draft-ietf-avt-rtp-ipmr-07.txt   draft-ietf-avt-rtp-ipmr-08.txt 
Audio/Video Transport Working Group S. Ikonin Audio/Video Transport Working Group S. Ikonin
Internet Draft SPIRIT DSP Internet Draft SPIRIT DSP
Intended status: Informational September 8, 2009 Intended status: Informational September 16, 2009
RTP Payload Format for IP-MR Speech Codec draft-ietf-avt-rtp-ipmr-07.txt RTP Payload Format for IP-MR Speech Codec draft-ietf-avt-rtp-ipmr-08.txt
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Copyright (c) 2009 IETF Trust and the persons identified as the document Copyright (c) 2009 IETF Trust and the persons identified as the document
authors. All rights reserved. authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions This document is subject to BCP 78 and the IETF Trust's Legal Provisions
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress." or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html http://www.ietf.org/shadow.html
This Internet-Draft will expire on March 8, 2010. This Internet-Draft will expire on March 16, 2010.
Abstract Abstract
This document specifies the payload format for packetization of SPIRIT This document specifies the payload format for packetization of SPIRIT
IP-MR encoded speech signals into the Real-time Transport Protocol IP-MR encoded speech signals into the Real-time Transport Protocol
(RTP). The payload format supports transmission of multiple frames per (RTP). The payload format supports transmission of multiple frames per
payload and introduced redundancy for robustness against packet loss. payload and introduced redundancy for robustness against packet loss.
Table of Contents Table of Contents
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redundancy data only. The value 6 is reserved. If receiving this value redundancy data only. The value 6 is reserved. If receiving this value
the packet SHOULD be discarded. the packet SHOULD be discarded.
o BR (3 bits): base rate for core layer of frame(s) in this packet o BR (3 bits): base rate for core layer of frame(s) in this packet
using the table for CR. Values in the range 0-5 indicate bitrates using the table for CR. Values in the range 0-5 indicate bitrates
for core layer, same as for packet SHOULD be discarded. The base for core layer, same as for packet SHOULD be discarded. The base
rate is the lowest rate for scalability, so speech payload can rate is the lowest rate for scalability, so speech payload can
be scaled down not lower than BR value. If a received packet has be scaled down not lower than BR value. If a received packet has
BR > CR then during decoding it will be assumed that BR = CR. BR > CR then during decoding it will be assumed that BR = CR.
o D (1 bit): indicates if the DTX mode is allowed or not. This o D (1 bit): indicates if the DTX mode is active or not. This
parameter is only required for a correct payload parsing. The parameter is required for payload parsing. The
particular decoder implementation must always include DTX mode decoder implementation MUST always include DTX mode
support and update internal states properly. It is prohibited support and update internal states properly. The decoder cannot
to decoder to rely this parameter is constantly off during assume that DTX will be constantly inactive during a session.
session.
o A (1 bit): byte-aligned payload. If A=1 then all speech frames o A (1 bit): byte-aligned payload. If A=1 then all speech frames
MUST be byte-aligned. This mode speeds up speech data access. MUST be byte-aligned. This mode speeds up speech data access.
The A=0 value specifies bandwidth-efficient mode with no byte The A=0 value specifies bandwidth-efficient mode with no byte
alignment(including end of header). alignment(including end of header).
o GR (2 bits): number of frames in packet (grouping size). Actual o GR (2 bits): number of frames in packet (grouping size). Actual
grouping size is GR + 1, thus maximum grouping supported is 4. grouping size is GR + 1, thus maximum grouping supported is 4.
o R (1 bit): redundancy presence bit. If R=1 then the packet o R (1 bit): redundancy presence bit. If R=1 then the packet
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