[linux-dvb] [PATCH] Siemens DVB-C PCI: SAA7113 Analog Module, on integrating msp3400.c, fixing stereo

Anders Gunnarsson d00guan at dtek.chalmers.se
Mon Jul 18 23:17:11 CEST 2005


thomas schorpp wrote:

>Anders Gunnarsson wrote:
>  
>
>>thomas schorpp wrote:
>>
>>    
>>
>>>anyway the msp3400 chip of this card shouldnt be used for dvb audio,
>>>cause the sound output in that way is heavily harmonic distorted and the
>>>proposed "volume setting for dvb with onboard analog mogule" does NOT
>>>work here anyway, at least not with vdr... so we should drop dvb usage
>>>for it. spdif soundcards are cheap nowadays.
>>>
>>> 
>>>
>>>      
>>>
>>The volume setting in vdr worked fine for me the few time I got the
>>msp3400 working with current sources. When it was working I didn't
>>notice any distortion, at least not more noticable than the quantisation
>>noise in analog output without the module.
>>    
>>
>
>for me:
>
>-not with vdr 1.3.27
>
>and others:
>
>-connecting the audio out to soundcard or hifi equipment, the harmonic
>distortion of this output IS significant (can listen about >10%), not
>only for my card, others reported too and its stated even in vdr wiki.
>
>  
>
When I last tried the analog module I used it for 2-3 days straight and 
my experience was that the sound was significally better than without 
the module. I tested with VDR 1.2.6 and 1.3.12. I got it working after a 
long power-off and with a lot of luck. :)

Maybe it differs with different versions of the chip or something else. 
Mine is an MSP 3403C A1. Don't remember the version number from the 
recognision.

Might also depend on if the level of the outputsignal from the dvb-card 
is to high for the soundcard input. I use an integrated SB16 and can 
have full volume in VDR and full in and out on the sound card without 
distortion, that is with the current settings in the dvb drivers. The 
output with analog module and full volume is a bit higher than without.

However when I tested the Siemens drivers in Windows I tested the 
capabilites of analog tv, and the sound there was really crappy. With 
Techno Trends drivers dvb worked fine with volume control and all, but 
with a bit of distorsion. Don't know if the analog module is used then 
or not, but guess so since volume control works in their software.

>>Haven't had time to check more what the detection-problem is, but it
>>should also be solvable in the old code.
>>    
>>
>
>the problem is, the code is insufficent for this chip (tried several
>hours, will no more, its too complex and risky -> uneconomical redesign
>effort), does not belong to that file, supports not mostly used
>international tv-standards (says only pal B/G). this is the job of a
>specialized driver.
>since theres one yet, i wont reinvent the wheel ;)
>
>  
>
Maybe I came out a bit wrong. I'm very glad that someone takes the time 
to fix the drivers for the analog module. I agree that new code is 
needed, it would be great if all features could be used through VDR and 
if all settings was trimed to get it work as good as possible.

Tell me if I can help with something, I've got the datasheet and am a 
quite skilled software developer, just not for linux drivers yet. :P

/Anders
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