[mythtv] [mythtv-commits] Ticket #1104: multichannelaudio support

Paul Catchpole paul at paulcatchpole.co.uk
Tue Jan 1 00:19:03 UTC 2008


Paul Catchpole wrote:
> Paul Catchpole wrote:
>   
>> Mark Spieth wrote:
>>   
>>     
>>>> I've one problem with it, now we've been using it for a few hours - I'm
>>>> getting a crackle from the centre speaker which is intermittent although
>>>> not random. It varies from a sharp click, to a buzz and is in sync with
>>>> the sound on the channel. It has the following characteristics:
>>>>
>>>> * Master output volume level changes the volume of the click, but
>>>> doesn't alter its proportion to the other sounds.
>>>> * Changing the centre channel mixer level makes the clicking quieter,
>>>> but doesn't alter its proportion to the other sounds on the centre 
>>>> channel.
>>>>
>>>> I'm getting the feeling that it is directly proportional to the quantity
>>>> of very low frequency sounds in the source. It was particularly bad
>>>> earlier on 'Creature Comforts' and is extremely bad, now and again,
>>>> watching [well, my better half is] the X-Factor. Commercials almost
>>>> always don't cause it. It does happen on the news channels.
>>>>
>>>> I know that's perhaps not a lot to go on, but if you've any ideas I'd
>>>> appreciate it.
>>>>     
>>>>       
>>>>         
>>> in el_surround.cpp line 74 (setting wnd in loop with sqrt) there is a 0.5 
>>> commented out. uncomment it so that the 0.5 factor is included. I suspect 
>>> the clicking is float to short conversion issues. this will decrease the 
>>> overall gain of the upmixer. let me know if it works for you. everything Ive 
>>> tested with shows the current value ok but more testing will prove/disprove 
>>> this.
>>>
>>> mark
>>>
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>>>   
>>>     
>>>       
>> I've made the change - in el_processor.cpp, you meant?
>>
>> Recompiling now - I'll let you know how I get on.
>>
>> The clicking is an odd one. Jurassic Park went by with no clicking 
>> whatsoever, but Red Dwarf on BBC2 was awful. Odd!
>>
>> PC
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>> mythtv-dev at mythtv.org
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>>   
>>     
> Been using it all afternoon with no clicking whatsoever. Noticed the 
> gain loss though - although it isn't really a problem!
>
> Cheers!
>
> Paul
>
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>   

On Mon, 31 Dec 2007 12:46:59 -0000
"MythTV" <mythtv at cvs.mythtv.org> wrote:


> > 40 fixes up gain values
>   

Patch 40 works well for us here... Gain is back to usual too - haven't
needed to play with the relative mixer settings yet. 

Mythmusic is segfaulting on startup at the moment, but I've not rebuilt it for a while, so I'm doing that now. 

Is it worth me recompiling with built-in AC3 support?

Cheers again, Mark. 

PS: Happy new year! 

PC



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