

  Two new switches have been added to the SET command:

  SET /A expression
  SET /P variable=[promptString]

  The /A switch specifies that the string to the right of the equal sign
  is a numerical expression that is evaluated. The expression evaluator
  is pretty simple and supports the following operations, in decreasing
  order of precedence:

  () – grouping
  ! ~ – – unary operators
  * / % – arithmetic operators
  + – – arithmetic operators
  << >> – logical shift
  & – bitwise and
  ^ – bitwise exclusive or
  | – bitwise or
  = *= /= %= += -= – assignment
  &= ^= |= <<= >>=
  , – expression separator

  If you use any of the logical or modulus operators, you will need to
  enclose the expression string in quotes. Any non-numeric strings in the
  expression are treated as environment variable names whose values are
  converted to numbers before using them. If an environment variable name
  is specified but is not defined in the current environment, then a value
  of zero is used. This allows you to do arithmetic with environment
  variable values without having to type all those % signs to get their
  values. If SET /A is executed from the command line outside of a
  command script, then it displays the final value of the expression. The
  assignment operator requires an environment variable name to the left of
  the assignment operator. Numeric values are decimal numbers, unless
  prefixed by 0x for hexadecimal numbers, and 0 for octal numbers.
  So 0x12 is the same as 18 is the same as 022. Please note that the octal
  notation can be confusing: 08 and 09 are not valid numbers because 8 and
  9 are not valid octal digits.

  The /P switch allows you to set the value of a variable to a line of input
  entered by the user. Displays the specified promptString before reading
  the line of input. The promptString can be empty.

  Environment variable substitution has been enhanced as follows:

  %PATH:str1=str2%

  would expand the PATH environment variable, substituting each occurrence
  of “str1” in the expanded result with “str2”. “str2” can be the empty
  string to effectively delete all occurrences of “str1” from the expanded
  output. “str1” can begin with an asterisk, in which case it will match
  everything from the beginning of the expanded output to the first
  occurrence of the remaining portion of str1.

  May also specify substrings for an expansion.

  %PATH:~10,5%

  would expand the PATH environment variable, and then use only the 5
  characters that begin at the 11th (offset 10) character of the expanded
  result. If the length is not specified, then it defaults to the
  remainder of the variable value. If either number (offset or length) is
  negative, then the number used is the length of the environment variable
  value added to the offset or length specified.

  %PATH:~-10%

  would extract the last 10 characters of the PATH variable.

  %PATH:~0,-2%

  would extract all but the last 2 characters of the PATH variable.

  Finally, support for delayed environment variable expansion has been
  added. This support is always disabled by default, but may be
  enabled/disabled via the /V command line switch to CMD.EXE. See CMD /?

  Delayed environment variable expansion is useful for getting around
  the limitations of the current expansion which happens when a line
  of text is read, not when it is executed. The following example
  demonstrates the problem with immediate variable expansion:

  set VAR=before
  if “%VAR%” == “before” (
  set VAR=after
  if “%VAR%” == “after” @echo If you see this, it worked
  )

  would never display the message, since the %VAR% in BOTH IF statements
  is substituted when the first IF statement is read, since it logically
  includes the body of the IF, which is a compound statement. So the
  IF inside the compound statement is really comparing “before” with
  “after” which will never be equal. Similarly, the following example
  will not work as expected:

  set LIST=
  for %i in (*) do set LIST=%LIST% %i
  echo %LIST%

  in that it will NOT build up a list of files in the current directory,
  but instead will just set the LIST variable to the last file found.
  Again, this is because the %LIST% is expanded just once when the
  FOR statement is read, and at that time the LIST variable is empty.
  So the actual FOR loop we are executing is:

  for %i in (*) do set LIST= %i

  which just keeps setting LIST to the last file found.

  Delayed environment variable expansion allows you to use a different
  character (the exclamation mark) to expand environment variables at
  execution time. If delayed variable expansion is enabled, the above
  examples could be written as follows to work as intended:

  set VAR=before
  if “%VAR%” == “before” (
  set VAR=after
  if “!VAR!” == “after” @echo If you see this, it worked
  )

  set LIST=
  for %i in (*) do set LIST=!LIST! %i
  echo %LIST%

  If Command Extensions are enabled, then there are several dynamic
  environment variables that can be expanded but which don’t show up in
  the list of variables displayed by SET. These variable values are
  computed dynamically each time the value of the variable is expanded.
  If the user explicitly defines a variable with one of these names, then
  that definition will override the dynamic one described below:

  %CD% – expands to the current directory string.

  %DATE% – expands to current date using same format as DATE command.

  %TIME% – expands to current time using same format as TIME command.

  %RANDOM% – expands to a random decimal number between 0 and 32767.

  %ERRORLEVEL% – expands to the current ERRORLEVEL value

  %CMDEXTVERSION% – expands to the current Command Processor Extensions
  version number.

  %CMDCMDLINE% – expands to the original command line that invoked the
  Command Processor.

  %HIGHESTNUMANODENUMBER% – expands to the highest NUMA node number
  on this machine.