[Bug 753323] mpegts: add support for JPEG 2000 to mpegtsmux and tsdemux

GStreamer (GNOME Bugzilla) bugzilla at gnome.org
Thu Jul 20 13:19:43 UTC 2017


https://bugzilla.gnome.org/show_bug.cgi?id=753323

--- Comment #129 from Aaron Boxer <boxerab at gmail.com> ---
(In reply to Sebastian Dröge (slomo) from comment #127)
> (In reply to Aaron Boxer from comment #124)
> 
> > > (In reply to Aaron Boxer from comment #120)
> > > 
> > > > > Is a fixed framerate required, or can it be 0/1 or 0/0?
> > 
> > From what I can see, frame rate is fixed, so 0/0 is not allowed. Also,
> > frame rate of 0 is not allowed according to spec, so 0/1 also not allowed.
> 
> So you need to require a framerate in the caps, and it must be higher than
> 0/1. And this also makes it required that the input is actually fixed
> framerate.
> 
> Seems like a weird requirement for MPEG-TS... are you sure about that? Or
> maybe the framerate is only an indication, not necessarily to be correct?

No, not sure. Since timecode box is mandatory, doesn't this rule out variable
frame rate?



> 
> > 
> > Time code box is mandatory. So, pretty sure that framerate is fixed.
> > From spec, range for time code is:
> > 
> > HH (0-23)
> > MM (0-59)
> > SS (0-59)
> > FF (1-60)
> 
> Ok, so you must invent your own timecode with the API if there is no meta
> with an actual timecode on the stream. Or you error out directly if there is
> no timecode meta, and require the user to use the timecodestamper element. I
> think I prefer requiring timecodestamper.
> 
> You also require videorate to be used for a fixed framerate.
> 

Alright, thanks.


> > > What does the spec say exactly for these values? You probably want color
> > > primaries or the matrix here then.
> > 
> > Colour spec is described in a different document that I don't have access to.
> > But I do know the following:
> > 
> > sRGB 0x01
> > Rec-601 0x02
> > Rec-709 0x03
> > CIE-LUV 0x04
> > CIE-XYZ 0x05
> > Rec-2020 0x06
> > SMPTE-2084 0x07
> 
> Ok, you need to research then a bit if this is the whole colorimetry, the
> primaries, the matrix or a combination of them :)
> 
> Maybe check another implementation of the JPEG2000 in MPEG-TS spec also?

Thanks, will do.

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