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From: J G Miller on 16 Apr 2010 13:13
Op Vrijdag, 16 April, 2010 18:20:09h +0200, Houghi schreef:

> 1) Is /dev/video0 busy or not.

Surely you want to use fuser?

For example:


> fuser /dev/snd/controlC0

/dev/snd/controlC0: 4255


-----------------------------------<snip>--------------------------
#! /bin/sh

device="/dev/video0"

pid="`fuser ${device} 2>&1 | sed -e 's|'"${device}"':[ ]*||'`"

if [ -z "${pid}" ]
then

echo "system device ${device} is not busy"

... whatever else you want to do

else

echo "system device ${device} is busy and is being used by process ${pid}"

... whatever else you want to do

fi

exit 0
--------------------------------------<snip>---------------------------------------

Note that in the sed expression in the [] there should be a
<SPACE> and a <TAB> to mop up any white space.
From: Malcolm on 16 Apr 2010 13:15
On Fri, 16 Apr 2010 18:20:09 +0200
houghi <houghi(a)houghi.org.invalid> wrote:

> I am trying to work out the following and get it into a parameter in
> bash:
> 1) Is /dev/video0 busy or not.
> I get the following:
> houghi(a)penne : head -n 1 /dev/video0
> head: error reading `/dev/video0': Device or resource busy
>
> How can I get that error message in a variable?
Hi
You could just use stderr (Device or resource busy) error number 16 as
an exit code?

--
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SUSE Linux Enterprise Desktop 11 (x86_64) Kernel 2.6.27.45-0.1-default
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From: J G Miller on 16 Apr 2010 15:16
Op Vrijdag, 16 April, 2010 20:47:57 +0200, Houghi schreef:

> so only the ability to see what MPlayer is playing as movie

Assuming it is a file, you could get this from the command line
argument if it was invoked as "mplayer filename"

cat /proc/${mplayer_pid}/cmdline

See now why having the PID of the process keeping /dev/video0
busy might be a good thing to have in your script?

Or you could do a lsof | egrep mplayer and eliminate
all the shared libraries etc and what is left will be the file
which it is playing. If your media files are always under
a particular directory, then that would be more direct with

lsof | egrep mplayer | egrep path_to_media_files

> The frequency is not 100% correct as it always ends with .25000

Chop it off with cut or sed.
From: JT on 19 Apr 2010 03:51
On 16/04/10 22:16, houghi wrote:
> J G Miller wrote:
>
>> Assuming it is a file, you could get this from the command line
>> argument if it was invoked as "mplayer filename"
>>
>> cat /proc/${mplayer_pid}/cmdline
>>
> That won't work as I will start it with `mplayer /dev/video0` and then
> open a movie. However /proc/${mplayer_pid}/fd will have the file in
> question.
>
>
>> See now why having the PID of the process keeping /dev/video0
>> busy might be a good thing to have in your script?
>>
> For /dev/video0 the PID is not importand. Either it is used, or it
> isn't. Retrieving the PID does not mean anything.
>
>
>> Or you could do a lsof | egrep mplayer and eliminate
>> all the shared libraries etc and what is left will be the file
>> which it is playing. If your media files are always under
>> a particular directory, then that would be more direct with
>>
>> lsof | egrep mplayer | egrep path_to_media_files
>>
> No, they are not in one specific directory.
> I got it working with:
> basename `lsof |grep ^gmplayer|grep REG|grep 10u|awk '{print $NF}'`
>
> However doing some tests it is clear that this is useless information.
> If I get: A_BRIDGE_TO_FAR_D1245_VAM_03.avi it does not mean anything.
>
> Sure, the name of the movie is clear, but not that it is one of the
> extra's. So the only thing I could do is make a database with all the
> files, look up with the file (including the directory) if I can find it
> and then retrieve the apropriate inforamtion.
>
> Way too much work. Thanks anyway.
>
> houghi
>
Good work, maybe 'dbus' or the like might help to query mplayer for more
info?

--
Kind regards, JT

From: JT on 19 Apr 2010 11:08
On 19/04/10 15:32, houghi wrote:
> JT wrote:
>
>> Good work, maybe 'dbus' or the like might help to query mplayer for more
>> info?
>>
> Could be, but I have no idea where to start. And all that a search has
> brought up with dbus is gnome-mplayer, which I do not have.
>
> I looked with qdbusviewer and found nothing that looked like mplayer.
>
> houghi
>
't Was only an idea, sorry to put you on the wrong track. Dbus doesn't
show mplayer here either, hadn't checked that.

I tried 'lsof', which does give a listing of all open files by process
when using 'lsof -p <pid-of-your-player>'.

Maybe that helps?


--
Kind regards, JT

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