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

["Craig Procter" <cwp@mmt.com.au>]

It would be *really* useful if the CVS were actually updated with all of
the A771 patches which have been 'floating' around here on the DVB list for
the past couple of months.

Can any of the CVS moderators commit the patches to the CVS please?


-----Original Message-----
From: Patrick Keane [mailto:patrick.keane@btinternet.com]
Sent: Saturday, 11 September 2004 2:28 AM
To: Ivor Hewitt
Cc: Trevor Phillips; linux-dvb@linuxtv.org
Subject: [linux-dvb] Re: Problem Tuning SOME channels (AVerMedia 771)


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
>>
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