getting input from another program

BlitzMax Forums/BlitzMax Programming/getting input from another program

Bremer

(Posted 2008) [#1]

I have some working code to start and control an external player program, but besides sending commands like pause, mute, seek and so on, I would like to receive input from it as well, such as position, lengths and so on.

The following code is something I put together by taking out some of the code from my control program. Its not complete, but it should demonstrate where my problem is and what I am after.

Type TPlayer
	Global pipe:TPipeStream

	Field process:TProcess
	Field stream:TStream

	Function createPlayer:TPlayer(hwnd:Long)
		Local this:TPlayer=New TPlayer
		Local cmd:String=PlayerPath+" dvd://1 -dvd-device "+VirtDrivePath+" -slave -colorkey 0x0A0A0A -vf scale="+scrX+":"+scrY+" -noaspect -wid "+hwnd
		this.process=TProcess.Create(cmd,0)
		this.stream=OpenStream(cmd)
		Return this
	End Function

	Method Mute()
		pipe=process.pipe
		pipe.WriteLine( "mute"+Chr(10) )	' MUTE
	End Method

	Method Seek(ff:Int)
		pipe=process.pipe
		pipe.WriteLine( "seek "+ff+Chr(10) )	' FORWARD ff SECONDS
	End Method

End Type

Rem
mute [value]
    Toggle sound output muting or set it to [value] when [value] >= 0
    (1 == on, 0 == off).
seek <value> [type]
    Seek to some place in the movie.
        0 is a relative seek of +/- <value> seconds (default).
        1 is a seek to <value> % in the movie.
        2 is a seek to an absolute position of <value> seconds.

get_time_length
    Print out the length of the current file in seconds.

get_time_pos
    Print out the current position in the file in seconds, as float.
EndRem

As you can see, if I need to send a command to the external player, I use the WriteLine command of the process module. This works just fine. But if you look at the text between the Rem/EndRem statements, you will see what the documentation tells me about getting output from the player. And this is where I am stuck. I have no idea how I would go about getting this output into my program.

Does anyone have any ideas how to get the values of get_time_length and get_time_pos?

Here is a link to the complete documentation text:

http://www.mplayerhq.hu/DOCS/tech/slave.txt

Kurator

(Posted 2008) [#2]

Method ReadLine$() 'nonblocking - returns empty string if no data available

yourString = pipe.ReadLine$()

send your command first via pipe.WriteLine and get the result with pipe.ReadLine

imagine it that your pipe has two tubes, one pointing to stdin and one to stdout

Bremer

(Posted 2008) [#3]

I had tried using ReadLine$() but for some reason unknown not in connection with the WriteLine$(), but just testing a bit, it seem to be in the right direction. Thanks.