[mythtv-users] Crash on "use video as timebase"

[hpoley at dds.nl]

Replying to myself....

Citeren Henk Poley <hpoley at dds.nl>:

> I updated to 0.14 (gentoo ebuilds) to use this option (display video at
> static rate and scale audio), to see if it fixes my wierd buffer underruns
> (the dreaded "prebuffering audio data"). But this option crashes MythTV :-(
> 
> I have been able to watch something, but it either freezes the screen
> quickly, or when you change channels it will freeze. Alt+F4 will stop the
> graphical part of mythfrontend, but I will still need to kill the other
> mythfrontend thread.

If I run mythfrontend (-v playback) from a console I can Ctrl+C to stop the 
frontend entierly.

I investigated it a bit more, and I think it is because it tries to synchronise 
the video to vsync. At the moment you Alt+Tab out of the fullscreen MythTV it 
can't see this vscync anymore (even though the video is still visible behind my 
console window). When this happens mythfrontend outputs lots of "waiting for 
free video buffers timed out" lines, see log below. It might be better if it 
switched dynamicly between vsync and any of the other synchronisation strategies 
(using RTC clock, etc.)

Why changeing channels has the same behaviour is beyond me, but well this is 
what I think is happening.

> I use a Cinergy 600 (saa7134 based) with the internal OSS device, so I need
> to grab audio at 32000Hz. This might be related, but "shouldn't".
>
> Anybody knows a fix?

Well, still open for suggestions

   Henk Poley <><

----
Log:

bash-2.05b$ mythfrontend -v playback
2004-02-06 10:03:30 mythfrontend version: 0.14.20040123-1 www.mythtv.org
2004-02-06 10:03:30 Enabled verbose msgs : important general playback
2004-02-06 10:03:30 Registering Internal as a media playback plugin.
2004-02-06 10:03:30 Registering MythMusic Media Handler as a media handler
The QSocket connector in lcddevice could not connect to an LCDd...
Why? The connection was refused.
2004-02-06 10:03:33 Connecting to backend server: 192.168.2.101:6543 (try 1 of 
5)
2004-02-06 10:03:33 Using protocol version 1
2004-02-06 10:03:33 Using protocol version 1
2004-02-06 10:03:33 Using protocol version 1
2004-02-06 10:03:33 Estimated bitrate = 0
2004-02-06 10:03:33 Opening OSS audio device '/dev/dsp'.
2004-02-06 10:03:33 Over/underscan. V: 0, H: 0, XOff: 0, YOff: 0
2004-02-06 10:03:33 Using XV port 57
2004-02-06 10:03:34 Changing from None to WatchingLiveTV
2004-02-06 10:03:34 Video timing method: next trigger
2004-02-06 10:03:34 Refresh rate: 17748, frame interval: 40000
2004-02-06 10:03:34 waiting for prebuffer...
'video_output' mean = '41432.84', std. dev. = '3684.97', fps = '24.14'
avsync_avg: 243, warpfactor: 1.04891, warpfactor_avg: 0.999939
'video_output' mean = '41654.35', std. dev. = '4387.85', fps = '24.01'
avsync_avg: -45, warpfactor: 0.997746, warpfactor_avg: 1.00009
'video_output' mean = '41406.07', std. dev. = '3684.15', fps = '24.15'
avsync_avg: -128, warpfactor: 0.974235, warpfactor_avg: 0.999971
'video_output' mean = '41721.46', std. dev. = '3493.09', fps = '23.97'
avsync_avg: -184, warpfactor: 0.962834, warpfactor_avg: 0.999764
'video_output' mean = '41434.12', std. dev. = '2254.92', fps = '24.13'
avsync_avg: -183, warpfactor: 0.962932, warpfactor_avg: 0.999517
waiting for free video buffers timed out
waiting for free video buffers timed out
waiting for free video buffers timed out
waiting for free video buffers timed out

bash-2.05b$