On Sat, Oct 29, 2005 at 05:03:56AM +0000, Duncan Webb wrote:
> Andrew wrote:
> 
> >Sorry, i've asked before, but no answer
> >
> >I'm getting monaural sound when capturing with "cat /dev/video", and also 
> >with "cat /dev/video24"
> > 
> >
> How do you know that you're getting mono? Maybe a stupid question but it 
> could be your sound card settings or even the tv channel  if your 
> listening to the output. I did this test
> cat /dev/video24 > test.wav
> ... ^C
> aplay test.wav
> Playing raw data 'test.wav' : Unsigned 8 bit, Rate 8000 Hz, Mono

thanks, this leads to more clues:

I know it's mono only by hearing it. 

aplay thinks it is stereo, and, technically it may be, but both channels have 
identical audio (although the volume levels are different between the two 
channels), so, in effect, it is mono listening.

_______
Playing raw data './test.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, 
Stereo
-------

same result when playing directly from the device:
]# aplay -f dat /dev/video24
Playing raw data '/dev/video24' : Signed 16 bit Little Endian, Rate 48000 Hz, 
Stereo

(but, once again, the above yields monaural sound)

And I am sure the source is stereo, because i redundantly feed my tv audio out 
into my PC's line-in, and listening to it /that way/ i hear stereo. And sox 
recordings of the line-in feed are stereophonic.

The hauppauge capture is via UHF cable from the same tv (cable box)

> Then I did:
> ivtvctl --list-codec-params
> which returned:
> Segmentation fault
> and a nice Oops message in dmesg.

]# ivtvctl --list-codec-params
ioctl IVTV_IOC_G_CODEC ok
Codec parameters
aspect      : 2
audio       : 0x00e9
bframes     : 3
bitrate_mode: 0
bitrate     : 8000000
bitrate_peak: 9600000
dnr_mode    : 0
dnr_spatial : 0
dnr_temporal: 8
dnr_type    : 0
framerate   : 0
framespergop: 15
gop_closure : 1
pulldown    : 0
stream_type : 14


thanks
andrew


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