[M4IF Technotes] Bifs-text scene description - streaming movietexture

[Nicholas Smit]

> Hi Nicholas,
> 
> I'm very curious if somebody answered your questions already. 
> I really  
> would like to know the answers as well.

Hi Mathijn - thanks for the info you sent in that url. 
Yes, a lot of people have helped trying to answer this - big thanks to
Cyril, Guido, JC and Mikael.
The short answer, as far as I can work out, is that yes you are correct:
It is theoretically possible, but hasn't been defined - not by ISMA or
MPEG / ISO. Largely due to lack of interest, apparently.(!)
What would work, is to write your own (or extend another) server so that
it can parse something like rtsp://example.com/stream.mp4#1 to return
the first track in stream.mp4, or similar.  This is given that your
player understands rtsp. 
If your OD looked like this:
		ObjectDescriptor {
			objectDescriptorID 20
			esdescr [
				ES_Descriptor {
					es_id 3
					URLString
"rtsp://localhost:554/..."
					decConfigDescr
DecoderConfigDescriptor {
						objectTypeIndication 32
						streamType 4
						decSpecificInfo
DecoderSpecificInfoString {
						}
					}
					slConfigDescr SLConfigDescriptor
{ ... }
				}
			]
		}
Cyril noted that "Here the URL shall point to a SL-packetized stream
following the SLConfigDescriptor. You could point to a particular track
in a remote mp4. In that case, the SLConfigDescriptor is empty. But
again, I'm not sure that MPEG has standardized the way to access a track
within an MP4 file."
HTH.
Kind regards,
Nik.
> 

> 
> That url business is quite tricky and there are no really 
> good sources  
> about it.
> The delivery faq, section 24 specifies which url's will be 
> supported,  
> however:
> 	http://mpeg.telecomitalialab.com/faq/mp4-dmi/mp4-dmi.htm#24
> 
> I also know that Envivio supports live broadcasts of video 
> and audio,  
> so it should be possible. I don't know which url syntax they use for  
> it... and if it is the standarized way to do it.
> I also know that they allow streaming of content from within 
> the same  
> file, but that it is not possible to do it cross-file. The latter is  
> only possible with Inline nodes. But as you said, that is not really  
> flexible enough.
> 
> What I get from the standard, is that it should all be possible in  
> theory. I think we've to wait for the implementations...
> 
> Please let me know of any answers you receive...
> 
> Best regards,
> 
> Mathijn
> 
> On Tuesday, Oct 15, 2002, at 14:33 Europe/Amsterdam, Nicholas Smit  
> wrote:
> 
> >> Hi,
> >>
> >> Movie textures are not supported in any streaming standard
> >> (RFC 3016 or ISMA). Neither do I know about any proprietary
> >> way of doing it. You may have to device your own scheme for this.
> >>
> >> Regards,
> >> Parimal.
> >>
> >
> >
> > Hmmm, so then how are applications like (implemented 
> versions of) the
> > following from enst supposed to work?
> >
> > http://161.58.176.70/downloads/content/MIRRORSITE/interoperability/ 
> > ENST/
> > ecran2.mp4
> >
> > Inlineing the sources is fine, until you want to manipulate 
> them in  
> > some
> > way, such as full screening them....
> >
> >
> > Thanks,
> > Nik.
> >
> >
> >
> >> -----Original Message-----
> >> From: Nik [mailto:salo   rucus.ru.ac.za]
> >> Sent: Tuesday, October 15, 2023 2:22 AM
> >> To: technotes   lists.m4if.org
> >> Subject: [M4IF Technotes] Bifs-text scene description -
> >> streaming movietexture
> >>
> >>
> >> Hi streaming experts,
> >>
> >> I'd really appreciate help with this.
> >>
> >> I need a movietexture that uses live video as its source,
> >> such as "rtsp://localhost:554/vid.mp4".
> >>
> >> How do you specify the OD's and the ESD's for this?
> >>
> >> Can anyone give me some pointers on this, or even the url to
> >> a similar mp4 on the net somewhere?
> >>
> >> I'm also a little confused as to how a player will know which
> >> track to use from a url like "rtsp://localhost:554/vid.mp4"
> >> for the movietexture....?
> >>
> >>
> >> Any help very appreciated.
> >>
> >> Kind regards,
> >> Nicholas.
> >>
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> >>
> >
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> >
> < Mathijn Elhorst | Lead Developer
> 
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