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Fix PAL jitter
http://forums.linhes.org/viewtopic.php?f=3&t=755		 Page 1 of 1
Author:  pete-edworthy [ Wed Feb 18, 2004 1:09 pm ]
Post subject:  Fix PAL jitter
My image jumped up and down on both playback and live tv.
The problem turned out to be the capture resolution.

The vertical resolution needs to be 576, not 480 that it is for NTSC.

bye
Pete
Author:  haan [ Sat Feb 28, 2004 5:30 pm ]
Post subject:  What setting?
I have a similar problem using a PVR350 (TV in only) in Sweden (PAL-B). My screen is jumping upp and down. I also have a smal grey, black and white line blinking at the same speed on the top of the picture.
In what way can you alter the "capture resolution"?

regards
håkan
Author:  pete-edworthy [ Sun Feb 29, 2004 6:24 am ]
Post subject:  Where to change settings
Hi,

I change the following settings:

PVR 250
--setting ivtv for non us

su
[password]
#find the tunner type
modprobe tveeprom
tail /var/log/syslog
#this will have a line with tuner=........type=x

#edit /etc/mythtv/modules/ivtv
#set the tuner to the type from ivtv out
#set debug to 0 if you have a slow hd or processor
cat <<EOF > /etc/mythtv/modules/ivtv
alias char-major-81 videodev
alias char-major-61 lirc_i2c
options ivtv debug=0 ivtv=pal
options tuner type=whatever the tuner number was
options msp3400 once=1 simple=1
add below ivtv msp3400 saa7115 tuner
add above ivtv lirc_dev lirc_i2c
EOF

cat <<EOF > /etc/sysconfig/ivtv/cfg-0
IVTV_TUNER=tuner type #1 for uk
IVTV_TYPE=PAL
EOF

reboot

I also set the capture resolutions, i.e. live tv etc to 640, 578
Author:  willem [ Sun Feb 29, 2004 10:28 am ]
Post subject: 
The screen jumping up and down may have to do with the capture resolution in your recording profiles. The vertical number is probably set to 480 (the default NTSC) changing this to 576 (PAL) should do the trick.
Author:  haan [ Sun Feb 29, 2004 2:51 pm ]
Post subject: 
Thanks for the reply! I have never seen any references to "/etc/sysconfig/ivtv/cfg-0" before, so it was set to NTSC, however changing it to PAL didn’t make any difference. The screen was still jumping.
Just to make sure we're talking about the same thing, the picture is just moving up and down a little bit, about one or two pixel lines every second. Watching normal TV is quite all right, but not as good as ordinary TV. The grey/whit line appearing at the top of the screen is more annoying. I think it is this line that makes the screen move.

I've been using both the TV out of the PVR350 and a Nvidia GF MX440 and I got the same problem with both setups.

This is my IVTV modules file:
Code:
root@tevis:/home/haan5# cat /etc/mythtv/modules/ivtv
alias char-major-81 videodev
alias char-major-81-0 ivtv
alias char-major-61 lirc_i2c
options ivtv ivtv_debug=1 ivtv_pal=1 tuner=20
options tuner type=20 pal=i
options msp3400 once=1 simple=1
options saa7127 enable_output=1 output_select=1 pal=1
add below ivtv msp3400 saa7115 saa7127 tuner
add above ivtv lirc_dev lirc_i2c ivtv-fb
post-install ivtv /usr/local/bin/test_ioctl -d /dev/video0 -u 0xff
post-install ivtv /usr/local/bin/test_ioctl -d /dev/video16 -u 0xff
post-install ivtv /usr/local/bin/test_ioctl -d /dev/video32 -u 0xff
post-install ivtv /usr/local/bin/test_ioctl -d /dev/video224 -u 0xff
post-install ivtv /usr/local/bin/test_ioctl -y mute=0
# 0xff for PAL #
Author:  pete-edworthy [ Wed Mar 03, 2004 7:49 am ]
Post subject:  Ideas
Hi,

When the encode resolution, in the live tv etc settings is on 480 height the jump is quite large more like 5 lines. Yours sounds as through the tunner is passing through aditional info such as a stereo sound channel or a teletext channel that causes the gray at the top. Have you tried changing the setup to:

Code:
options tuner type=20 pal=b


My understanding of the different version of pal is that each has different extra info added, i.e. i has teletext, g has a stereo sound channel added.

so this may solve it. Also do you have the deinterlace options on and the anti jitter?

good luck,
Pete
Author:  saruman [ Wed Mar 03, 2004 9:46 am ]
Post subject: 
If I am not mistaken, the file /etc/init.d/set_ivtv_params is not correct.

Looking through it the other (as I was wrestling with TVOUT issues), I realized it doesn't set the parameters to PAL resolution, even if PAL is specified in /etc/sysconfig/cfg-0.

Basically, the line:
Code:
$IVTVCTL -d /dev/video$f -f width=720,height=480

was hardcoding the display parameters.

So, I have modified it to read as below. Does everybody concur?
Cesman, want to merge this into the next release?

Laurent
----------------------------------------------------
Code:
#!/bin/bash
#       Set the ivtv Parameters
########################################################################
IVTVCTL='test_ioctl'
IVTVDIR='/etc/sysconfig/ivtv'
#----------------------------------------------------------------------#
# Default values, if not specified in $IVTVDIR/cfg-*
IVTV_DT='0'             # Tuner input,
IVTV_DF='PAL'           # tuner format [NTSC|PAL]
########################################################################
[ -d "$IVTVDIR" ] || exit 1

PATH="$PATH:/usr/local/bin"
# See how we were called:
case $1 in
    (start)
        cd $IVTVDIR || exit 2
        for g in $(echo cfg-*) ; do
            f=${g#cfg-}
            unset IVTV_TUNER IVTV_RATE IVTV_PEAK IVTV_TYPE
            source cfg-$f
            case $IVTV_TYPE in
                ("")    IVTV_TYPE=0x3000
                        IVTV_HEIGHT=480
                        IVTV_WIDTH=720
                        ;;
                (NTSC)
                        IVTV_TYPE=0x3000
                        IVTV_HEIGHT=480
                        IVTV_WIDTH=720
                        ;;
                (PAL)
                        IVTV_TYPE=0xff
                        IVTV_HEIGHT=576
                        IVTV_WIDTH=720
                        ;;
            esac
            $IVTVCTL -d /dev/video$f -u $IVTV_TYPE
            $IVTVCTL -d /dev/video$f -p ${IVTV_TUNER:-${IVTV_DT}}
            $IVTVCTL -d /dev/video$f -f width=$IVTV_WIDTH,height=$IVTV_HEIGHT
            $IVTVCTL -d /dev/video$f -c dnr_mode=0,dnr_temporal=0
        done
        ;;
    (stop) # don't do anything on stop.
        ;;
    *)
        echo "Usage: /etc/init.d/set_ivtv_params {start|stop}"
        exit 1
        ;;
esac
########################################################################
# End
Author:  haan [ Wed Mar 03, 2004 3:41 pm ]
Post subject:  Tried those things!
Thanks Pete and Sauroman (scary name!) for your input. I checked both of your ideas.

Pete, changing the type to "b" is of course correct. But I'm not sure if it did anything to my picture quality. I still got this line on top of my screen. I also tried to change vbi to "none" in the general setup.

Sauroman, I edited the file you mentioned and changed the hard coded value to "576". I'm not sure if it did any difference.

After rejecting the idea to mask the TV screen with black tape I changed to 5% overscan in the "myth TV playback" settings. I tried overscan before but then I edited XF86Config-4 and that really messed up TV quality. This worked really well.

Adding overscan made the most difference. The overscan is hiding the line and the picture quality is really nice! I think I'll stick with setting for now on.

Thanks both of you for your input.
håkan
Author:  finster [ Sun May 09, 2004 4:00 pm ]
Post subject: 
I have found this thread http://www.gossamer-threads.com/lists/mythtv/users/43641 which seems to have fixed the "jitter" on my system.

Seems to be an issue in PAL countries - the default capture settings within MythTV itself need adjusting to cater for the different resolution.

HTH.

Andy.
Author:  haan [ Mon May 10, 2004 12:56 am ]
Post subject:  Yes - that solves the problem
I found that setting a while ago and all my jitter problems went away!

Thanks for the reply!
håkan
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