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

Stephen Worthington stephen_agent at jsw.gen.nz
Thu Oct 17 05:48:41 UTC 2013


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.

>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.

>Karl


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