[mythtv-users] Everything works on my rebuilt DVR except the tuner cards. Help?

Karl Newman newmank1 at asme.org
Thu Oct 17 15:51:20 UTC 2013


On Wed, Oct 16, 2013 at 10:48 PM, Stephen Worthington <
stephen_agent at jsw.gen.nz> wrote:

> On Wed, 16 Oct 2013 21:35:25 -0700, you wrote:
>
> >On Wed, Oct 16, 2013 at 6:23 PM, Stephen Worthington <
> >stephen_agent at jsw.gen.nz> wrote:
> >
> >> On Wed, 16 Oct 2013 14:45:12 -0700, you wrote:
> >>
> >> >On Wed, Oct 16, 2013 at 12:46 PM, Rajil Saraswat <rajil.s at gmail.com>
> >> wrote:
> >> >
> >> >> >> Yes, your deduction is correct. The main card works fine in
> 3.10.7,
> >> it
> >> >> is
> >> >> >> only the daughter card which is broken.
> >> >> >
> >> >> > Have you done a git bisect to determine which commit caused the
> >> breakage?
> >> >> > That would be helpful to the developers, I'm sure, so they could
> find
> >> the
> >> >> > cause more easily.
> >> >> >
> >> >> > Karl
> >> >> >
> >> >>
> >> >> The results of the git bisect are here
> >> >> http://www.spinics.net/lists/linux-media/msg68963.html
> >> >>
> >> >> wm8775 seems to be the culprit.
> >> >>
> >> >
> >> >Glad you found it. Thanks for taking that time. Now I hope they can fix
> >> it.
> >> >Maybe the fix will also solve the occasional problem I have with minor
> >> >audio distortion on my PVR-500 using the on-bracket composite input (it
> >> >sounds tinny and slightly scratchy).
> >> >
> >> >Thanks,
> >> >
> >> >Karl
> >>
> >> Your PVR-500 audio problem is likely the same as mine - the drivers
> >> seem to have a bug that causes audio to be mixed in from other inputs.
> >> I have a script that works around the problem, both for recording FM
> >> radio for my mother with her PVR-150 and for me recording S-Video from
> >> my STB with my PVR-500.
> >>
> >> This is the fix script for recording S-Video from my PVR-500
> >> (ivtv_audio_fix.sh):
> >>
> >> #!/bin/sh
> >>
> >> # Workaround for bug which causes audio distortion on some recordings.
> >> # From http://urlgrey.net/?p=231
> >>
> >> sleep 3
> >>
> >> if [ $# -eq 0 ]; then
> >>     device=/dev/video0
> >> else
> >>     device=$1
> >> fi
> >>
> >> # First, set the audio input in turn to each of the unwanted audio
> >> inputs.
> >> # This only became necessary as of Mythbuntu 12.04.
> >> v4l2-ctl -d$device --set-audio-input=2
> >> v4l2-ctl -d$device --set-audio-input=0
> >>
> >> # Next, also set the tuner frequency.  This also seems to be necessary
> >> # since Mythbuntu 12.04 to suppress a slightly different audio
> >> distortion.
> >> # The frequency should be for an unused part of the spectrum, as the
> >> unwanted
> >> # audio is coming from whatever the TV tuner is tuned to.
> >> v4l2-ctl -f 420
> >>
> >> # Reset the audio input to source 1 (the wanted input).
> >> v4l2-ctl -d$device --set-audio-input=1
> >>
> >>
> >> And this fixed FM recording from my mother's PVR-150:
> >>
> >> #!/bin/sh
> >>
> >> # Workaround for bug which causes audio distortion on some recordings.
> >> # From http://urlgrey.net/?p=231
> >>
> >> sleep 3
> >>
> >> if [ $# -eq 0 ]; then
> >>     device=/dev/video0
> >> else
> >>     device=$1
> >> fi
> >>
> >> # First, set the audio input in turn to each of the unwanted audio
> >> inputs.
> >> # This only became necessary as of Mythbuntu 12.04.
> >> v4l2-ctl -d$device --set-audio-input=2
> >> v4l2-ctl -d$device --set-audio-input=0
> >>
> >> # Next, also set the tuner frequency.  This also seems to be necessary
> >> # since Mythbuntu 12.04 to suppress a slightly different audio
> >> distortion.
> >> # The frequency should be for an unused part of the spectrum, as the
> >> unwanted
> >> # audio is coming from whatever the TV tuner is tuned to.
> >> # DO NOT DO THIS FOR RADIO RECORDINGS
> >> #v4l2-ctl -f 420
> >>
> >> # Reset the audio input to source 1 (the wanted input).
> >> v4l2-ctl -d$device --set-audio-input=1
> >>
> >> The fix script should be called from the channel change script.  Use &
> >> to make it run in parallel with the channel change script, after the
> >> channel has been changed.  Here is my channel change script for using
> >> my PVR-500 with my STB:
> >>
> >> #!/bin/sh
> >>
> >> REMOTE_NAME=Pace_RC-30
> >> cmd="$1"
> >>
> >> # If things work OK with sleep 1, try this for faster channel changes:
> >> # sleep 0.3
> >> sleep_amt=1.0
> >>
> >> # See if this helps with missing digits at the start of a channel
> >> change.
> >> sleep 1.0
> >>
> >> #echo Change channel: $cmd >>/tmp/irsend.txt
> >>
> >> case $cmd in
> >>     [0-9]*)
> >>     # make sure we unmute by hitting vol up
> >>     #/usr/bin/irsend SEND_ONCE $REMOTE_NAME Vol+
> >>     #sleep $sleep_amt
> >>     for digit in $(echo $1 | sed -e 's/./& /g'); do
> >>             #echo irsend SEND_ONCE $REMOTE_NAME $digit
> >> >>/tmp/irsend.txt
> >>         /usr/bin/irsend SEND_ONCE $REMOTE_NAME $digit
> >>         sleep $sleep_amt
> >>     done
> >>     ;;
> >>
> >>     *)
> >>         /usr/bin/irsend SEND_ONCE $REMOTE_NAME $cmd
> >>         ;;
> >> esac
> >>
> >>
> >> # Workaround for bug which causes audio distortion on some recordings.
> >> /usr/local/bin/ivtv_audio_fix.sh $video &
> >>
> >
> >Interesting. Thanks for the script; I'll try it out. Do you know if this
> >bug has been reported upstream?
>
> I have not reported it, or even tried to find a report.  I would not
> know where to look, actually.
>
>
I found this 5 year old thread (!!) which seems to be the same symptoms:
http://www.mail-archive.com/ivtv-users@ivtvdriver.org/msg08058.html It's a
long thread and I haven't read through it completely yet, but obviously
whatever fix there was (if any) didn't make it into the main codebase, at
least not in the default configuration. If I find anything interesting
after reading through the whole thing, I'll let you know.


> >One question--You are passing $video to the
> >ivtv_audio_fix.sh script, but I where does it get set in the channel
> change
> >script?
>
> Looks like I did not test that - $video is not set and will be
> defaulting to empty, so ivtv_audio_fix.sh will be defaulting to
> /dev/video0.  So no harm done, but it is a bug.  It was quite a while
> ago that I did this, but I think it will be a cut & paste bug - I will
> have copied that line from another script I was using for testing.
>
>
Okay, thanks. I don't know if Myth can pass the input used to the channel
change script (seems unlikely), but I have the problem on only one input (I
believe) so I'll just put it in the channel change script for that
particular cable box.

Thanks,

Karl
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.mythtv.org/pipermail/mythtv-users/attachments/20131017/732cc5ec/attachment.html>


More information about the mythtv-users mailing list