draft-ietf-avt-rtp-evrc-nw-01.txt   draft-ietf-avt-rtp-evrc-nw-02.txt 
Network Working Group Z. Fang Network Working Group Z. Fang
Internet-Draft Qualcomm Internet-Draft Qualcomm
Intended status: Standards Track July 26, 2010 Intended status: Standards Track November 30, 2010
Expires: January 27, 2011 Expires: June 3, 2011
RTP payload format for Enhanced Variable Rate Narrowband-Wideband Codec RTP payload format for Enhanced Variable Rate Narrowband-Wideband Codec
(EVRC-NW) (EVRC-NW)
draft-ietf-avt-rtp-evrc-nw-01 draft-ietf-avt-rtp-evrc-nw-02
Abstract Abstract
This document specifies real-time transport protocol (RTP) payload This document specifies real-time transport protocol (RTP) payload
formats to be used for the Enhanced Variable Rate Narrowband-Wideband formats to be used for the Enhanced Variable Rate Narrowband-Wideband
Codec (EVRC-NW). Three media type registrations are included for Codec (EVRC-NW). Three media type registrations are included for
EVRC-NW RTP payload formats. In addition, a file format is specified EVRC-NW RTP payload formats. In addition, a file format is specified
for transport of EVRC-NW speech data in storage mode applications for transport of EVRC-NW speech data in storage mode applications
such as e-mail. such as e-mail.
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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 time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 27, 2011. This Internet-Draft will expire on June 3, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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receiver. EVRC-NW provides a standardized solution for packetized receiver. EVRC-NW provides a standardized solution for packetized
voice applications that allow transitions between enhanced quality voice applications that allow transitions between enhanced quality
and increased capacity. The most important service addressed is IP and increased capacity. The most important service addressed is IP
telephony. Target devices can be IP phones or VoIP handsets, media telephony. Target devices can be IP phones or VoIP handsets, media
gateways, voice messaging servers, etc. gateways, voice messaging servers, etc.
4. EVRC-NW codec 4. EVRC-NW codec
The EVRC-NW codec operates on 20 ms frames. It produces output The EVRC-NW codec operates on 20 ms frames. It produces output
frames of one of the four different sizes: 171 bits (Rate 1), 80 bits frames of one of the four different sizes: 171 bits (Rate 1), 80 bits
(Rate 1/2), 40 bits (Rate 1/4) or 16 bits (Rate 1/8 or Rate 1/8 Non- (Rate 1/2), 40 bits (Rate 1/4) or 16 bits (Rate 1/8). In addition,
Critical). In addition, there are two zero bit codec frame types: there are two zero bit codec frame types: blank (null) frames and
blank (null) frames and erasure frames. For IP based traffic, the erasure frames. The default sampling rate is 16 kHz. Input and
Rate 1/8 Non-Critical type frame shall be suppressed and denoted as output at 8 kHz sampling rate is also supported.
blank (null) frame of 0 bit. The default sampling rate is 16 kHz.
Input and output at 8 kHz sampling rate is also supported.
The frame type values and sizes of the associated codec data frames The frame type values and sizes of the associated codec data frames
are listed in the table below: are listed in the table below:
Value Rate Total codec data frame size in bytes (and in bits) Value Rate Total codec data frame size in bytes (and in bits)
-------------------------------------------------------------------- --------------------------------------------------------------------
0 Blank(Null) 0 (0 bit) 0 Blank(Null) 0 (0 bit)
1 1/8 2 (16 bits) 1 1/8 2 (16 bits)
2 1/4 5 (40 bits) 2 1/4 5 (40 bits)
3 1/2 10 (80 bits) 3 1/2 10 (80 bits)
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