Subject: [payload] #1: Temporal scalability in VP8

From: "payload issue tracker" <[email-masked]>
Date: Tue, 10 Dec 2013 02:03:29 -0000

#1: Temporal scalability in VP8

 Section 1 states:

 In summary, the payload format described in this document enables a number
 of features in VP8, including:

 ·        Temporal scalability.

 However, Section 6 doesn’t include information on format parameters or O/A
 considerations relating to temporal scaling.

 It appears that VP8 transports all temporal layers in a single RTP session
 utilizing a single SSRC (e.g. Single Session Transport), so that RFC 5583
 does not apply, correct?

 Other than the max-fr parameter, is there anything that provides an
 indication of the capabilities of the receiver?  Or is the encoder free to
 utilize any configuration that fits within the max-fr parameter?

 For example, if the Offer includes max-fr=60, does that mean that the
 receiver is prepared to handle any of the following?

 a.       T0 = 60 fps (no temporal scalability)
 b.       T0 = 30 fps, T1 = 30 fps
 c.       T0 = 15 fps, T1 = 15 fps, T2=30 fps
 d.       T0 = 7.5 fps, T1 = 7.5 fps, T2 = 15 fps, T3 = 30 fps

-- 
-------------------------------------+-------------------------------------
 Reporter:                           |      Owner:  draft-ietf-payload-
  [email-masked]          |  [email-masked]
     Type:  defect                   |     Status:  new
 Priority:  major                    |  Milestone:  milestone1
Component:  vp8                      |    Version:
 Severity:  Active WG Document       |   Keywords:
-------------------------------------+-------------------------------------

Ticket URL: <http://tools.ietf.org/wg/payload/trac/ticket/1>
payload <http://tools.ietf.org/payload/>

---

From: "payload issue tracker" <[email-masked]>
Date: Wed, 11 Dec 2013 11:53:17 -0000

Comment (by [email-masked]):

 As far as I understand, the temporal scalability is enabled by the
 features described in section 4.2, and all receivers of this format are
 required to handle all combinations of parameters used here.

 Thus, there is no need for signalling the actual scalability parameters
 used; it's an unilateral encoder choice.

 Severity:  Active WG Document       |  Resolution:
 Keywords:                           |

Ticket URL: <http://tools.ietf.org/wg/payload/trac/ticket/1#comment:1>
payload <http://tools.ietf.org/payload/>