[linux-dvb] Re: Problem Tuning SOME channels (AVerMedia 771)

[Patrick Keane <patrick.keane@btinternet.com>]

Hi Ivor,

I found a copy of the patch you mentioned.

Just as Trevor found, when I applied it to MT352.c the first two hunks 
were OK, the third rejected.

Looking at the codes for the third hunk (This is transcribed as I have 
no way of getting stuff out of my Mythtv box 8>(( )

1. Original Mt352.c code:-

/*  here we assume 1/6Mhz == 166.66kHz stepsize */
#define IF_FREQUENCYx6 217  /* 6 * 36.16666666667Mhz */
tmp =((parm -> Frequency*3)/500000) * IF_FREQUENCY * 6;

2. The 3rd hunk patch file:-

/*  here we assume 1/6Mhz == 166.66kHz stepsize */
#define IF_FREQUENCYx6 217  /* 6 * 36.16666666667Mhz */
tmp =  6 * freq +IF_FREQUENCYx6;
tmp =  6 * (freq + IF_FREQUENCYx6);

I don't think this is correct!

What (which) should the code in the patchfile be?

regards

Patrick




Ivor Hewitt wrote:
> Patrick,
> Did you try the patch that was posted a while ago to fix the NO_LOCK 
> problem on the Avermedia cards? It fixed my problems although it sounds 
> like I had the opposite to your symptoms. i.e. 9 times out of 10 it 
> wouldn't work... but just occasionally it would lock on.
>
> I'm not sure if the patch made it into CVS and I don't have my mail list 
> to have to search for it, but I'll see if I can dig out the post.
>
> Ivor.
>
> Patrick Keane wrote:
>
> > Trevor Phillips wrote:
> >
> > > Ok, following on from the initial dramas getting this card going - I
> > > can't tune ALL the DVB-T channels available in our area. Of the 5
> > > channels/frequencies, 3 are fine, and 2 aren't.
> > >
> > > These channels tune fine under the Windows software, so it's not a
> > > signal strength issue (or at least, not SOLELY a signal strength
> > > issue).
> > >
> > > Any ideas? I've tried figuring out if there's some pattern in config
> > > options for these two dud stations, but nothing leaps out at me. Is it
> > > possible for a bleeding edge driver (mt352) to work perfectly for some
> > > stations, and not at all for others?
> > Hi Trevor,
> >
> > I TOO have an apparent intermittent "tuning" problem with my Avermedia 
> > 771 card.   At first I thought it was poor signal reception and I 
> > started looking for a new aerial, but on closer inspection it is not a 
> > signal strength problem.
> >
> > I have got my Mythtv box working using version 0.15.
> >
> > I am using all the latest ( well last week's CVS stuff) as driver 
> > sources.
> >
> > The problem is that when I boot up my HTPC, and run Myth, 9 times out 
> > of 10 I get perfect pictures sound and hours of good recordings.
> >
> > The tenth time on start up, I get a good picture and sound on the 
> > selected cahnnel for about 5 seconds then it rapidly degrades, ( 10 - 
> > 20 seconds). The final result is an oscillating picture and sound with 
> > a rep rate of about 2 second. i.e. good pic and sound then total drop 
> > out of pic and sound and back to good again.
> >
> > Switching away from the channel and back sometimes "fixes" it. More 
> > often stopping Myth front and back ends and restarting results in 
> > perfect reception FOR THAT CHANNEL. If I try going through all the 
> > channels I may or may not find another channel that exhibits the same 
> > problems, (and "fix")
> >
> > Mythtv has a setup screen with signal strength / noise bar graphs, I 
> > was lucky to catch the fault on this ... The signal strength / noise 
> > bar chart was  jumping from 70% to 10% at a one second rate.
> >
> > However if I get a good picture and sound on any channel, i.e. the 
> > fault does not occur in the first few seconds, then it stays perfect 
> > for hours!  I am sure that is nothing to do with the signal strength 
> > presented to the card.
> >
> > It is very annoying, I do not know where to look to progress diagnosis.
> >
> > If anyone can suggest any tests or even a fix I will be extremely 
> > grateful
> >
> > regards
> >
> >
> > Patrick