[vdr] Re: GRAB always gives gray image

[Jan Ekholm <chakie@infa.abo.fi>]

On Tue, 2 Mar 2004 oliviervdr@free.fr wrote:

>> I experimented a bit with the SVDRP command GRAB to get screenshots, but
>> it always seems to return a solid gray image, such as this one:
>>
>>     http://www.infa.abo.fi/~chakie/media/dvb/test.jpg
>
>Jan,
>
>do you have another v4l device on your PC (like analog TV card)?

No other cards, only one DVB-c card.

>If yes, then this should be fixed since 1.2.6pre1 (and you have 1.3.5).
>(from HISTORY:
>- Fixed detecting the /dev/videoN devices for GRAB in case there are others
>  before the DVB devices (thanks to Andreas Kool).
>)
>
>You could take a look at cDvbDevice::GrabImage in dvbdevice.c and try to
>override devVideoIndex variable to see if it is wrongly set.
>If you succeed, then we should try to look why this doesn't work for you.

It seems to use:

	device index: 0, device name: /dev/video0

which is correct on this system. Right now when I test (remotely) I can't
get a single GRAB to work, it just freezes VDR and then the watchdog
performs an emergency exit.

Doing a reboot now... Ok, that cured the grabbing problems, now I get the
same gray images again.

Another thing I noticed while monitoring VDR is that it has started to
take a lot more CPU than before (not sure since when). Not one thread sits
in a tight loop and does nothing more than this:

select(1024, [23], NULL, NULL, {0, 10000}) = 0 (Timeout)
time(NULL)                              = 1078300591
gettimeofday({1078300591, 801847}, NULL) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [RTMIN], 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN], [RTMIN], 8) = 0
gettimeofday({1078300591, 802801}, NULL) = 0
nanosleep({0, 9046000}, NULL)           = 0
rt_sigprocmask(SIG_SETMASK, [RTMIN], NULL, 8) = 0
alarm(60)                               = 60
time(NULL)                              = 1078300591
time(NULL)                              = 1078300591
time(NULL)                              = 1078300591

I'm not sure what descriptor 23 is, but it seems to wait for access to
that descriptor. This keeps on running as long as VDR is alive, and does
not seem to have any negative effects apart from hogging 25% of the CPU
(an Epia 800) all the time. Some more tests show that the function can
also be accept() instead of select().

Weird.

Regards,
    Jan Ekholm

-- 

    Greebo could, in fact, commit sexual harrassment simply by sitting
                    very quietly in the next room.
                                             -- Terry Pratchett, Maskerade


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