[linux-dvb] Unwatchable channels and strange behaviour of Hauppauge Nova-T Stick (update)

José Oliver Segura primijos at gmail.com
Mon Dec 18 23:31:48 CET 2006

On 12/18/06, José Oliver Segura <primijos at gmail.com> wrote:
> On 12/18/06, Luca Olivetti <luca at ventoso.org> wrote:
> > En/na José Oliver Segura ha escrit:
> > >
> > >       Anyway, as you said, the interesting point is that the TVE mux
> > > seems to be a problematic one doesn't matter wich location/card (only
> > > being important using the native windows driver or the linux one in my
> > > case). I don't know if this can give us any clue to start doing some
> > > research (once some days ago I was convinced that Higher frequencies
> > > where causing reception problems but, again, today I've found that it
> > > doesn't matter: I can watch channels transmitted at higher
> > > frequencies)
> >
> > Another "interesting" thing with the TVE mux: I'm not sure I'm correctly
> > managing the performance counters of my usb stick, but basically there
> > are 2 post viterbi counters: an "abort count"  (i.e. uncorrectable
> > packets) and an "error count " (number of error bits). By touching the
> > screen on the coaxial cable I managed to keep both counters at 0, still
> > the image is full of artifacts.
> > I remember seeing the same on some satellite channels: no uncorrectable
> > errors but still there are many artifacts.
> > Maybe they're using some non standard mpeg encoding (that both xine and
> > mplayer are unable to handle)?
>        More on this: when I'm not able to tune "TVE 1", with femon I
> can see that the only bit not active in status is the "V" (viterbi?).
> I'm not sure what that means, but regarding the "non standard mpeg"
> possibility, I'm afraid it is not sure: sometimes I can tune and watch
> "TVE 1" without any problem (with mplayer), so... it seems that, when
> "watchable", this MPEG stream is OK for mplayer.

       Update: a simple experiment with this mux reveals (I think)
that there's no problem with the signal strenght or mpeg stream, but
with the driver. Experiment is simple: whenever this problem appears
(can't tune "TVE 1" -> mplayer time out + femon shows missing "V" bit
in status), I just need to "rmmod dvb_usb_dib0700" and "modprobe
dvb_usb_dib0700" and then everything works again... (maybe I'm to
simple, but I think this restricts the problem to a software problem)

       Maybe there's some code at module init time that needs to be
called everytime? Or maybe the first tunning/disconnect let the stick
in a state in which it is not able to tune 100% that frequency?

       Anybody has any idea to point me in the right direction to
start looking/getting info?


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