[mythtv-users] The future of MythTV

Mike Perkins mikep at randomtraveller.org.uk
Tue Jun 8 11:22:57 UTC 2021

On 08/06/2021 10:57, John Pilkington wrote:
> On 08/06/2021 10:00, Stuart Auchterlonie wrote:
>> On 08/06/2021 09:55, Per Jessen wrote:
>>> John Pilkington wrote:
>>>> On 04/06/2021 20:39, Per Jessen wrote:
>>>>> Also, the ability to specify the language of the audio stream(s) when
>>>>> recording would be nice - I get lots of recordings in languages I
>>>>> don't understand.
>>>> Playback in Mythfrontend has the NEXTAUDIO key, by default + , which
>>>> ought to step through the available options.  For DVB-T/T2 in the UK I
>>>> think that usually gives an
>>>> audio-description-for-the-visually-handicapped track, but you will
>>>> probably have others.
>>> Yes, that works very well, but it would be nice to say "record this
>>> title, but only if it has sound in one of (lang1,lang2)"  - popular
>>> series are often broadcast in many countries, and often in local
>>> language only.  Back when "The Big Bang Theory" was a big hit, I would
>>> have recordings in four-five different languages :-)
>>> With Swiss telly alone it can be an issue too, but it is easy to tidy
>>> up.
>> I would be suprised if there was sufficient meta data available for the
>> scheduler to be able to make this decision.
>> With digital tv these days, they typically broadcast multiple languages
>> in different streams at the same time, so a single recording would have
>> all the broadcast languages in it
>> Regards
>> Stuart
> It might be possible to start a recording, check the available streams, and abort on a language-set 
> mismatch.
> I just had a BBC FOUR recording that started at 18:58 and now plays fine in master, but the stream 
> analysis in my cutting script saw 0 video streams and aborted.  It worked after dropping the first 
> 45 MB of the file.  Needs a probe offset...
The problem with starting any digital recording comes with two problems: pre-roll and adverts.

Pre-roll is almost guaranteed to pick up the previous program which may have different language 
selections[1]. OK, you can use an offset to start the check but how accurate is your clock against 
that of the broadcaster? Some are known to start programs early, others late.

Adverts and/or trailers could also have different selections and, especially adverts, can occur 
randomly throughout the program. How can the software tell which is which?

[1] Unless it is a part-time channel like BBC4 in which case you could get absolutely nothing!


Mike Perkins

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