[NUT-devel] a few things about nut.txt

[Måns Rullgård]

Rich Felker said:
> On Sun, Nov 26, 2006 at 05:37:25AM -0000, Måns Rullgård wrote:
>> >> > > > > * nut files with EOR cannot be converted to other containers or more
>> >> > > > >   correctly you cannot seek correctly in the resulting file
>> >> > > >
>> >> > > > Not true.
>> >> > >
>> >> > > wait, EOR is "absolutely needed" and it works in containers which dont
>> have
>> >> > > EOR, how can both be true?
>> >> >
>> >> > Other containers don't support correct seeking with subtitles unless
>> >> > they have an index of all subtitles.
>> >>
>> >> i dont think this is true, maybe someone who knows the details about subs
>> >> in mpeg-ps/ts could clarify but my suspicion is that there are rules in the
>> >> relevant specs which ensure that the correct subs are displayed after
>> >> seeking, and most other containers which support subs have an index ...
>> >
>> > I'm quite sure mpeg-ps/ts make no provision for this.
>>
>> The ISO MPEG PS/TS specs do not mention any subtitles.  The DVD and DVB specs
>> add their own subtitle formats to PS and TS, respectively.
>
> Well, do they provide any mechanism to ensure that you have the
> correct subtitle displayed after seeking?

DVB doesn't care about seeking at all.  That is a problem for recorders to solve
as they see fit.  I'm not sure about DVD, and quite frankly, I don't care.  If
the subtitles for the first line of dialog after a seek are missing, so what?

>> As for timestamp resets, you can't avoid them when broadcasting 24/7, unless
>> you have infintely large timestamp fields.
>
> 64bit is long enough to run without problem until well past the end of
> the solar system... provided you don't choose timebase idiotically. :)
> Unfortunately I think mpeg uses 33bit or something and also uses
> idiotic timebase.

Why is the MPEG time base idiotic?  90kHz is nicely divisible by all the allowed
frame rates.

-- 
Måns Rullgård
mru at inprovide.com