[mythtv-users] Stereo sound with PVR-250

Tue Oct 19 22:54:26 UTC 2004

Mats Cedergren wrote:

>-----Original Message-----
>From: Joseph A. Caputo [mailto:jcaputo1 at comcast.net]
>Sent: Mon 10/18/2004 3:52 PM
>To: Discussion about mythtv
>Subject: Re: [mythtv-users] Stereo sound with PVR-250
> 
>Note: please don't top-post.  See below.
>
>On Friday 15 October 2004 17:28, Mats Cedergren wrote:
>  
>
>>From: Joseph A. Caputo [mailto:jcaputo1 at comcast.net]
>>    
>>
>>>Sent: Fri 10/15/2004 11:01 PM
>>>To: Discussion about mythtv
>>>Subject: Re: [mythtv-users] Stereo sound with PVR-250
>>>
>>>On Friday 15 October 2004 15:39, Mats Cedergren wrote:
>>>      
>>>
>>>>Is anybody getting stereo sound with there PVR-250 cards under
>>>>linux? I only get mono :(
>>>>        
>>>>
>>>What are you recording from?  Tuner or A/V in?  If you're recording
>>>from the tuner, then the problem is probably your audio output, not
>>>the -250.  If the -250 is really recording mono sound and the source
>>>is definitely stereo, then you've got a bad card.
>>>
>>>More likely, either (1) you've misconfigured your tuner type, (1a) 
>>>      
>>>
>or
>  
>
>>>if you're not using the tuner, does your audio input to the PVR-250
>>>have a stereo plug?, or (3) your recordings are just fine, but there
>>>is a problem with the way your audio output is configured, which has
>>>nothing to do with the PVR-250.  To check (3), try playing a
>>>recording on a different machine.
>>>
>>>-JAC
>>>
>>>
>>>I'm recordning from the Tuner. I have tried the same card in
>>>WindowsXP (the same computer, dual boot setup) and there the card
>>>works perfectly and I get stereo sound from all channels that
>>>transmit in stereo.
>>>
>>>I have not tried the recordning on another computer yet, will try
>>>that tomorrow, but I don't think that it will make any difference.
>>>When I play music or other movies (.avi, .mpg, dvd etc) i get stereo
>>>sound.
>>>      
>>>
>
>  
>
>>When you play them with what?  Myth's internal player?  I assume you're 
>>playing them with other programs (mplayer, xine, etc).  So all that 
>>tells us is that there's nothing wrong with your sound card or driver.
>>    
>>
>
>  
>
>>Now we need to make sure that Myth is properly configured for sound 
>>output.  The best way to do this is to take a known good file (like a 
>>'good' .avi or .mpg file with stereo sound) and play it using Myth's 
>>internal player with the command "mythtv <filename>".  If you get 
>>stereo sound here (and I bet you will), then your sound output is 
>>configured properly within Myth.
>>    
>>
>
>I have tried playing them with both internal mythtv player and with mplayer
>and with vlc. None of the players produced stereo from files recorded with
>mythtv. However, if I playback an avi file with "mythtv <filename>" I do get
>
>stereo as you guessed.
>
>  
>
>>>When I play a video captured with "cat /dev/video0 > /tmp/test.mpg"
>>>using mplayer "mplayer /tmp/test.mpg" it reports that the file have
>>>two channel sound but I can hear that the sound is not in stereo.
>>>      
>>>
>
>  
>
>>This sounds like there's a problem with your ivtv driver setup, or with 
>>your input source.  Since you say you've rebooted the same setup into 
>>Windows and heard stereo, I'm guessing that your input source is OK.  
>>Therefore I'm guessing there is some problem with your ivtv driver 
>>setup.  Try playing with the test_ioctl program to query/change the 
>>capture settings for your card (you'll probably need to quit 
>>mythbackend to do this).  Specifically, look at the "-A" option, which 
>>sets the audio capture mode to Mono, Stereo, Lang2/SAP or Lang1.  I'm 
>>afraid this is a bit out of my area of expertise; I suppose it's 
>>possible that something is putting your card in Mono capture mode; 
>>perhaps your card is being mis-identified by the ivtv driver; in that 
>>case, you might need to pass some parameters to the driver via the /
>>etc/modules.conf file.  You might want to ask on the ivtv-users list; 
>>make sure to have the specific specs of your card handy (i.e., the 
>>output of "lspci").
>>
>>HTH,
>>
>>JAC
>>    
>>
>
>  
>
>>I to starting to beleave there is something wrong with my ivtv driver.
>>    
>>
>
>  
>
>>Here are some of my test results:
>>    
>>
>
>  
>
>>I tune to a channel that I know does NOT send in stereo:
>>    
>>
>
>  
>
>>[mythtv at localhost mythtv]$ test_ioctl -Z
>>ioctl: VIDIOC_G_TUNER
>>current audio mode   : 1
>>  (stereo 1, lang1 3, lang2 2, mono 0)
>>available subchannels: 0x1
>>  (stereo 0x2, lang1 0x8, lang2 0x4, mono 0x1)
>>
>>However if I tune to channel that does send in stereo:
>>[mythtv at localhost mythtv]$ test_ioctl -Z
>>ioctl: VIDIOC_G_TUNER
>>current audio mode   : 1
>>    
>>
> >  (stereo 1, lang1 3, lang2 2, mono 0)
>  
>
>>available subchannels: 0x2
>>  (stereo 0x2, lang1 0x8, lang2 0x4, mono 0x1)
>>    
>>
>
>  
>
>>This clearly shows that the card/drivers correctly detects when a channel
>>does sends in stereo.
>>    
>>
>
>  
>
>>I'm running with 2.6.x kernel, it might have something to do with that? I
>>thinkt
>>I will try with the ivtv-user lists since it seems that my trouble are
>>related to
>>the driver and not mythtv.
>>    
>>
>
>  
>
>>/Mats
>>    
>>
>
>
>Update:
>It think that I found a workaround for my problem. Here is what I did:
> 
>I downloaded and installed "ivtv-0.1.10-pre2-ck100z",rebooted the computer
>and
>was still getting mono audio. I downloaded new firmware file and extracted
>it 
>with "ivtvfwextract.pl" (don't know if I have to do anything else, the
>extracted 
>files are now locateded in /lib/modules?). Run "ivtvclt -H" to reloade
>firmware
>(don't know if it makes any difference).
>After all this I was still getting mono sound. 
>I was playing around with ivtvctl's different settings when I all the sudden
>
>found myself listening to stereo sound. Big joy :) 
>Rebooted the computer to see if I still was getting stereo sound but no
>luck, back
>to mono again. I remember that I was playing with "-z" and "-Z" parameter so
>I first
>run "ivtvctl -z 0" and then "ivtvctl -z 1" and BINGO!! Stereo sound again. 
>
>I think there is a bug/error in the driver that prevents the card from
>operating 
>correctly and my litte trick with "-z" parameter corrects the problem for
>me.
>
>/Mats C
>
Interesting.. from the doc, that means you are listening to the SAP and 
not the main audio.
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