[mythtv-users] real format of .nuv from DVB-T card (mpeg2 with
no header?)
Jesper Sörensen
jesper at datapartner.se
Tue Aug 16 12:45:09 UTC 2005
ffrr skrev:
> Jesper Sörensen wrote:
>
>> ffrr wrote:
>>
>>> I think you misunderstood. I know what is required for DVD. I was
>>> asking the difference between that, and what comes out of the DVB
>>> card as a program stream (which is what is in the nuv file myth
>>> creates).
>>
>>
>>
>> DVB cards deliver the data in the raw TS format so this is the most
>> "pure" form you can record in. The TS->PS conversion is performed by
>> Myth if you're in PS mode, but that code isn't 100% kosher so it might
>> or might not work depending on what you need.
>>
>>> People keep saying the PS is mpeg 2, and I know it is 720x576 etc
>>> (haven't checked bitrates yet). So what is it missing (and if it's
>>> the header that DVDstyler says is missing, how do you put the header
>>> on)?
>>
>>
>>
>> It's not a header. TS and PS are different ways to hold the data. It's
>> possible to convert losslessly between the two, but it's not trivial,
>> and definitely not as simple as smacking on an extra header or
>> something...
>> _______________________________________________
>
>
>
> No, the file is _already_ in ps format. It's this ps format file that
> DVDstyler says is missing a header. Given the new info you have just
> told me, that the myth TS to PS conversion code isn't '100% kosher',
> then maybe that's the reason.
You could try to use replex or some other tool to remultiplex it (from
PS to PS).
> Actually the conversion mustn't be all
> that hard, as Kaffeine, and also the Windows software that came with my
> Twinhan card, both offered the PS mode as an alternative recording
> method.
As I said there are lots of tools for this but their quality vary, and I
don't know which one is best.
I'm no expert so if you need more info you'll need to read the MPEG-2
system spec, google or trawl the archives. For your info, this is what
Marcus Metzler said about it (myth-dev list, 2004-11-25, subject "DVB
subtitles and TS->PES decoder"):
"AFAIKT the TS to PES conversion uses my routines from the
dvb-mpegtools package. This is good enough for a quick and dirty
transformation, but can not be used for e.g. authoring DVDs where you
have to get the muxing correct and add some more time stamps. That's
why I started dvb-replex (see http://www.metzlerbros.org/dvb/index.html)"
> Maybe the card itself can output either mode?
Not likely. TS is what comes through the air (or cable if you're on
DVB-C), so if you get PS from the card there is a converter somewhere in
the data path (probably in the application). I guess it would be
possible to put a converter in the card's driver or possibly in the
card's hardware but I've never heard of such a thing.
> Anyway I could record in ts format and try using the command line ts2ps
> conversion tool I suppose.
Yup.
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