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Problem with pauses and audio dropouts - SOLVED
http://forum.linhes.org/viewtopic.php?f=17&t=10950		 Page 1 of 1
Author:  ceenvee703 [ Tue Jul 25, 2006 6:42 pm ]
Post subject:  Problem with pauses and audio dropouts - SOLVED
Recently I've been getting flawed recordings... 2-3 second dropouts in audio, sometimes associated with corrupted video. It clears up usually and the recording proceeds, but the dropouts are becoming more common. Last night's Daily Show recording had at least 3 or 4.

I know it's not a problem with playback as the dropouts appear at the same time in the recording, regardless of the system I play them back on.

This seems to have gotten worse recently and I don't think it's related to anything I've installed.

I've looked at /var/log/mythtv/mythbackend.log and no kinds of errors show up during the recording. (Are there any other logs that might report a problem? I thought mythbackend.log would be the one.)

I'm running R5B7 and using a PVR-250 and a PVR-350 (the HDTV tuner isn't showing the problem AFAIK). Recordings are usually made with "Encoder 1" and from my previous question, I think (but would have to run mythtv-setup to confirm) that Encoder 1 is the 350, and Encoder 2 is the 250. Could the 350 be failing?

I guess I could try reconfiguring the cards so that Encoder 1 is the 250, then see if the problem persists. Guess I could also try upgrading to R5C7.

Thanks for any ideas.
Author:  mjl [ Tue Jul 25, 2006 7:35 pm ]
Post subject: 
Hi,

The R5B7 didn't have the tweak to disable the mythlink.sh housekeeping tools and maybe you are starting to get /myth/tv filled with a bunch of ~64 byte .nuv files.

There is a long thread about the topic back when recordings were .nuv however now the recordings are .mpg and that makes mythlink.sh think they are missing and it generates a "dummy" file so it could be deleted (A series) These will over time, consume space. In R5C7 Cecil modified mythlink.sh, (I think Human may have helped :) )

If this is in fact the cause, it is simple to fix. About 6 of these #

Mike
Author:  ceenvee703 [ Tue Jul 25, 2006 8:45 pm ]
Post subject: 
Thanks mjl for the idea. I found your thread on dummy .nuv files and I did appear to have some, but only from back in Mar/Apr when I was using a different mythlink.sh script. The one I'm using now no longer has that dummy creation part in it, so I didn't have that many.

Nevertheless, I used tjc's script to delete the orphans. I also ran mythtv-setup and swapped cards so that hopefully now the 250 is Encoder 1 and 350 is encoder 2.

Of course, since I changed two variables I won't know which one fixed it, if it is fixed. But if it's fixed I won't care. :)
Author:  mjl [ Tue Jul 25, 2006 9:49 pm ]
Post subject: 
Best of luck!
Mike
Author:  ceenvee703 [ Wed Jul 26, 2006 6:39 am ]
Post subject: 
Well, it didn't matter than I changed two variables, because I'm still seeing the corruption in the recordings. So it definitely wasn't the extra .nuv files.

I'm less definite that the change I made in mythtv-setup actually changed which card is considered Encoder 1 and which Encoder 2. But, I also think that it's not the card... before I made the changes, both the 250 and 350 were recording something last night, and both had at least one instance of the audio dropout and corrupted video. After the changes, the Daily Show recorded and again had a couple of dropped-audio instances.

My next ideas are (a) do the ivtv upgrade as meticulously described by tjc on the wiki and see if that helps, and (b) auto-upgrade to R5C7 and see if that helps.

Thanks in advance for any other ideas on troubleshooting this.
Author:  tjc [ Wed Jul 26, 2006 4:44 pm ]
Post subject: 
If you go to 0.4.6 and see glitches in the capture, try changing the capture resolution in your recording profiles. I find that 640x480 or 720x480 is much cleaner than 480x480.
Author:  mjl [ Wed Jul 26, 2006 8:57 pm ]
Post subject: 
Hi,

Since it only started recently, did you apt-get anything that may have changed some library?

Mike
Author:  ceenvee703 [ Thu Jul 27, 2006 5:51 am ]
Post subject: 
Again, thanks for the suggestions.

The ivtv upgrade went smoothly. The encoder numbers switched so my HD tuner is now Encoder 1, but everything's recording as it should.

Unfortunately, my Daily Show recording from last night (post-ivtv 0.4.6 upgrade) still had a glitch in it. There was only one, so that's good, but it's still not how it used to be.

Almost everything is recorded at the DVD-ready resolution of 352x480 (and anything else gets recorded at 720x480).

Did I apt-get anything recently? Hm, about a month ago I was playing with getting podcasts and vodcasts into my MythVideo directory.

http://mysettopbox.tv/phpBB2/viewtopic.php?t=10584

I tried to get MythStream, podracer, podcatcher, and vodcatcher working, but I don't recall having to apt-get anything to do so. I did edit my sources.list to "stable" as per the wiki and the forums here.

Well, now I'm up-arrowing back through my root commands, and it looks like I did apt-get some things back when I was trying to get those things working... sed and wget and ruby, bittorrent-gui, curl... ugh! Grr! That'll teach me. I guess I'll auto-upgrade and see if that cures things. Thanks again.
Author:  ceenvee703 [ Wed Aug 02, 2006 5:12 am ]
Post subject: 
Problem solved, kind of.

It wasn't MythTV's fault, or KnoppMyth's, or the tuner card, or even something dumb I did.

It's my darling cable company, Comcast!

I started getting suspicious when we were watching live TV (not via MythTV, just the cable right into the TV) and the audio dropped out for a few seconds, just like with my recordings.

So I actually USED MY VCR FOR THE FIRST TIME IN YEARS last night to record Daily Show alongside of MythTV.

This morning I watched the MythTV recording, which glitched at 14 minutes, then had an audio dropout shortly thereafter. Checked the VCR tape... same glitch, same audio dropout. Just to clarify, this is with ANALOG cable TV service, not digital.

So the bad news is that I'll have to see what's going on with Comcast. The good news is that it prompted me to finally upgrade to R5C7.
Author:  tjc [ Wed Aug 02, 2006 4:27 pm ]
Post subject: 
Heh. I hear you. On a semi-regular basis I'll be watching something and have it start pixellating and breaking up, discover that I'm actually watching direct rather than through KM and that it's just a crappy signal from Comcast...
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