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Re: [AVT] I-D Action:draft-ietf-avt-rtp-svc-19.txt
Hi Charles,
See inline below.
> -----Original Message-----
> From: Charles Eckel (eckelcu) [mailto:eckelcu at cisco.com]
> Sent: Wednesday, October 21, 2009 6:45 PM
> To: Ye-Kui Wang; avt at ietf.org
> Subject: RE: [AVT] I-D Action:draft-ietf-avt-rtp-svc-19.txt
> Importance: Low
>
> Hi YK,
>
> Thanks for the response. I have been looking into
> sprop-operation-point-info in more detail, but I unclear on a
> few key concepts that I hope you can clarify for me. Taking
> the example in 7.3.2, the following
> sprop-operation-point-info may be offered.
>
> a=rtpmap:97 H264-SVC/90000
> a=fmtp:97 profile-level-id=53000c; packetization-mode=1;
> sprop-parameter-sets={sps0},{sps1},{pps0},{pps1};
> sprop-operation-point-info=<1,0,0,0,4d400a,3200,176,144,128,
> 256>,<2,1,1,0,53000c,6400,352,288,256,512>;
>
> First, take the simple case in which the receiver supports
> SVC and wants to choose the highest operation point. In this
> case, the answer includes scalable-layer-id=2. Does this
> imply that a base layer should be sent corresponding to
> scalable-layer-id=1, with one of more enhancement layers
> being sent to a maximum of scalable-layer-id=2?
>
Yes. All the layers, including the base layer, required for decoding the
operation point corresponding to scalable-layer-id=2 will be sent in this
case.
> If the receiver supports something higher than
> scalable-layer-id=1 but lower than scalable-layer-id=2, does
> it respond with scalable-layer-id=1 and send a base layer
> corresponding to scalable-layer-id=1 but send one of more
> enhancement layers exceeding that defined for
> scalable-layer-id=1, or does it respond with
> scalable-layer-id=2 and send a base layer corresponding to
> scalable-layer-id=1 and one or more enhancement layers but
> stops short of that defined for scalable-layer-id=2.
>
In this case, the answerer responds with scalable-layer-id=1 and sends the
bitstream for the operation point with scalable-layer-id=1, and the offerer
also sends the bitstream for the operation point with scalable-layer-id=1.
Only when the offer explicitly includes more operation points, with some
corresponding to the intermediate layers, the answerer can choose one of
them.
> Is it legal to include more than two operation points in the
> sprop-operation-point-info? The following text makes it sound
> to me as if there is a limit of two.
>
Yes, you can explicitly include many operation points. The following text
does not have that implication (at least to me).
BR, YK
> If the sprop-operation-point-info is followed by exactly one
> operation-
> point-description vector, this describes the highest
> operation
> point contained in the RTP session. If there are exactly two
> operation-point-description vectors, the first describes the
> lowest and the second describes the highest operation point
> contained in the RTP session.
>
> Thanks,
> Charles
>
> > -----Original Message-----
> > From: Ye-Kui Wang [mailto:yekuiwang at huawei.com]
> > Sent: Wednesday, October 21, 2009 7:04 AM
> > To: Charles Eckel (eckelcu); avt at ietf.org
> > Subject: RE: [AVT] I-D Action:draft-ietf-avt-rtp-svc-19.txt
> >
> >
> > Once you are able to signal layering scheme in SDP, you are able to
> > negotiate layering scheme. To indicate specific resolution and frame
> rate
> > values, you can use the media type parameter
> sprop-operation-point-info.
> > When providing an SVC stream, it is by default (and
> mandated) that the
> base
> > layer is AVC compatible. Therefore I don't see anything missing.
> >
> > If the above does not answer your question well, perhaps
> you could try
> to
> > re-elaborate your question.
> >
> > BR, YK
> >
> > > -----Original Message-----
> > > From: Charles Eckel (eckelcu) [mailto:eckelcu at cisco.com]
> > > Sent: Tuesday, October 20, 2009 6:59 PM
> > > To: Ye-Kui Wang; avt at ietf.org
> > > Subject: RE: [AVT] I-D Action:draft-ietf-avt-rtp-svc-19.txt
> > > Importance: Low
> > >
> > > Perhaps I am missing some fundamental aspects of the
> draft; however,
> > > in reading over it, I do not understand how one would convey the
> > > desired layering scheme. For example, if when using SVC it is
> > > desired for the base layer to be AVC compatible with a given
> > > resolution and frame rate, then for temporal and spatial
> enhancement
> > > layers to be added on top, how would one signal that. The
> example in
> > > section 7.3.1 illustrates offering an AVC compatible
> stream and an
> > > SVC compatible stream; however, it does not illustrate how to
> > > request that if SVC is supported (97) a specific layering
> scheme is
> > > used that includes an AVC compatible base layer with a specific
> > > resolution and frame rate.
> > > Being able to negotiate the layering scheme in SDP seems useful to
> me.
> > > Was this considered?
> > >
> > > Thanks,
> > > Charles
> > >
> > > > -----Original Message-----
> > > > From: avt-bounces at ietf.org [mailto:avt-bounces at ietf.org] On
> > > Behalf Of
> > > Ye-Kui Wang
> > > > Sent: Thursday, September 17, 2009 9:57 AM
> > > > To: avt at ietf.org
> > > > Subject: Re: [AVT] I-D Action:draft-ietf-avt-rtp-svc-19.txt
> > > >
> > > >
> > > >
> > > > Changes compared to -18 are list below, among other minor
> editorial
> > > changes:
> > > >
> > > > - alignment of recent changes to the RFC 3984bis draft
> > > > - update of some references for which the RFCs are now available
> > > > - SDP examples are now in line with RFC5583
> > > > - change of Stephan's affiliation and address
> > > > - change of Thomas' email address
> > > >
> > > > I hope Chairs could issue a second WGLC for this draft.
> > > >
> > > > BR,YK
> > > >
> > > > > -----Original Message-----
> > > > > From: avt-bounces at ietf.org [mailto:avt-bounces at ietf.org]
> > > On Behalf
> > > > > Of Internet-Drafts at ietf.org
> > > > > Sent: Thursday, September 17, 2009 12:45 PM
> > > > > To: i-d-announce at ietf.org
> > > > > Cc: avt at ietf.org
> > > > > Subject: [AVT] I-D Action:draft-ietf-avt-rtp-svc-19.txt
> > > > >
> > > > > A New Internet-Draft is available from the on-line
> > > Internet-Drafts
> > > > > directories.
> > > > > This draft is a work item of the Audio/Video Transport
> > > Working Group
> > > > > of the IETF.
> > > > >
> > > > >
> > > > > Title : RTP Payload Format for SVC Video
> > > > > Author(s) : S. Wenger, et al.
> > > > > Filename : draft-ietf-avt-rtp-svc-19.txt
> > > > > Pages : 103
> > > > > Date : 2009-09-17
> > > > >
> > > > > This memo describes an RTP payload format for Scalable
> > > Video Coding
> > > > > (SVC) as defined in_Annex G of ITU-T Recommendation
> > > H.264, which is
> > > > > technically identical to Amendment 3 of ISO/IEC International
> > > > > Standard 14496-10. The RTP payload format allows for
> > > packetization
> > > > > of one or more Network Abstraction Layer (NAL) units
> in each RTP
> > > > > packet payload, as well as fragmentation of a NAL unit in
> > > multiple
> > > > > RTP packets.
> > > > > Furthermore, it supports transmission of an SVC stream
> > > over a single
> > > > > as well as multiple RTP sessions. The payload format
> > > defines a new
> > > > > media subtype name "H264-SVC", but is still backwards
> > > compatible to
> > > > > [I-D.ietf-avt-rtp-rfc3984bis] since the base layer, when
> > > > > encapsulated in its own RTP stream, must use the H.264
> > > media subtype
> > > > > name ("H264") and the packetization method specified in [I-
> > > > > D.ietf-avt-rtp-rfc3984bis]. The payload format has wide
> > > > > applicability in videoconferencing, Internet video streaming,
> and
> > > > > high bit-rate entertainment-quality video, among others.
> > > > >
> > > > > A URL for this Internet-Draft is:
> > > > >
> http://www.ietf.org/internet-drafts/draft-ietf-avt-rtp-svc-19.txt
> > > > >
> > > > > Internet-Drafts are also available by anonymous FTP at:
> > > > > ftp://ftp.ietf.org/internet-drafts/
> > > > >
> > > > > Below is the data which will enable a MIME compliant
> mail reader
> > > > > implementation to automatically retrieve the ASCII version of
> the
> > > > > Internet-Draft.
> > > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > Audio/Video Transport Working Group avt at ietf.org
> > > > https://www.ietf.org/mailman/listinfo/avt
> > >
> >
>
>