[mythtvnz] Audio stutter on some channels...

Wed Sep 2 11:59:41 BST 2009

Hello

With better aerial reception, I can now see TV1,2,3,6,7 fine and mostly
rock solid.  However, channels TV3+1,C4,Prime,Chinese,Freeview|HD all
have audio stutter on them.  Frontend logs has this:

2009-09-02 22:37:37.836 WriteAudio: buffer underrun
2009-09-02 22:37:38.646 WriteAudio: buffer underrun
2009-09-02 22:37:39.553 WriteAudio: buffer underrun
2009-09-02 22:37:42.062 WriteAudio: buffer underrun
2009-09-02 22:37:42.434 NVP: prebuffering pause
2009-09-02 22:37:42.436 WriteAudio: buffer underrun
2009-09-02 22:37:42.903 WriteAudio: buffer underrun
2009-09-02 22:37:42.985 WriteAudio: buffer underrun
2009-09-02 22:37:43.040 NVP: prebuffering pause
2009-09-02 22:37:43.041 WriteAudio: buffer underrun
2009-09-02 22:37:43.047 NVP: prebuffering pause
2009-09-02 22:37:44.222 WriteAudio: buffer underrun
2009-09-02 22:37:44.436 NVP: prebuffering pause
2009-09-02 22:37:44.438 WriteAudio: buffer underrun
2009-09-02 22:37:44.445 NVP: prebuffering pause
2009-09-02 22:37:46.533 WriteAudio: buffer underrun

Aggressive audio buffer off, and extra audio buffers are checked.
Anywhere else I should be checking for these.

I notice that I cannot get good reception (ie watchable) off the
778000000 multiplex.  Result of DVBtune is as follows:

> [root at goofy dvbtune-0.5]# ./dvbtune -f 778000000 -I 0 -qam 64 -gi 16 -cr 3_4 -bw 8 -tm 8 -m 2
> Using DVB card "DiBcom 3000MC/P"
> tuning DVB-T (in United Kingdom) to 778000000 Hz
> polling....
> Getting frontend event
> FE_STATUS:
> polling....
> Getting frontend event
> FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI FE_HAS_SYNC
> Bit error rate: 0
> Signal strength: 35762
> SNR: 0
> FE_STATUS: FE_HAS_SIGNAL FE_HAS_LOCK FE_HAS_CARRIER FE_HAS_VITERBI FE_HAS_SYNC
> Signal=35763, Verror=0, SNR=0dB, BlockErrors=11, (S|L|C|V|SY|)
> Signal=35795, Verror=0, SNR=0dB, BlockErrors=0, (S|L|C|V|SY|)
> Signal=35737, Verror=0, SNR=0dB, BlockErrors=0, (S|L|C|V|SY|)
> Signal=35773, Verror=0, SNR=0dB, BlockErrors=0, (S|L|C|V|SY|)
> Signal=35800, Verror=0, SNR=0dB, BlockErrors=0, (S|L|C|V|SY|)
> Signal=35775, Verror=0, SNR=0dB, BlockErrors=0, (S|L|C|V|SY|)
> 

and only TV3 off the 706000000 multiplex.  Same result with dvbtune.  That is, I get 0 Verrors and 0 BlockErrors.

My frontend log also is getting alot of these even though I dont get Verror or Block errors on the multiplex, is this still a sign of bad signal input?

> 2009-09-02 22:55:36.336 VideoOutputXv: XVideo Adaptor Name: 'NV17 Video Texture'
> 2009-09-02 22:55:37.371 AFD: Opened codec 0x9ae73f0, id(H264) type(Video)
> 2009-09-02 22:55:37.372 AFD: codec Unknown Codec ID has 2 channels
> 2009-09-02 22:55:37.372 AFD: Opened codec 0x9ae6c50, id(Unknown Codec ID) type(Audio)
> 2009-09-02 22:55:37.373 AFD: Opened codec 0x9afc840, id(DVB_SUBTITLE) type(Subtitle)
> 2009-09-02 22:55:37.379 Opening audio device 'default'. ch 2(2) sr 48000
> 2009-09-02 22:55:37.380 Opening ALSA audio device 'default'.
> ALSA lib control.c:909:(snd_ctl_open_noupdate) Invalid CTL /dev/mixer
> 2009-09-02 22:55:37.408 AudioOutput Warning: Mixer attach error -2: No such file or directory
>                         Check Mixer Name in Setup: '/dev/mixer'
> 2009-09-02 22:55:37.409 NVP: Enabling Audio
> 2009-09-02 22:55:37.425 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> ...
> 2009-09-02 22:55:37.436 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:37.526 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:37.526 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:37.705 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:37.705 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:37.893 NVP: prebuffering pause
> 2009-09-02 22:55:39.103 LiveTV forcing JumpTo 1
> 2009-09-02 22:55:39.134 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> ...
> 2009-09-02 22:55:39.141 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:39.151 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:39.255 NVP: prebuffering pause
> 2009-09-02 22:55:39.539 AFD: Opened codec 0x858b320, id(H264) type(Video)
> 2009-09-02 22:55:39.539 AFD: codec Unknown Codec ID has 2 channels
> 2009-09-02 22:55:39.539 AFD: Opened codec 0x85c6fd0, id(Unknown Codec ID) type(Audio)
> 2009-09-02 22:55:39.666 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> ...
> 2009-09-02 22:55:39.674 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:39.683 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:39.694 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:39.753 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:40.026 NVP: prebuffering pause
> 2009-09-02 22:55:40.695 NVP: prebuffering pause
> 2009-09-02 22:55:41.435 WriteAudio: buffer underrun
> 2009-09-02 22:55:41.559 NVP: prebuffering pause
> 2009-09-02 22:55:41.559 WriteAudio: buffer underrun
> 2009-09-02 22:55:43.548 WriteAudio: buffer underrun
> 2009-09-02 22:55:43.669 NVP: prebuffering pause
> 2009-09-02 22:55:43.670 WriteAudio: buffer underrun
> 2009-09-02 22:55:44.278 WriteAudio: buffer underrun
> 2009-09-02 22:55:44.304 NVP: prebuffering pause
> 2009-09-02 22:55:44.488 TV: Attempting to change from WatchingLiveTV to None
> 2009-09-02 22:55:44.685 TV: Changing from WatchingLiveTV to None
> 2009-09-02 22:55:44.691 DPMS Reactivated.
> 2009-09-02 22:55:46.187 Deleting UPnP client...2009-09-02 22:55:36.336 VideoOutputXv: XVideo Adaptor Name: 'NV17 Video Texture'
> 2009-09-02 22:55:37.371 AFD: Opened codec 0x9ae73f0, id(H264) type(Video)
> 2009-09-02 22:55:37.372 AFD: codec Unknown Codec ID has 2 channels
> 2009-09-02 22:55:37.372 AFD: Opened codec 0x9ae6c50, id(Unknown Codec ID) type(Audio)
> 2009-09-02 22:55:37.373 AFD: Opened codec 0x9afc840, id(DVB_SUBTITLE) type(Subtitle)
> 2009-09-02 22:55:37.379 Opening audio device 'default'. ch 2(2) sr 48000
> 2009-09-02 22:55:37.380 Opening ALSA audio device 'default'.
> ALSA lib control.c:909:(snd_ctl_open_noupdate) Invalid CTL /dev/mixer
> 2009-09-02 22:55:37.408 AudioOutput Warning: Mixer attach error -2: No such file or directory
>                         Check Mixer Name in Setup: '/dev/mixer'
> 2009-09-02 22:55:37.409 NVP: Enabling Audio
> 2009-09-02 22:55:37.425 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> ...
> 2009-09-02 22:55:37.436 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:37.526 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:37.526 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:37.705 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:37.705 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:37.893 NVP: prebuffering pause
> 2009-09-02 22:55:39.103 LiveTV forcing JumpTo 1
> 2009-09-02 22:55:39.134 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> ...
> 2009-09-02 22:55:39.141 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:39.151 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:39.255 NVP: prebuffering pause
> 2009-09-02 22:55:39.539 AFD: Opened codec 0x858b320, id(H264) type(Video)
> 2009-09-02 22:55:39.539 AFD: codec Unknown Codec ID has 2 channels
> 2009-09-02 22:55:39.539 AFD: Opened codec 0x85c6fd0, id(Unknown Codec ID) type(Audio)
> 2009-09-02 22:55:39.666 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> ...
> 2009-09-02 22:55:39.674 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:39.674 [h264 @ 0x6f667e0]number of reference frames exceeds max (probably corrupt input), discarding one
> 2009-09-02 22:55:39.683 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:39.694 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:39.753 [h264 @ 0x6f667e0]mmco: unref short failure
> 2009-09-02 22:55:40.026 NVP: prebuffering pause
> 2009-09-02 22:55:40.695 NVP: prebuffering pause
> 2009-09-02 22:55:41.435 WriteAudio: buffer underrun
> 2009-09-02 22:55:41.559 NVP: prebuffering pause
> 2009-09-02 22:55:41.559 WriteAudio: buffer underrun
> 2009-09-02 22:55:43.548 WriteAudio: buffer underrun
> 2009-09-02 22:55:43.669 NVP: prebuffering pause
> 2009-09-02 22:55:43.670 WriteAudio: buffer underrun
> 2009-09-02 22:55:44.278 WriteAudio: buffer underrun
> 2009-09-02 22:55:44.304 NVP: prebuffering pause
> 2009-09-02 22:55:44.488 TV: Attempting to change from WatchingLiveTV to None
> 2009-09-02 22:55:44.685 TV: Changing from WatchingLiveTV to None
> 2009-09-02 22:55:44.691 DPMS Reactivated.
> 2009-09-02 22:55:46.187 Deleting UPnP client...
> 

-- 
Kelvin Smith <kelvins at kelhome.dyndns.org>