[mythtv-users] Problem Audio on Freeview HD BBC Channels

[Mike Perkins]

On 14/05/11 20:33, John Pilkington wrote:
> On 14/05/11 19:48, Duncan Brown wrote:
>> On 14/05/2011 19:23, Glenn Callow wrote:
>>> I've got Freeview HD running on a PCTV Nanostick through the work done by Steve Kerrison at http://stevekerrison.com/290e/ .
>>>
>>> I've had it running a few days, and I've noticed a problem with audio on the BBC channels through Mythfrontend.  Essentially something happens on the transition when a programme starts or stops which causes audio to be lost.  If I start a recording on the adverts between programmes, the sound plays fine but then stops as soon as the programme starts.  The reverse can also happen - start playing during a programme and you get no sound between programmes.
>>>
>>> Playing a recording through VLC exhibits the same problem - however you can get the sound to start playing again by pausing the recording once the sound stops, switching the audio track to 'Visually Impaired', then back to the standard track and resuming the recording.
>>>
>>> I've uploaded a 50MB clip which exhibits the problem at:
>>>
>>> http://www.mediafire.com/?5zx2x3zv2g6hxys
>>>
>>> Any thoughts/help appreciated.
>>>
>>> Glenn
>>>
>> Just tried it and getting exactly the same problem
>>
>> Logs fill up with
>>
>> AFD Error: Unknown audio decoding error
>> 2011-05-14 19:46:22.067 [aac_latm @ 0x34e3af7ec0]channel element 0.0 is
>> not allocated
>>
>> Running the latest 0.24 fixes from Atrpms which is currently at g97118ac
>>
>> Dunc
>
> Thanks for the clip.  Here's a mediainfo report.  Might be useful.
>
(snipped media report)
>
The problem seems to be that the audio format changes from time to time during 
the recording and this is upsetting mythtv's audio code.

Your mediainfo report will probably tell you what the format is at the beginning 
of the recording, it will say nothing about any changes in the middle of the file.

We had a similar problem in the US a while back as I recall, with the video 
format changing during advert breaks and such. I don't know how robust the audio 
code is to mid-stream format changes, but judging by the reports here, I'm 
guessing not very.

Over to you, J-Y.

-- 

Mike Perkins