[FFmpeg-devel] [NUT-devel] NUT version bump

[Michael Niedermayer]

On Wed, May 15, 2013 at 01:32:37PM +0200, Luca Barbato wrote:
> On 05/15/2013 01:21 PM, Michael Niedermayer wrote:
> > interresting idea.
> > 
> > I would suggest the following:
> > * leave the transmit_ts as it is
> > * add a field to the main header that contains the wallclock transmit
> >   time corresponding to the transmit_ts == 0
> > 
> > This should avoid the need to bump the version, improving
> > compatibility as old demuxers will be able to read it (they would
> > reject VERSION>3)
> > 
> > Its more space efficient than storing a full wallclock timestamp as
> > the 0 based timestamps would be smaller in value and take up fewer
> > bytes
> 
> Surely feasible, since it is a real-time information can stay on the
> global header w/out problems.

The wallclock time corresponding to the transmit_ts of 0 does not
change throughout the stream. Its just the origin / zero point from
where you count time

Its like the day you are born does not change and can be written in
your birth certificate. While your age changes in relation
to your "birth date" (realtime) over your life.

That is instead of
packet 123  transmit time = 2013 01 02 03:04:05.00
packet 124  transmit time = 2013 01 02 03:04:05.02
packet 125  transmit time = 2013 01 02 03:04:05.03

one can use:
main_header reference_wallclock = 2013 01 02 00:00:00.00
...
packet 123  transmit time = 03:04:05.00
packet 124  transmit time = 03:04:05.02
packet 125  transmit time = 03:04:05.03

Its the same information, just requires fewer bytes to transmit/store
and the stream can continue realtime for millions of years with the
same main header if someone really wanted

Though i suspect the stream would be restarted several times a year
with new video resolutions, audio sample rates, audio & video codecs
and other change

I hope that clarifies what i was suggesting

Thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Let us carefully observe those good qualities wherein our enemies excel us
and endeavor to excel them, by avoiding what is faulty, and imitating what
is excellent in them. -- Plutarch
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