ivtv supercritical tuning?
- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: SELECT data, created, headers, expire, serialized FROM cache_filter WHERE cid = '1:abe614ba8fd0f229dbe74eeadf067312' in /var/www/mythdora/html/includes/cache.inc on line 26.
- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: UPDATE cache_filter SET data = '<p>Hi all,</p>\n<p>this weekend I went from 2.31 to 4.0. Mostly because after a string of power outages and needed fs checks, the system was very unstable. </p>\n<p>And now the channels are very critical in tuning. Using the exact frequency from my old install, many (all) channels flicker, as if it has problems seeing sync pulses, or rather, as if it sees double sync pulses.</p>\n<p>I have to tune most channels to down by 500~1000 khz, to almost the point where it looses color, for it to be stable. As if I have to dampen the signal...</p>\n<p>This is a ivtv question of course, but I was wondering: Anyone else seen anything similar? Supercritical channel tuning?</p>\n<p>BTW: I reinstalled completely, and afterward manually inserted the channel frequencies (and recordings) into MySQL. Old version 2.32 with ivtv-0.7-113 new version 4.0 with ivtv 0.10.1. Two PAL PVR-150 on ASUS Pundit-R</p>\n<p>Thanks</p>\n', created = 1368938260, expire = 1369024660, headers = '', serialized = 0 WHERE cid = '1:abe614ba8fd0f229dbe74eeadf067312' in /var/www/mythdora/html/includes/cache.inc on line 109.
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- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: UPDATE cache_filter SET data = '<p>Just to add in case it may help someone else: </p>\n<p>It seems indeed something did change round about 0.8 of ivtv. A debate was going on whether to turn off or on an internal amp called LNA on the tuner and a lot of people were helped by it, a lot of others got results like mine:</p>\n<p>Read this: <a href=\"http://www.gossamer-threads.com/lists/ivtv/users/32345?search_string=signal%20strength;#32345\" class=\"bb-url\">ivtv-users threat</a></p>\n<p>I\'ll play with my signal strength, read my kernel sources, etc later. Maybe I can tweak the LNA back off.</p>\n', created = 1368938260, expire = 1369024660, headers = '', serialized = 0 WHERE cid = '1:fe9ce1a1c8959aca8657030609b33eca' in /var/www/mythdora/html/includes/cache.inc on line 109.
- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: SELECT data, created, headers, expire, serialized FROM cache_filter WHERE cid = '1:63932c1973d777ea7ab9f437e8360985' in /var/www/mythdora/html/includes/cache.inc on line 26.
- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: UPDATE cache_filter SET data = '<p>There has been a fair amount of chatter about the newer Samsung tuners having a narrow dynamic range - overly sensitive to either too much or too little signal. Too little signal generally shows up as snow, while too much signal usually shows up as overly contrasty or wobbley images or images containing crossmodulation noise from adjacent channels. If your problem is not weak, snowy images, I\'d try simply adding an additional passive splitter in the coax before the tuner input just to get a handle on whether that improves the situation before investing a lot of time looking at the code. I don\'t know the situation where you are but splitters are cheap and plentiful in the US. If the splitter does help, then the effort to get the LNA turned off should be pursued.</p>\n<p>Obviously, the converse is also true. If the splitter kills the signal, you need the LNA turned on.</p>\n<p>Of course this all assumes that the PVR-150s have an LNA and that may not be the case. All the discussion I\'ve seen about the LNA pertained to the PVR-500 which is two PVR-150s on one card fed through a single input with an on card splitter. Since each tuner on a PVR-500 receives half the signal normally received by a PVR-150, it would make sense for Hauppauge to add an LNA to make up for the internal splitters signal loss.</p>\n<p>Two other possibilities that could account for your problem...<br />\nThe power outages damaged a distribution amplifier from which you\'re getting your signal. Connecting the cable directly to a tv tuner should reveal that.<br />\nThe newer ivtv code may be detecting your PVR-150\'s tuner type incorrectly and is substituting a tuner similar to, but not identical with, the tuners your cards actually have. That\'s been a long-standing problem with ivtv and Hauppauge. Unfortunately, the only way I can think of to get a handle on that is to compare dmesg outputs between the old and new setups.</p>\n', created = 1368938260, expire = 1369024660, headers = '', serialized = 0 WHERE cid = '1:63932c1973d777ea7ab9f437e8360985' in /var/www/mythdora/html/includes/cache.inc on line 109.
- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: SELECT data, created, headers, expire, serialized FROM cache_filter WHERE cid = '1:0e1d821836046d4b254658e1d25c2ba7' in /var/www/mythdora/html/includes/cache.inc on line 26.
- user warning: Table './drupal_gding/cache_filter' is marked as crashed and should be repaired query: UPDATE cache_filter SET data = '<p>\n<div class=\"quote-msg\">\n<div class=\"quote-author\"><em>Bigchris</em> wrote:</div>\n<p>..try simply adding an additional passive splitter..</p></div>\n</p><p>Well, that was first on my list (didnt even needed to buy those, have shelves full of junk), and several chained together did add slight noise to the image, but not take away the, by lack of precise term, sync pulse detection problem. Bugger, out goes the LNA theory.</p>\n<div class=\"quote-msg\">\n<div class=\"quote-author\"><em>Bigchris</em> wrote:</div>\n<p>..damaged a distribution amplifier..</p></div>\n<p>No, outages were months ago, system was unstable (booted to kernel panic every so often), but when it worked, picture was perfect.</p>\n\n<div class=\"quote-msg\">\n<div class=\"quote-author\"><em>Bigchris</em> wrote:</div>\n<p>The newer ivtv code may be detecting your PVR-150\'s tuner type incorrectly ... compare dmesg outputs between the old and new setups.</p></div>\n<p>Right. Good theory. But how to get the old dmesg? Reinstall MythDora 2.32? Double bugger. Especially since I am already planning to work business overtime this weekend. Oh well, weekend after that maybe.</p>\n<p>Thanks. However, if anyone else has any alternate, less impacting, ideas, please let me know.</p>\n', created = 1368938260, expire = 1369024660, headers = '', serialized = 0 WHERE cid = '1:0e1d821836046d4b254658e1d25c2ba7' in /var/www/mythdora/html/includes/cache.inc on line 109.
Submitted by cybermaus on September 3, 2007 - 12:20am
Hi all,
this weekend I went from 2.31 to 4.0. Mostly because after a string of power outages and needed fs checks, the system was very unstable.
And now the channels are very critical in tuning. Using the exact frequency from my old install, many (all) channels flicker, as if it has problems seeing sync pulses, or rather, as if it sees double sync pulses.
I have to tune most channels to down by 500~1000 khz, to almost the point where it looses color, for it to be stable. As if I have to dampen the signal...
This is a ivtv question of course, but I was wondering: Anyone else seen anything similar? Supercritical channel tuning?
BTW: I reinstalled completely, and afterward manually inserted the channel frequencies (and recordings) into MySQL. Old version 2.32 with ivtv-0.7-113 new version 4.0 with ivtv 0.10.1. Two PAL PVR-150 on ASUS Pundit-R
Thanks
Just to add in case it may
Just to add in case it may help someone else:
It seems indeed something did change round about 0.8 of ivtv. A debate was going on whether to turn off or on an internal amp called LNA on the tuner and a lot of people were helped by it, a lot of others got results like mine:
Read this: ivtv-users threat
I'll play with my signal strength, read my kernel sources, etc later. Maybe I can tweak the LNA back off.
Just an opinion...
There has been a fair amount of chatter about the newer Samsung tuners having a narrow dynamic range - overly sensitive to either too much or too little signal. Too little signal generally shows up as snow, while too much signal usually shows up as overly contrasty or wobbley images or images containing crossmodulation noise from adjacent channels. If your problem is not weak, snowy images, I'd try simply adding an additional passive splitter in the coax before the tuner input just to get a handle on whether that improves the situation before investing a lot of time looking at the code. I don't know the situation where you are but splitters are cheap and plentiful in the US. If the splitter does help, then the effort to get the LNA turned off should be pursued.
Obviously, the converse is also true. If the splitter kills the signal, you need the LNA turned on.
Of course this all assumes that the PVR-150s have an LNA and that may not be the case. All the discussion I've seen about the LNA pertained to the PVR-500 which is two PVR-150s on one card fed through a single input with an on card splitter. Since each tuner on a PVR-500 receives half the signal normally received by a PVR-150, it would make sense for Hauppauge to add an LNA to make up for the internal splitters signal loss.
Two other possibilities that could account for your problem...
The power outages damaged a distribution amplifier from which you're getting your signal. Connecting the cable directly to a tv tuner should reveal that.
The newer ivtv code may be detecting your PVR-150's tuner type incorrectly and is substituting a tuner similar to, but not identical with, the tuners your cards actually have. That's been a long-standing problem with ivtv and Hauppauge. Unfortunately, the only way I can think of to get a handle on that is to compare dmesg outputs between the old and new setups.
Re: Just an opinion...
..try simply adding an additional passive splitter..
Well, that was first on my list (didnt even needed to buy those, have shelves full of junk), and several chained together did add slight noise to the image, but not take away the, by lack of precise term, sync pulse detection problem. Bugger, out goes the LNA theory.
..damaged a distribution amplifier..
No, outages were months ago, system was unstable (booted to kernel panic every so often), but when it worked, picture was perfect.
The newer ivtv code may be detecting your PVR-150's tuner type incorrectly ... compare dmesg outputs between the old and new setups.
Right. Good theory. But how to get the old dmesg? Reinstall MythDora 2.32? Double bugger. Especially since I am already planning to work business overtime this weekend. Oh well, weekend after that maybe.
Thanks. However, if anyone else has any alternate, less impacting, ideas, please let me know.