[mythtv-users] Razzy/Tinny audio
Daryl McDonald
darylangela at gmail.com
Thu May 22 00:00:40 UTC 2014
On Wed, May 21, 2014 at 7:40 PM, Daryl McDonald <darylangela at gmail.com>wrote:
>
>
> On Fri, May 9, 2014 at 12:41 PM, Daryl McDonald <darylangela at gmail.com>wrote:
>
>> On Fri, May 9, 2014 at 11:47 AM, Stephen Worthington
>> <stephen_agent at jsw.gen.nz> wrote:
>> > On Fri, 9 May 2014 10:48:08 -0400, you wrote:
>> >
>> >>On Fri, May 9, 2014 at 3:29 AM, Stephen Worthington
>> >><stephen_agent at jsw.gen.nz> wrote:
>> >>> On Thu, 8 May 2014 23:59:10 -0400, you wrote:
>> >>>
>> >>>>On Thu, May 8, 2014 at 9:45 PM, Stephen Worthington
>> >>>><stephen_agent at jsw.gen.nz> wrote:
>> >>>>> On Thu, 8 May 2014 12:44:23 -0400, you wrote:
>> >>>>>
>> >>>>>>Greetings Mythizens, as the subject implies I'm looking into
>> >>>>>>distortion from recordings on my analog card.
>> >>>>>>"http://www.mythtv.org/wiki/Hauppauge_PVR-150" this wiki suggests
>> >>>>>>adding a line to my change-channel.sh, like so: "sleep 5; v4l2-ctl
>> >>>>>>--set-audio-input 1 -d /dev/video0 > /dev/null 2>&1" . Before
>> >>>>>>implementing this solution, I'd like to confirm that since my UDEV
>> >>>>>>rule names the card "/dev/videoPVR150" then the added line of script
>> >>>>>>should reflect this change thusly? "sleep 5; v4l2-ctl
>> >>>>>>--set-audio-input 1 -d /dev/videoPVR150 > /dev/null 2>&1" . Should
>> >>>>>>anything else be changed? The digital cards sound good and the
>> analog
>> >>>>>>card has sounded good before, which is why I'm going for this idea
>> >>>>>>first. TIA, Daryl
>> >>>>>
>> >>>>> This problem seems to be caused by mixing of audio from other
>> sources
>> >>>>> on the card. I have this problem with my PVR-500 (dual PVR-150).
>> It
>> >>>>> happens randomly at the start of using the card for a recording,
>> and I
>> >>>>> have never been sure what the cause was, but the drivers have never
>> >>>>> been patched to fix it. The fix you found does work, but what you
>> >>>>> need to do depends on what you are using your PVR-150 for. If you
>> are
>> >>>>> using it to tune to an analogue TV channel, then that fix is the
>> right
>> >>>>> one. If, like me, you are using its S-Video or composite video
>> inputs
>> >>>>> to interface to an STB, then the fix is more complex. In the latter
>> >>>>> case, you also need a command (v4l2-ctl -f <freq>) to tune the TV
>> >>>>> receiver to a frequency that is currently not in use by a signal it
>> >>>>> can receive. This is to ensure that the TV audio does not get mixed
>> >>>>> into the S-Video connection's audio.
>> >>>>>
>> >>>>> This is what I have in my ivtv_audio_fix.sh file that I run from my
>> >>>>> channel change script:
>> >>>>>
>> >>>>> #!/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$device --set-audio-input=0
>> >>>>>
>> >>>>> # Next, also set the tuner frequency. This also seems to be
>> necessary
>> >>>>> # since Mythbuntu 12.04 to suppress a slightly different audio
>> >>>>> distortion.
>> >>>>> # The frequency should be for an unused part of the spectrum, as the
>> >>>>> unwanted
>> >>>>> # audio is coming from whatever the TV tuner is tuned to.
>> >>>>> v4l2-ctl -d$device -f 420
>> >>>>>
>> >>>>> # Reset the audio input to source 1 (the wanted input).
>> >>>>> v4l2-ctl -d$device --set-audio-input=1
>> >>>>>
>> >>>>>
>> >>>>> And this is my channel change script (change-channel-skynz.sh):
>> >>>>>
>> >>>>> #!/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 &
>> >>>>> _______________________________________________
>> >>>>> mythtv-users mailing list
>> >>>>> mythtv-users at mythtv.org
>> >>>>> http://www.mythtv.org/mailman/listinfo/mythtv-users
>> >>>>> http://wiki.mythtv.org/Mailing_List_etiquette
>> >>>>> MythTV Forums: https://forum.mythtv.org
>> >>>>
>> >>>>Thanks Stephen, I use my PVR 150 to record from an analog STB
>> >>>>connected via RCA jacks, this card has apparently has five possible
>> >>>>input connections, one "tuner" via coax and two each of "component"
>> >>>>and "S-video". To leave my system connected as is, I would need to
>> >>>>create a new " ivtv_audio_fix.sh" file like yours, but change the name
>> >>>>of the tuner card appropriately and modify my "change-channel.sh" as
>> >>>>outlined in the original post? Or, maybe more simply, change the input
>> >>>>connection to "tuner" over coax and add the one line to my
>> >>>>"change-channel.sh"? with the first solution, I must need one more
>> >>>>line in the "change-channel.sh" to call the new "ivtv_audio_fix.sh"
>> >>>>script, right? But I'm not sure where to put it.
>> >>>>Daryl
>> >>>
>> >>> Create the ivtv_audio_fix.sh file (I have mine in /usr/local/bin where
>> >>> my change-channel-skynz.sh script is). Then if your existing channel
>> >>> change script works at all like mine, you can just add these two lines
>> >>> at the end of it:
>> >>>
>> >>> # Workaround for bug which causes audio distortion on some recordings.
>> >>> /usr/local/bin/ivtv_audio_fix.sh /dev/videoPVR150 &
>> >>>
>> >>> What that does is to run the ivtv_audio_fix.sh script as a separate
>> >>> independent job (that is what & does). The channel change script can
>> >>> finish and that lets MythTV know that the channel change has been
>> >>> done. The ivtv_audio_fix.sh script will do its sleep while MythTV
>> >>> records for the sleep time (you will hear the tinny sound for the
>> >>> first few seconds of the recording, if it happened for that
>> >>> recording), then the script will wake up and do its fix. The fix has
>> >>> to be done after all the recording startup work that MythTV does - if
>> >>> it is done too early it does not work as the v4l commands sent by
>> >>> MythTV override it. When the ivtv_audio_fix.sh script has done its
>> >>> v4l commands it will just stop without reporting back to the script
>> >>> that called it (which finished several seconds before).
>> >
>> >>Hopefully I'm not over-reading this, what I did is create the
>> >>ivtv_audio_fix.sh file in /usr/local/bin, and I changed (near the top)
>> >>"device=/dev/video0" to "devive=/dev/videopvr150" and then added the
>> >>two lines to the end of my "change-channel.sh" exactly as yours is
>> >>(without the /dev/videoPVR150) [my uDev rule uses lower case pvr, my
>> >>bad] . This preceding issue is at the heart of my original question;
>> >>am I correct or wrong in assuming that the new name created by my uDev
>> >>rule should be reflected in the "ivtv_audio_fix.sh" script? Thanks
>> >>again Daryl
>> >
>> > If you exactly copied the two lines I posted to the bottom of your
>> > change-channel.sh, then it will not work, due to the mis-spelling of
>> > /dev/videopvr150 as /dev/videoPVR150 in what I wrote. My
>> > ivtv_audio_fix.sh script accepts one optional parameter on its command
>> > line, the name of the device to control. If that parameter is absent,
>> > it will use the default device setting you changed at the top of
>> > ivtv_audio_fix.sh. It was not necessary to change that as the two
>> > lines I posted had the device name as a parameter. So you either need
>> > to fix the spelling of /dev/videopvr150 on the call to
>> > ivtv_audio_fix.sh in change-channel.sh, or remove the /dev/videoPVR150
>> > from there and let ivtv_audio_fix.sh use its default device name that
>> > you have already fixed.
>> > _______________________________________________
>> > mythtv-users mailing list
>> > mythtv-users at mythtv.org
>> > http://www.mythtv.org/mailman/listinfo/mythtv-users
>> > http://wiki.mythtv.org/Mailing_List_etiquette
>> > MythTV Forums: https://forum.mythtv.org
>>
>> What I exactly copied into my change-channel.sh was the last two lines
>> of your change_channel_skynz.sh, so I think I'm good with the audio
>> fix script edited to reflect the uDev name of my analog card and my
>> channel script calling the fix script just like yours does, not the
>> way you suggested had I not edited.
>>
>> The University of Toronto is offering free online computer science
>> courses this fall, after applying myself in this direction I hope to
>> get a much better practical understanding of all the things that I've
>> received excellent coaching on from this list. Thanks Stephen, thanks
>> list, enormous thanks Devs, I love Mythtv. (BE & FE) Daryl
>>
>
> I've had almost two weeks of clear audio recordings, but a recording
> yesterday has the Tin/Raz effect. Below are my "change-channel.sh" and
> "ivtv_audio_fix.sh"
>
> REMOTE_NAME=DCT700
> cmd="$1"
> lirc_socket="/var/run/lirc/lircdSerial"
>
> /usr/local/bin/check_stb 1>/dev/null 2>/dev/null || :
> sleep 2
>
> case $cmd in
> [0-9]*)
> for digit in $(echo $1 | sed -e 's/./& /g'); do
> #irsend -d /dev/lircd SEND_ONCE $REMOTE_NAME $digit
> irsend -d ${lirc_socket} SEND_ONCE $REMOTE_NAME $digit
> sleep 0.2
> # If things work OK with sleep 1, try this for faster channel
> changes:
> # sleep 0.3
> done
> #irsend -d /dev/lircd SEND_ONCE $REMOTE_NAME OK
> irsend -d ${lirc_socket} SEND_ONCE $REMOTE_NAME OK
> sleep 1
> #irsend -d /dev/lircd SEND_ONCE $REMOTE_NAME EXIT
> irsend -d ${lirc_socket} SEND_ONCE $REMOTE_NAME EXIT
> ;;
>
> *)
> #irsend SEND_ONCE $REMOTE_NAME $cmd
> irsend -d ${lirc_socket} SEND_ONCE $REMOTE_NAME $cmd
> ;;
> esac
>
>
> # Workaround for bug which causes audio distortion on some recordings.
> /usr/local/bin/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/videopvr150
> 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$device --set-audio-input=0
>
> # Next, also set the tuner frequency. This also seems to be necessary
> # since Mythbuntu 12.04 to suppress a slightly different audio distortion.
> # The frequency should be for an unused part of the spectrum, as the
> unwanted
> # audio is coming from whatever the TV tuner is tuned to.
> v4l2-ctl -d$device -f 420
>
> # Reset the audio input to source 1 (the wanted input).
> v4l2-ctl -d$device --set-audio-input=1
>
>
> --------------------------------------------------------------------------------------------
>
> I thought I'd followed Mr Worthington's advice to the letter, maybe not ,
> or maybe I need to pursue a different angle. If anyone can critique this
> solution, or point me in a new direction, I'd appreciate it.
>
> TIA Daryl
>
I think I just answered my own question. further investigation revealed
that I hadn't "chmod 775" ed, my "Ivtv_audio_fix.sh" After tomorrow's
recording I should be able to report positive results, apologies for
troubling unnecessarily. Daryl
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