mencoder to capture audio from a Encore ENLTV-FM3 video capture device. I have recently noticed that, since one week ago, when the machine was forcibly restarted due to a power outage, all recordings are slightly pitched, they play back slower than they should.
I narrowed down the problem to the following command line:
$ time mencoder -really-quiet -tv driver=v4l2:device=/dev/video1:chanlist=us-cable:audiorate=32000:alsa:adevice=hw.1:input=0:amode=1:normid=11 -endpos 00:10:00 -ovc copy -oac pcm -of rawaudio -o test-32000.wav tv://69 real 9m54.886s user 0m5.536s sys 0m1.740s $ ls -l test-32000.wav -rw-r--r--@ 1 martin martin 76800000 Mar 15 17:20 test-32000.wav
mencode managed to gather precisely 10 minutes worth of raw audio in 9m 55s. That's not physically possible, unless the capture device's A/D converters are "overclocked". I can't think of any other explanation besides hardware failure. Can that be? Could it be that something got burnt during the power outage and now the capture device's internal clock went nuts?
Since the machine's restart, I've also noticed
dmesg is flooded with entries like this:
CE: hpet increased min_delta_ns to XXX nsec
Which seem to indicate that the computer's high precision event timer is somehow out of sync. Does this have to do with the audio issue? Can it be that the audio converter's sample rate is linked to the HPET? I'm totally lost here. Has anyone bumped into something similar?