> From: [email protected]
> To: [email protected]
> Date: Fri, 12 Feb 2010 20:52:28 -0500
> Subject: Re: [ivtv-users] hvr-1600, frame CRC mismatch - incomplete frame
>
> On Fri, 2010-02-12 at 16:26 -0500, Kyle Lil wrote:
> > Thanks, Devin. Below is the output of azap. I'm assuming that the
> > errors are occurring at the same time the video/audio glitches would
> > be. I think it is slightly worse on some channels than on others (but
> > not drastically). The example below is from one of the worse
> > channels.
> >
> > using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
> > tuning to 799789900 Hz
> > video pid 0x0000, audio pid 0x0000
> > status 00 | signal 0000 | snr 0000 | ber 00000000 | unc 00000000 |
> > status 1f | signal 013e | snr 013e | ber 000019a7 | unc 000019a7 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000267 | unc 00000267 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000264 | unc 00000264 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0146 | snr 0146 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
> > status 1f | signal 0145 | snr 0145 | ber 00000000 | unc 00000000 |
> > FE_HAS_LOCK
>
>
> This looks like EMI of some sort to me. (Either that or some tracking
> loop in the digital tuner or demod losing lock - but then SNR would
> likely dip).
>
> EMI might be coming from inside the PC. Does your computer under linux
> happen to write to disk every 30 seconds or so?
>
>
> Regards,
> Andy
>
>
>
> _______________________________________________
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> [email protected]
> http://ivtvdriver.org/mailman/listinfo/ivtv-users
The hard drive is being accessed pretty frequently (~1/second) when watching tv
with mythtv, much more often than the errors are appearing. So, the hard drive
cannot reliably produce the errors. Interestingly, I think the errors seem to
occur slightly more often when watching tv with myth than when just monitoring
the signal with azap. Would azap catch all errors or does it just sparsely
sample the signal?
The optical drive is not spinning up and the graphics card is fanless. The only
other significant EMI sources inside the computer that I can think of are the
case fan, cpu fan, and maybe the power supply. I can play around with different
ground configurations to see if that helps.
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