HDHR + Mythtv -> crashes on some channels

[anonymous]

I'm using a HDHomerun, and when I tune to some channels, it seems that frequently mythtv dies (the channels work on VLC). From my reading of the logs everything looks like it is working fine, then the "previewer" has a problem with the file, recording seems to stop. From the output of the front end it complains about the ringbuf not opening. I have attached the verbose frontend/backend logs. It's not isolated to HD channels because I can get PBS fine, and the other night it worked for ABC and now won't. I'm wondering if it's a problem decoding the stream, or the previewer starts to soon and causes a quit. I can do a stream capture from hdhomerun_config if needed. I'm using quick tuning so it has pid filtering, but that doesn't seem to make a difference. Using the latest svn (r13424) version of mythtv (from this morning). Ubuntu feisty.

James

[DannyCan@…]

I might be having this same problem. I am running ubuntu-server 7.04 for my backend using a HDHomeRun also. I will post my backend log ending to show the crash.

[DannyCan@…]

My Mythbackend log before crash

[peabody124@…]

I think I've solved this. Turns out with upgrading and downgrading my mythtv setup the dtv_multiplex table got out of sync with the channel table so the frequencies didn't align with the real ones. I manually remapped them (if you can work with sql) but if not you can delete your myth database and rescan for channels.

However, it would be nice if when mythbackend tunes to a channel and gets nonsense it didn't cause the frontend to drop out of mythtv (or stall so long) - and definitely give a nicer error. It was pretty confusing since it would show signal strength at 95% normally and then just die.

[anonymous]

Replying to peabody124@gmail.com:

I think I've solved this. Turns out with upgrading and downgrading my mythtv setup the dtv_multiplex table got out of sync with the channel table so the frequencies didn't align with the real ones. I manually remapped them (if you can work with sql) but if not you can delete your myth database and rescan for channels.

However, it would be nice if when mythbackend tunes to a channel and gets nonsense it didn't cause the frontend to drop out of mythtv (or stall so long) - and definitely give a nicer error. It was pretty confusing since it would show signal strength at 95% normally and then just die.

Is there a mysql command I can use to check if we have this problem of yours?

[danielk]

There is already a ticket for making the backend not crash when ffmpeg crashes during preview generation #3361.

But this ticket is only invalid because there is no proper backtrace. See the TicketHowTo on what to do when reporting a SEGFAULT. Also if the crash is in ffmpeg we request that you test the latest ffmpeg and report the problem to that project if the problem exists there, and tell us if it doesn't.

[peabody124@…]

It didn't make the frontend crash with a seg fault - probably poor choice of words. It dropped back to the frontend with an error. But it seems like if you are watching tv and tune to a channel that doesn't work (or say a sub channel that isn't running right now) then there should be a message in the livetv section "Warning: could not access channel" and allow you to retune. This also applies to things like music channels which you see fine and are valid streams, but mythfrontend can't work with right now. It also would make initially sorting your channels tons easier if you could try locking on streams and if they were encrypted then it just says "encrypted channel". Anyway, I defer to the dev's whether to reopen this.

So I connected to my sql database and said

select channum,freqid,mplexid from channel where sourceid=1;

to display the channel mapping to mplexid and

select mplexid,frequency from dtv_multiplex;

and then saw those mappings didn't align to the scan i did with hdhomerun_config or the tables I'd seen online.

This command might be easier: select channel.freqid,dtv_multiplex.frequency FROM channel,dtv_multiplex WHERE channel.mplexid = dtv_multiplex.mplexid ORDER BY channel.freqid;

[DannyCan@…]

Replying to peabody124@gmail.com:

It didn't make the frontend crash with a seg fault - probably poor choice of words. It dropped back to the frontend with an error. But it seems like if you are watching tv and tune to a channel that doesn't work (or say a sub channel that isn't running right now) then there should be a message in the livetv section "Warning: could not access channel" and allow you to retune. This also applies to things like music channels which you see fine and are valid streams, but mythfrontend can't work with right now. It also would make initially sorting your channels tons easier if you could try locking on streams and if they were encrypted then it just says "encrypted channel". Anyway, I defer to the dev's whether to reopen this.

So I connected to my sql database and said

select channum,freqid,mplexid from channel where sourceid=1;

to display the channel mapping to mplexid and

select mplexid,frequency from dtv_multiplex;

and then saw those mappings didn't align to the scan i did with hdhomerun_config or the tables I'd seen online.

This command might be easier: select channel.freqid,dtv_multiplex.frequency FROM channel,dtv_multiplex WHERE channel.mplexid = dtv_multiplex.mplexid ORDER BY channel.freqid;

I am attaching the output of the three commands, I am not sure if this means it is correct or not...

[DannyCan@…]

I am not sure if my mythbackend crashes are related to preview generation.
The error that occurs is a "MythSocket?(a9d60598:-1): writeStringList: Error, socket went unconnected." error.
It happened again with more of the errors so maybe the log from that will clarify it better.
*see attachment*

[DannyCan@…]

Another mythbackend log with more errors.