[mythtv-users] HD-PVR Dropouts

Tue Feb 23 06:01:23 UTC 2010

On 2/22/10 6:59 PM, Richard Woelk wrote:
>
> Douglas Choma wrote:
>> On 2/18/10 2:30 PM, greg wrote:
>>> Douglas Choma wrote:
>>>> On 2/18/10 8:01 AM, greg wrote:
>>>>> Douglas Choma wrote:
>>>>>> I'm experiencing a similar issue after moving to 0.22-fixes (and 
>>>>>> 0.23 trunk).
>>>>>>
>>>>>> When watching live tv and changing the channel, I get the 
>>>>>> following error on the backend...
>>>>>> DevRdB(/dev/video0) Error: Poll giving up
>>>>>> MPEGRec(/dev/video0) Error: Device error detected
>>>>>> DevRdB(/dev/video0): Stop(): Not running.
>>>>>>
>>>>>> And this happens on the frontend...
>>>>>> [aac @ 0x7f2128a14920]channel element 0.5 is not allocated
>>>>>> audio stream changed
>>>>>> DEnc, Error: Could not open codec, invalid bitrate or samplerate
>>>>>> Segmentation fault
>>>>>>
>>>>>> I'm guessing this has to be an issue with Myth, because the same 
>>>>>> setup worked when I was using 0.22 from trunk.  It only started 
>>>>>> after 0.22 moved to stable.
>>>>>>
>>>>>> I get the same results with the 0.23 trunk.
>>>>>>
>>>>>> Here's my current build...
>>>>>> MythTV Version   : 23504M
>>>>>> MythTV Branch    : trunk
>>>>>> Network Protocol : 56
>>>>>> Library API      : 0.23.20100131-1
>>>>>> QT Version       : 4.4.3
>>>>>> Options compiled in:
>>>>>>  linux release using_oss using_alsa using_backend using_dvb 
>>>>>> using_firewire using_frontend using_hdhomerun using_hdpvr 
>>>>>> using_iptv using_ivtv using_joystick_menu using_lirc using_mheg 
>>>>>> using_opengl_video using_opengl_vsync using_qtwebkit using_v4l 
>>>>>> using_x11 using_bindings_perl using_bindings_python using_opengl 
>>>>>> using_ffmpeg_threads using_libavc_5_3 using_live using_mheg
>>>>> I am running trunk and have been since the HDPVR became available. 
>>>>> I don't experience the problems you are seeing.. My setup is 
>>>>> pretty stable.. I compared my setup to yours and they are very 
>>>>> similar...  I am running a newer version of Myth,plus a different 
>>>>> version of QT...
>>>>> The only problem I've had with the HDPVR was it was switching 
>>>>> nodes,but with the help of a few people on here I got that working...
>>>>> OS Ubuntu 9.10 Nvidia 195.36.03
>>>>>
>>>>> MythTV Version   : 23567
>>>>> MythTV Branch    : trunk
>>>>> Network Protocol : 56
>>>>> Library API      : 0.23.20100212-1
>>>>> QT Version       : 4.5.2
>>>>> Options compiled in:
>>>>> linux debug using_oss using_alsa using_backend using_dvb 
>>>>> using_frontend using_hdhomerun using_hdpvr using_iptv using_ivtv 
>>>>> using_joystick_menu using_lirc using_mheg using_opengl_video 
>>>>> using_opengl_vsync using_qtdbus using_qtwebkit using_v4l using_x11 
>>>>> using_xrandr using_xv using_bindings_perl using_bindings_python 
>>>>> using_opengl using_vdpau using_ffmpeg_threads using_live using_mheg
>>>>
>>>> Thanks Greg,
>>>>
>>>> Are you running any patches against trunk?  I noticed the wiki 
>>>> still mentions "recommended" patches, which I've applied.  It 
>>>> sounds like I might just need to purge everything and do a clean 
>>>> build.
>>>>
>>>> Which version of the v4l-dvb drivers are you working with?
>>>>
>>>>
>>> No, I have don't have any patches installed ..Since I moved to 
>>> Ubuntu 9.10 the driver just works...
>>
>> Anybody have advice for other things to try debugging?  This is 
>> driving me nuts.  :-(
>>
>> I did a clean build on both the backend and the frontend from trunk, 
>> which seems to have cured the segfaults on my frontend.  But I still 
>> get the audio errors when I change channels on LiveTV.  The video 
>> changes fine, but the audio is missing after a channel change.  If I 
>> exit LiveTV and go back, everything tunes in without error.  So it's 
>> only switching from one stream to another that causes problems.
>>
>> I'm using the latest firmware, the most current driver, and myth 
>> trunk (23578).  This problem never occurred until the 0.22 branch 
>> went mainstream.  I had been using the 0.22 trunk with HD-PVR without 
>> issue.
>>
>> The frontend goes bezerk with these errors when I change channels...
>> ###
>> audio stream changed
>> AO: Using resampler. From: 88200 to 192000
>> Opening audio device 'default'. ch 2(1) sr 192000 (reenc 0)
>> Opening ALSA audio device 'default'.
>> AFD Error: Unknown audio decoding error
>> [aac @ 0x7ff558ffeb20]Error decoding AAC frame header.
>> AFD Error: Unknown audio decoding error
>> [aac @ 0x7ff558ffeb20]Not evaluating a further program_config_element 
>> as this construct is dubious at best.
>> [aac @ 0x7ff558ffeb20]channel element 1.5 is not allocated
>> audio stream changed
>> AO: Using resampler. From: 24000 to 192000
>> Opening audio device 'default'. ch 2(1) sr 192000 (reenc 0)
>> Opening ALSA audio device 'default'.
>> AFD Error: Unknown audio decoding error
>> [aac @ 0x7ff558ffeb20]Error decoding AAC frame header.
>> AFD Error: Unknown audio decoding error
>> [aac @ 0x7ff558ffeb20]channel element 3.0 is not allocated
>> audio stream changed
>> AO: Using resampler. From: 7350 to 192000
>> Opening audio device 'default'. ch 2(1) sr 192000 (reenc 0)
>> Opening ALSA audio device 'default'.
>> AFD Error: Unknown audio decoding error
>> [aac @ 0x7ff558ffeb20]Error decoding AAC frame header.
>> AFD Error: Unknown audio decoding error
>> [aac @ 0x7ff558ffeb20]channel element 0.4 is not allocated
>> ###
>
>
> I have been using an HD-PVR since it came out as well, but on Fedora. 
> I currently use compiled trunk packages from ATRPMS, which now is 
> version 23405. I use the driver that comes with the kernel, I have not 
> needed to compile the driver in a while.  - my current kernel is 
> 2.6.30.10-105.2.16.fc11.x86_64
>
> I also have had trouble changing channels with live tv, I had to set a 
> 5 second delay in my channel change script to get it to work. It turns 
> out, it takes that long for my set top box to "settle down" after 
> changing channels. I rarely use livetv, so I usually leave that delay 
> commented out.
>
> - Richard

Interesting.  So it sounds like it might be caused when Myth tries to 
start the new stream before the cable box is ready to go.  Sadly, the 
audio decoding never seems to settle down.  Unless I exit LiveTV, that 
audio decoding error goes on indefinitely.

I wonder if there's some way (aside from hacking the driver) that I 
could get the audio to reinitialize a few seconds after the channel change.

How are you able to introduce the delay in your channel changing script?