[linux-dvb] Help! I cant view video. BUT I can scan!!

Jonas Anden jonas at anden.nu
Sun Feb 10 13:29:59 CET 2008


I haven't followed this thread from the beginning, but did you say what
kind of DVB hardware you have?

I know the Nova-TD stick is a bit picky. Too strong a signal will cause
the behavior you describe on this device. On my Nova-TD, using a good
antenna will yield no data stream (but a 100% signal), whereas if I use
the little mobile antenna that came with the stick, I get a stream but
mpeg artefacts in the picture (due to low signal).

I would try attenuating the signal (or removing amplifiers) or a
different antenna. I would also give it a shot (since you're using
mplayer to test) to use mplayer to control the whole scenario (tune,
stream-on, demux, decode and display). Try the following command:

mplayer dvb://1@TV6

Using the TV6 channel will avoid any obstacles by the channel name
containing extended-ascii (Ö) and space ... TV6 should be an unencrypted
channel and on the same MUX as TV4, even in the Öresund region ;)

  // J 

On Sat, 2008-02-09 at 01:28 +0100, Per Blomqvist wrote:
> The channel isn't encrypted.
> (I have tested with many public chanels, that I know isnt encrypted. 
> Cant get any video out)
> 
> Im Debian-tesing user, and this is a freshly installed system. On a amd64..
> (as I mentioned, in previous email)
> 
> Turns out "/dev/dvb/adapter0/dvr0" isnt the only device that doesnt work.
> (framebuffer didnt work ether, "/dev/fd0" are missing totaly, regardless 
> of bootloader vga=791 options or so).
> 
> I removed (by now mistake) older kernels when I distupgraded, cant 
> nerrow down the error search, by testing other linux-kernels.
> (since I only have one, the 2.6.22-3-amd64)
> 
> And snapshot.debian.net didnt record any older.. Only option left, to 
> start compilling by myslef.
> (but to rough)
> 
> Probably testing another distro (Ubunto) next week.
> 
> 
> CityK wrote:
> > Per Blomqvist wrote:
> >> I just signed up for this mailing-list ( I hope this is the right 
> >> forum..   
> >
> > Hi, yes, you're in the right place.
> >
> >> I can "dvbscan" and  "tzap", and gets indication of a good signal. 
> >> BUT, I cant view the video!
> >> (from the dvb device)
> >>
> >> Also "dvbdate" command works (that returns time and date from the 
> >> air, I presume). But not a command as "dvbsnoop" (that need 
> >> "/dev/dvb/adapter0/dvr").
> >>
> >> A sample: ( Its step by step of your guide:
> >> http://www.linuxtv.org/wiki/index.php/Testing_your_DVB_device )
> >>
> >> In one console I run: /.tzap# tzap -r -c channels.conf "TV4 Öresund" 
> >> ( and are getting lines as:
> >> status 1f | signal c3c3 | snr ffff | ber 0000004a | unc 00000000 | 
> >> FE_HAS_LOCK
> >> status 1f | signal c3c3 | snr ffff | ber 0000004e | unc 00000000 | 
> >> FE_HAS_LOCK
> >> ...
> >> AND in another console:
> >> mplayer -v /dev/dvb/adapter0/dvr0
> >> (thats basically halts without any further information)
> >>
> >> ALSO if I type: "cat /dev/dvb/adapter0/dvr0 > afile.txt"
> >> (But then again, "afile.txt" remains empty)
> >>
> >> Conclusion, /dev/dvb/adapter0/dvr0 never returns anything. This 
> >> "/dev/dvb/adapter0/dvr" isnt proper. Must be a Linux-kernel/module 
> >> problem..
> >>   
> >
> > Not so fast! If the channel is encrypted, this is precisely what you 
> > will observe ... though, because this is over-the-air that we're 
> > talking about, this seems less likely to be the case (but you will 
> > have to confirm nonetheless).  
> > I'm more inclined to think that this is related to an issue with 
> > stream identifiers.  Is Sweden using MP4 now? Some further questions, 
> > what drivers are you using (distro or recent LinuxTV)?
> > What dvb-apps ... Christophe had updated the dvb-apps not to long ago 
> > with some changes in regards to MP4 streams (can't remember the exact 
> > nature, but perhaps you should grab a new copy from LinuxTV and try 
> > with those).
> >
> Whatever frontend I test, it will not work.
> The device, never stream anything.
> 
> I can tune, but not view the video.
> (thats it)
> 
> 




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