[mythtv-users] live tv no audio external channel changer

[atemp at tpg.com.au]

Any ideas why on the first tune of a channel on live TV audio is OK:
See log extract:
2011-01-09 08:03:35.405 AO: Original codec was NONE, signed 16 bit, 48 kHz, 2 channels
2011-01-09 08:03:35.405 AO: enc(0), passthru(0), canAC3(1), canDTS(1), canLPCM(0), 
configured_channels(2), 2 channels supported(1)
2011-01-09 08:03:35.405 AO: Opening audio device 'iec958:CARD=SB,DEV=0' ch 2(2) sr 48000 sf 
signed 16 bit reenc 0
2011-01-09 08:03:35.405 ALSA: SetParameters(format=2, channels=2, rate=48000, 
buffer_time=200000, period_time=50000)
2011-01-09 08:03:35.405 ALSA: Buffer time = 200000 us
2011-01-09 08:03:35.405 ALSA: Period time = 50000 us
2011-01-09 08:03:35.410 ALSA: Buffer size = 9600 | Period size = 2400
2011-01-09 08:03:35.422 ALSA: found playback control Master on mixer device default
2011-01-09 08:03:35.422 ALSA: mixer volume range on mixer device default/Master - min 0, max 
64, range 64
2011-01-09 08:03:35.422 ALSA: mixer device default/Master set up successfully
2011-01-09 08:03:35.423 ALSA: channel 0 volume set 0 => 0
2011-01-09 08:03:35.423 ALSA: channel 1 volume set 0 => 0
2011-01-09 08:03:35.423 ALSA: get volume channel 0: 0
2011-01-09 08:03:35.423 ALSA: channel 0 volume set 0 => 0
2011-01-09 08:03:35.423 ALSA: channel 1 volume set 0 => 0
2011-01-09 08:03:35.423 AO: Audio fragment size: 4800
2011-01-09 08:03:35.423 AO: Audio Stretch Factor: 1
2011-01-09 08:03:35.423 AO: Ending Reconfigure()
2011-01-09 08:03:35.423 AudioPlayer: Enabling Audio


But fails when changing channels.  see below
2011-01-09 08:04:16.348 RingBuf(/tv/2005_20110109080415.nuv) Warning: Not starting read 
ahead thread, already running
2011-01-09 08:04:21.337 VDPAU Painter: Clearing VDPAU painter cache.
2011-01-09 08:04:21.339 MythPainter: 9 images not yet de-allocated.
2011-01-09 08:04:21.418 VDPAU: Created 2 output surfaces.
2011-01-09 08:04:21.418 VDPAU: Created VDPAU render device 1280x768
2011-01-09 08:04:21.433 AFD Warning: ScanATSCCaptionStreams() called with no PMT
2011-01-09 08:04:21.434 AFD: Opened codec 0x86ee650, id(MPEG4) type(Video)
2011-01-09 08:04:21.434 AudioPlayer: Disabling Audio, params(0,-1,-1)
2011-01-09 08:04:21.434 AO: Killing AudioOutputDSP
2011-01-09 08:04:21.443 AO: OutputAudioLoop: Stop Event
2011-01-09 08:04:21.443 AO: kickoffOutputAudioLoop exiting
2011-01-09 08:04:21.629 Pulse: PulseAudio not running
2011-01-09 08:04:21.632 AO: Sample rate 44100 is supported
2011-01-09 08:04:21.632 AO: Sample rate 48000 is supported
2011-01-09 08:04:21.632 AO: Sample rate 88200 is supported
2011-01-09 08:04:21.632 AO: Sample rate 96000 is supported
2011-01-09 08:04:21.632 AO: Sample rate 192000 is supported
2011-01-09 08:04:21.632 AO: 2 channel(s) are supported
2011-01-09 08:04:21.640 AO: AC3 or DTS capable
2011-01-09 08:04:21.640 AO: 6 channel(s) are supported
2011-01-09 08:04:21.640 AO: Killing AudioOutputDSP
2011-01-09 08:04:21.640 AudioPlayer: Disabling Audio, reason is: Aborting Audio Reconfigure. 
Invalid audio parameters ch -1 fmt 0 @ -1Hz






On Sun, Jan 9th, 2011 at 8:16 AM, atemp at tpg.com.au wrote:

> I have a problem with losing audio when changing channels on an external
> satellite tuner.
> 
> The problem occurs in 0.24-fixes after an upgrade from 0.23-fixes.  I have
> had the same setup for 
> 4-5 years.  My external foxtel satellite decoder is connected to myth via
> the composite input of a 
> software V4L decoder and the audio via the sound cards line input.
> 
> On initial tuning of the channel, all is fine, video and audio is present.
>  Hence my recording are OK.
> 
> However, on Live TV, the initial tuning is OK with audio and video, but if
> I change channels audio is 
> lost.  Also the changing of channels seems to take a considerably longer
> time than previously.
> 
> It would seem to be Myth's changes to external tuners, as if I do not
> change channel via myth, but 
> only on the external tuner, bypassing the channel changing script, then
> audio is not lost.  Perhaps 
> commits 25543 / 25544 ?
> 
> Does anyone know whether this is a known problem with 0.24, or a change in
> setup that may be 
> required?
> 
> I attach a frontend log with verbose audio showing audio detected for the
> initial tune and then lost 
> during a channel change.
> 
> BTW: I also have a number of DVB cards.  Channel changing is not a problem
> on these.