I searched and found that this (or something similar) was reported back in
August: I get intermittent tinny sound in some of my MythTV recordings.
This is in a system that I set up almost two years ago. Then, it was an
FC6, myth-0.20 install with whatever the latest stable IVTV drivers from
atrpms were. I never had an audio quality problem under this software
setup. A few weeks ago, the root drive on that system died, so I don't
know exactly what IVTV version I was using then (I failed to back up the
root drive anywhere).
When I got a new root drive, I installed FC9, which installed with a
kernel-2.6.25-14 (x86_64 in case it matters), which includes the ivtv
driver already. I installed ivtv-firmware-20080701 and ivtv-utils-1.2.0-6.
I got mythtv back up running, but found that some new recordings had an
irritating tinny quality (distorted high frequencies). Initially, this
seemed to be happening on about 50% of recordings.
I downloaded the "bleeding edge" module source on 12/2, compiled and
installed the new modules, and if I look at the last 15 mythtv recordings,
it looks like 20-25% of recordings are tinny.
Yesterday, I had a chance to try some debugging. I found that if I ran
something like:
for num in {0,1}{0,1,2,3,4,5,6,7,8,9}
do
cat < /dev/video1 > /myth/tmp/file$num.mpg &
pid=${!}
sleep 5
kill -INT $pid
wait $pid
sleep 3
done
I would get 1-3 files with the tinny quality.
The August "Tininess From RCA Stereo Jacks on PVR-150" thread suggested
trying a "v4l2-ctl --set-audio-input=1" when the sound was distorted to see
if it would go away. I inserted this into the above loop:
...
pid=${!}
sleep 5
v4l2-ctl -d /dev/video1 --set-audio-input=1
sleep 5
kill -INT $pid
...
and then ran 100 times. In the first 67 recordings, I got 6 occurrences of
a recording with the tinny sound at the beginning, and in each of those,
after 5 seconds the sound returns to normal. Furthermore, for all of the
other 61 recordings that sounded fine, they sounded fine all the way
through. So, --set-audio-input=1 initiated after the recording starts,
appears to put the driver into the non-tinny state if it is tinny, and
doesn't cause a problem if the driver was already in the non-tinny state.
I added set-audio-input to my channel-change script for now. I placed one
of the 6 tinny+workaround recordings at:
http://roonabeck.bellsofireland.com/file65.mpg
The first 5 seconds sound tinny, and the next 5 seconds sound fine.
Starting with the 68th recording, and for every recording after that, the
sound became terribly distorted. I have no idea what caused this, and I
never had a mythtv recording that sounded like this before. Something
apparently became corrupted such that I had to unload and reload the module
to clear the problem, because even a mythtv recording started with the
card/driver in this state also had the same distortion. I placed a sample
of this at:
http://roonabeck.bellsofireland.com/file67.mpg
I haven't tried to reproduce this again, but thought I'd mention it. I'm
really just interested in trying to get to the bottom of the tinny audio
problem, unless this other distortion also becomes a recurring problem.
Please let me know what I can do to help narrow down the problem.
Thanks,
Noah
_______________________________________________
ivtv-devel mailing list
ivtv-devel@ivtvdriver.org
http://ivtvdriver.org/mailman/listinfo/ivtv-devel
August: I get intermittent tinny sound in some of my MythTV recordings.
This is in a system that I set up almost two years ago. Then, it was an
FC6, myth-0.20 install with whatever the latest stable IVTV drivers from
atrpms were. I never had an audio quality problem under this software
setup. A few weeks ago, the root drive on that system died, so I don't
know exactly what IVTV version I was using then (I failed to back up the
root drive anywhere).
When I got a new root drive, I installed FC9, which installed with a
kernel-2.6.25-14 (x86_64 in case it matters), which includes the ivtv
driver already. I installed ivtv-firmware-20080701 and ivtv-utils-1.2.0-6.
I got mythtv back up running, but found that some new recordings had an
irritating tinny quality (distorted high frequencies). Initially, this
seemed to be happening on about 50% of recordings.
I downloaded the "bleeding edge" module source on 12/2, compiled and
installed the new modules, and if I look at the last 15 mythtv recordings,
it looks like 20-25% of recordings are tinny.
Yesterday, I had a chance to try some debugging. I found that if I ran
something like:
for num in {0,1}{0,1,2,3,4,5,6,7,8,9}
do
cat < /dev/video1 > /myth/tmp/file$num.mpg &
pid=${!}
sleep 5
kill -INT $pid
wait $pid
sleep 3
done
I would get 1-3 files with the tinny quality.
The August "Tininess From RCA Stereo Jacks on PVR-150" thread suggested
trying a "v4l2-ctl --set-audio-input=1" when the sound was distorted to see
if it would go away. I inserted this into the above loop:
...
pid=${!}
sleep 5
v4l2-ctl -d /dev/video1 --set-audio-input=1
sleep 5
kill -INT $pid
...
and then ran 100 times. In the first 67 recordings, I got 6 occurrences of
a recording with the tinny sound at the beginning, and in each of those,
after 5 seconds the sound returns to normal. Furthermore, for all of the
other 61 recordings that sounded fine, they sounded fine all the way
through. So, --set-audio-input=1 initiated after the recording starts,
appears to put the driver into the non-tinny state if it is tinny, and
doesn't cause a problem if the driver was already in the non-tinny state.
I added set-audio-input to my channel-change script for now. I placed one
of the 6 tinny+workaround recordings at:
http://roonabeck.bellsofireland.com/file65.mpg
The first 5 seconds sound tinny, and the next 5 seconds sound fine.
Starting with the 68th recording, and for every recording after that, the
sound became terribly distorted. I have no idea what caused this, and I
never had a mythtv recording that sounded like this before. Something
apparently became corrupted such that I had to unload and reload the module
to clear the problem, because even a mythtv recording started with the
card/driver in this state also had the same distortion. I placed a sample
of this at:
http://roonabeck.bellsofireland.com/file67.mpg
I haven't tried to reproduce this again, but thought I'd mention it. I'm
really just interested in trying to get to the bottom of the tinny audio
problem, unless this other distortion also becomes a recurring problem.
Please let me know what I can do to help narrow down the problem.
Thanks,
Noah
_______________________________________________
ivtv-devel mailing list
ivtv-devel@ivtvdriver.org
http://ivtvdriver.org/mailman/listinfo/ivtv-devel