rfc8817xml2.original.xml   rfc8817.xml 
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<rfc submissionType="IETF" docName="draft-ietf-payload-tsvcis-05" category="std"
ipr="trust200902">
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<front>
<title>RTP Payload Format for TSVCIS Codec</title>
<author initials="V." surname="Demjanenko" fullname="Victor Demjanenko, P <rfc xmlns:xi="http://www.w3.org/2001/XInclude" submissionType="IETF"
h.D."> docName="draft-ietf-payload-tsvcis-05" category="std" ipr="trust200902"
<organization>VOCAL Technologies, Ltd.</organization> obsoletes="" updates="" xml:lang="en" symRefs="true" sortRefs="true"
<address> tocInclude="true" version="3" number="8817" consensus="yes">
<postal>
<street>520 Lee Entrance</street>
<street>Suite 202</street>
<city>Buffalo</city><region>NY</region><code>14228</code>
<country>United States of America</country>
</postal>
<phone>+1 716 688 4675</phone>
<email>victor.demjanenko@vocal.com</email>
</address>
</author>
<author initials="J." surname="Punaro" fullname="John Punaro"> <!-- xml2rfc v2v3 conversion 2.46.0 -->
<organization>VOCAL Technologies, Ltd.</organization> <!-- Generated by id2xml 1.5.0 on 2020-07-02T22:03:45Z -->
<address> <front>
<postal>
<street>520 Lee Entrance</street>
<street>Suite 202</street>
<city>Buffalo</city><region>NY</region><code>14228</code>
<country>United States of America</country>
</postal>
<phone>+1 716 688 4675</phone>
<email>john.punaro@vocal.com</email>
</address>
</author>
<author initials="D." surname="Satterlee" fullname="David Satterlee"> <title abbrev="RTP Payload Format for TSVCIS Codec">RTP Payload Format for
<organization>VOCAL Technologies, Ltd.</organization> Tactical Secure Voice Cryptographic Interoperability Specification
<address> (TSVCIS) Codec</title>
<postal> <seriesInfo name="RFC" value="8817"/>
<street>520 Lee Entrance</street> <author initials="V." surname="Demjanenko" fullname="Victor Demjanenko, Ph.D
<street>Suite 202</street> .">
<city>Buffalo</city><region>NY</region><code>14228</code> <organization>VOCAL Technologies, Ltd.</organization>
<country>United States of America</country> <address>
</postal> <postal>
<phone>+1 716 688 4675</phone> <street>520 Lee Entrance, Suite 202</street>
<email>david.satterlee@vocal.com</email> <city>Buffalo</city>
</address> <region>NY</region>
</author> <code>14228</code>
<country>United States of America</country>
</postal>
<phone>+1 716 688 4675</phone>
<email>victor.demjanenko@vocal.com</email>
</address>
</author>
<author initials="J." surname="Punaro" fullname="John Punaro">
<organization>VOCAL Technologies, Ltd.</organization>
<address>
<postal>
<street>520 Lee Entrance, Suite 202</street>
<city>Buffalo</city>
<region>NY</region>
<code>14228</code>
<country>United States of America</country>
</postal>
<phone>+1 716 688 4675</phone>
<email>john.punaro@vocal.com</email>
</address>
</author>
<author initials="D." surname="Satterlee" fullname="David Satterlee">
<organization>VOCAL Technologies, Ltd.</organization>
<address>
<postal>
<street>520 Lee Entrance, Suite 202</street>
<city>Buffalo</city>
<region>NY</region>
<code>14228</code>
<country>United States of America</country>
</postal>
<phone>+1 716 688 4675</phone>
<email>david.satterlee@vocal.com</email>
</address>
</author>
<date year="2020" month="August"/>
<workgroup>Payload Working Group</workgroup>
<date year="2020" month="July"/> <keyword>MELP</keyword>
<workgroup>Payload Working Group</workgroup> <keyword>MELPe</keyword>
<abstract><t> <keyword>TSVCIS</keyword>
<keyword>NRLVDR</keyword>
<keyword>Naval Research Laboratory</keyword>
<keyword>NRL</keyword>
<keyword>NATO</keyword>
<keyword>TSVWG</keyword>
<keyword>Department of Defense</keyword>
<keyword>DoD</keyword>
<keyword>NSA</keyword>
<keyword>MIL-STD</keyword>
<abstract>
<t>
This document describes the RTP payload format for the Tactical This document describes the RTP payload format for the Tactical
Secure Voice Cryptographic Interoperability Specification (TSVCIS) Secure Voice Cryptographic Interoperability Specification (TSVCIS)
speech coder. TSVCIS is a scalable narrowband voice coder supporting speech coder. TSVCIS is a scalable narrowband voice coder supporting
varying encoder data rates and fallbacks. It is implemented as an varying encoder data rates and fallbacks. It is implemented as an
augmentation to the Mixed Excitation Linear Prediction Enhanced augmentation to the Mixed Excitation Linear Prediction Enhanced
(MELPe) speech coder by conveying additional speech coder parameters (MELPe) speech coder by conveying additional speech coder parameters
for enhancing voice quality. TSVCIS augmented speech data is to enhance voice quality. TSVCIS augmented speech data is
processed in conjunction with its temporal matched MELP 2400 speech processed in conjunction with its temporally matched Mixed Excitation Linear
data. The RTP packetization of TSVCIS and MELPe speech coder data is Prediction (MELP) 2400 speech data. The RTP packetization of TSVCIS and
described in detail.</t> MELPe speech coder data is described in detail.</t>
</abstract>
</abstract> </front>
</front> <middle>
<section anchor="sect-1" numbered="true" toc="default">
<middle> <name>Introduction</name>
<section title="Introduction" anchor="sect-1"><t> <t>
This document describes how compressed Tactical Secure Voice This document describes how compressed Tactical Secure Voice
Cryptographic Interoperability Specification (TSVCIS) speech as Cryptographic Interoperability Specification (TSVCIS) speech as
produced by the TSVCIS codec <xref target="TSVCIS"/> <xref target="NRLVDR"/> produced by the TSVCIS codec <xref target="TSVCIS" format="default"/> <xref t
may be formatted for arget="NRLVDR" format="default"/> may be formatted for
use as an RTP payload. The TSVCIS speech coder (or TSVCIS speech use as an RTP payload. The TSVCIS speech coder (or TSVCIS speech-aware commu
aware communications equipment on any intervening transport link) may nications equipment on any intervening transport link) may
adjust to restricted bandwidth conditions by reducing the amount of adjust to restricted bandwidth conditions by reducing the amount of
augmented speech data and relying on the underlying MELPe speech augmented speech data and relying on the underlying MELPe speech
coder for the most constrained bandwidth links.</t> coder for the most constrained bandwidth links.</t>
<t>
<t>
Details are provided for packetizing the TSVCIS augmented speech data Details are provided for packetizing the TSVCIS augmented speech data
along with MELPe 2400 bps speech parameters in a RTP packet. The along with MELPe 2400 bps speech parameters in an RTP packet. The
sender may send one or more codec data frames per packet, depending sender may send one or more codec data frames per packet, depending
on the application scenario or based on transport network conditions, on the application scenario or based on transport network conditions,
bandwidth restrictions, delay requirements, and packet loss bandwidth restrictions, delay requirements, and packet loss
tolerance.</t> tolerance.</t>
<section anchor="sect-1.1" numbered="true" toc="default">
<section title="Conventions" anchor="sect-1.1"><t> <name>Conventions</name>
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", <t>
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
"OPTIONAL" in this document are to be interpreted as described in "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>
BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, ",
they appear in all "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>",
capitals, as shown here.</t> "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document are to
<t> be interpreted as
described in BCP&nbsp;14 <xref target="RFC2119"/> <xref target="RFC8174"/>
when, and only when, they appear in all capitals, as shown here.
</t>
<t>
Best current practices for writing an RTP payload format Best current practices for writing an RTP payload format
specification were followed <xref target="RFC2736"/> <xref target="RFC8088"/> specification were followed <xref target="RFC2736" format="default"/> <xref t
.</t> arget="RFC8088" format="default"/>.</t>
</section>
</section>
</section> <section anchor="sect-1.2" numbered="true" toc="default">
<name>Abbreviations</name>
<t>The following abbreviations are used in this document.</t>
<dl newline="false" indent="10" spacing="normal">
<dt>AVP:</dt><dd>Audio/Video Profile</dd>
<dt>AVPF:</dt><dd>Audio/Video Profile Feedback</dd>
<dt>CELP:</dt><dd>Code-Excited Linear Prediction</dd>
<dt>FEC:</dt><dd>Forward Error Correction</dd>
<dt>LPC:</dt><dd>Linear-Predictive Coding</dd>
<dt>LSB:</dt><dd>Least Significant Bit</dd>
<dt>MELP:</dt><dd>Mixed Excitation Linear Prediction</dd>
<dt>MELPe:</dt><dd>Mixed Excitation Linear Prediction Enhanced</dd>
<dt>MSB:</dt><dd>Most Significant Bit</dd>
<dt>MTC:</dt><dd>Modified Count</dd>
<dt>NATO:</dt><dd>North American Treaty Organization</dd>
<dt>NRL:</dt><dd>Naval Research Lab</dd>
<dt>PLC:</dt><dd>Packet Loss Concealment</dd>
<dt>SAVP:</dt><dd>Secure Audio/Video Profile</dd>
<dt>SAVPF:</dt><dd>Secure Audio/Video Profile Feedback</dd>
<dt>SDP:</dt><dd>Session Description Protocol</dd>
<dt>SSRC:</dt><dd>Synchronization Source</dd>
<dt>SRTP:</dt><dd>Secure Real-Time Transport Protocol</dd>
<dt>TSVCIS:</dt><dd>Tactical Secure Voice Cryptographic Interoperability Specifi
cation</dd>
<dt>VAD:</dt><dd>Voice Activity Detect</dd>
<dt>VDR:</dt><dd>Variable Date Rate</dd>
</dl>
<section title="Background" anchor="sect-2"><t> </section>
</section>
<section anchor="sect-2" numbered="true" toc="default">
<name>Background</name>
<t>
The MELP speech coder was developed by the US military as an upgrade The MELP speech coder was developed by the US military as an upgrade
from the LPC-based CELP standard vocoder for low-bitrate from the LPC-based CELP standard vocoder for low-bitrate
communications <xref target="MELP"/>. ("LPC" stands for "Linear-Predictive C oding", communications <xref target="MELP" format="default"/>. ("LPC" stands for "Li near-Predictive Coding",
and "CELP" stands for "Code-Excited Linear Prediction".) MELP was and "CELP" stands for "Code-Excited Linear Prediction".) MELP was
further enhanced and subsequently adopted by NATO as MELPe for use by further enhanced and subsequently adopted by NATO as "MELPe" for use by
its members and Partnership for Peace countries for military and its members and Partnership for Peace countries for military and
other governmental communications as international NATO Standard other governmental communications as international NATO Standard
STANAG 4591 <xref target="MELPE"/>.</t> STANAG 4591 <xref target="MELPE" format="default"/>.</t>
<t>
<t>
The Tactical Secure Voice Cryptographic Interoperability The Tactical Secure Voice Cryptographic Interoperability
Specification (TSVCIS) is a specification written by the Tactical Specification (TSVCIS) is a specification written by the Tactical
Secure Voice Working Group (TSVWG) for enabling all modern tactical Secure Voice Working Group (TSVWG) to enable all modern tactical
secure voice devices to be interoperable across the Department of secure voice devices to be interoperable across the US Department of
Defense <xref target="TSVCIS"/>. One of the most important aspects is that t Defense <xref target="TSVCIS" format="default"/>. One of the most important
he aspects is that the
voice modes defined in TSVCIS are based on specific fixed rates of voice modes defined in TSVCIS are based on specific fixed rates of the Naval
Naval Research Lab's (NRL's) Variable Date Rate (VDR) Vocoder which Research Lab's (NRL's) Variable Date Rate (VDR) Vocoder, which
uses the MELPe standard as its base <xref target="NRLVDR"/>. A complete TSVC uses the MELPe standard as its base <xref target="NRLVDR" format="default"/>.
IS A complete TSVCIS
speech frame consists of MELPe speech parameters and corresponding speech frame consists of MELPe speech parameters and corresponding
TSVCIS augmented speech data.</t> TSVCIS augmented speech data.</t>
<t>
<t>
In addition to the augmented speech data, the TSVCIS specification In addition to the augmented speech data, the TSVCIS specification
identifies which speech coder and framing bits are to be encrypted, identifies which speech coder and framing bits are to be encrypted
and how they are protected by forward error correction (FEC) and how they are protected by forward error correction (FEC)
techniques (using block codes). At the RTP transport layer, only the techniques (using block codes). At the RTP transport layer, only the
speech-coder-related bits need to be considered and are conveyed in speech coder-related bits need to be considered and are conveyed in
unencrypted form. In most IP-based network deployments, standard unencrypted form. In most IP-based network deployments, standard
link encryption methods (SRTP, VPNs, FIPS 140 link encryptors or Type link encryption methods (Secure Real-Time Transport Protocol (SRTP), VPNs, FI PS 140 link encryptors, or Type
1 Ethernet encryptors) would be used to secure the RTP speech 1 Ethernet encryptors) would be used to secure the RTP speech
contents.</t> contents.</t>
<t> <t>
TSVCIS augmented speech data is derived from the signal processing TSVCIS augmented speech data is derived from the signal processing
and data already performed by the MELPe speech coder. For the and data generated by the MELPe speech coder. For the
purposes of this specification, only the general parameter nature of purposes of this specification, only the general parameter nature of
TSVCIS will be characterized. Depending on the bandwidth available TSVCIS will be characterized. Depending on the bandwidth available
(and FEC requirements), a varying number of TSVCIS-specific speech (and FEC requirements), a varying number of TSVCIS-specific speech
coder parameters need to be transported. These are first byte-packed coder parameters need to be transported. These are first byte-packed
and then conveyed from encoder to decoder.</t> and then conveyed from encoder to decoder.</t>
<t>
<t>
Byte packing of TSVCIS speech data into packed parameters is Byte packing of TSVCIS speech data into packed parameters is
processed as per the following example:</t> processed as per the following example, where</t>
<dl><dt>Three-bit field:</dt><dd>Bits A, B, and C (A is MSB; C is LSB)</dd>
<figure><artwork><![CDATA[ <dt>Five-bit field:</dt><dd>Bits D, E, F, G, and H (D is MSB; H is LSB)</dd
Three-bit field: bits A, B, and C (A is MSB, C is LSB) >
Five-bit field: bits D, E, F, G, and H (D is MSB, H is LSB) </dl>
<artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| H | G | F | E | D | C | B | A | | H | G | F | E | D | C | B | A |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> <t>
<t>
This packing method places the three-bit field "first" in the lowest This packing method places the three-bit field "first" in the lowest
bits followed by the next five-bit field. Parameters may be split bits followed by the next five-bit field. Parameters may be split
between octets with the most significant bits in the earlier octet. between octets with the most significant bits in the earlier octet.
Any unfilled bits in the last octet MUST be filled with zero.</t> Any unfilled bits in the last octet <bcp14>MUST</bcp14> be filled with
zero.</t>
<t> <t>
In order to accommodate a varying amount of TSVCIS augmented speech In order to accommodate a varying amount of TSVCIS augmented speech
data, an octet count specifies the number of octets representing data, an octet count specifies the number of octets representing
the packed TSVCIS parameters. The encoding to do so is presented in the TSVCIS packed parameters. The encoding to do so is presented in
<xref target="sect-3.2"/>. TSVCIS specifically uses the NRL VDR in two <xref target="sect-3.2" format="default"/>. TSVCIS specifically uses the NRL
configurations using a fixed set of 15 and 35 packed octet VDR in two
parameters in a standardized order <xref target="TSVCIS"/>.</t> configurations with a fixed set of 15 and 35 packed octet
parameters in a standardized order <xref target="TSVCIS" format="default"/>.<
</section> /t>
</section>
<section title="Payload Format" anchor="sect-3"><t> <section anchor="sect-3" numbered="true" toc="default">
The TSVCIS codec augments the standard MELP 2400, 1200 and 600 <name>Payload Format</name>
<t>
The TSVCIS codec augments the standard MELP 2400, 1200, and 600
bitrates and hence uses 22.5, 67.5, or 90 ms frames with a sampling bitrates and hence uses 22.5, 67.5, or 90 ms frames with a sampling
rate clock of 8 kHz, so the RTP timestamp MUST be in units of 1/8000 rate clock of 8 kHz, so the RTP timestamp <bcp14>MUST</bcp14> be in units of 1/8000
of a second.</t> of a second.</t>
<t>
<t> The RTP payload for TSVCIS has the format shown in <xref target="fig-1"/>. N
The RTP payload for TSVCIS has the format shown in Figure 1. No o
additional header specific to this payload format is needed. This additional header specific to this payload format is needed. This
format is intended for situations where the sender and the receiver format is intended for situations where the sender and the receiver
send one or more codec data frames per packet.</t> send one or more codec data frames per packet.</t>
<figure anchor="fig-1">
<figure title="Packet Format Diagram" anchor="fig-1"><artwork><![CDATA[ <name>Packet Format Diagram</name>
0 1 2 3 <artwork name="" type="" align="left" alt=""><![CDATA[
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RTP Header | | RTP Header |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| | | |
+ one or more frames of TSVCIS | + one or more frames of TSVCIS |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork> ]]></artwork>
</figure> </figure>
<t> <t>
The RTP header of the packetized encoded TSVCIS speech has the The RTP header of the packetized encoded TSVCIS speech has the
expected values as described in <xref target="RFC3550"/>. The usage of the M expected values as described in <xref target="RFC3550" format="default"/>. T
bit he usage of the M bit
SHOULD be as specified in the applicable RTP profile -- for example, <bcp14>SHOULD</bcp14> be as specified in the applicable RTP profile -- for ex
<xref target="RFC3551"/>, where <xref target="RFC3551"/> specifies that if th ample,
e sender does not <xref target="RFC3551" format="default"/> specifies that if the sender does n
ot
suppress silence (i.e., sends a frame on every frame interval), the suppress silence (i.e., sends a frame on every frame interval), the
M bit will always be zero. When more than one codec data frame is M bit will always be zero. When more than one codec data frame is
present in a single RTP packet, the timestamp specified is that of present in a single RTP packet, the timestamp specified is that of
the oldest data frame represented in the RTP packet.</t> the oldest data frame represented in the RTP packet.</t>
<t>
<t>
The assignment of an RTP payload type for this new packet format is The assignment of an RTP payload type for this new packet format is
outside the scope of this document and will not be specified here. It outside the scope of this document and will not be specified here. It
is expected that the RTP profile for a particular class of is expected that the RTP profile for a particular class of
applications will assign a payload type for this encoding, or if that applications will assign a payload type for this encoding; if that
is not done, then a payload type in the dynamic range shall be chosen is not done, then a payload type in the dynamic range shall be chosen
by the sender.</t> by the sender.</t>
<section anchor="sect-3.1" numbered="true" toc="default">
<section title="MELPe Bitstream Definitions" anchor="sect-3.1"><t> <name>MELPe Bitstream Definitions</name>
The TCVCIS speech coder includes all three MELPe coder rates used as <t>
base speech parameters or as speech coders for bandwidth restricted The TSVCIS speech coder includes all three MELPe coder rates used as
links. RTP packetization of MELPe follows RFC 8130 and is repeated base speech parameters or as speech coders for bandwidth-restricted
here for all three MELPe rates <xref target="RFC8130"/> with its recommendati links. RTP packetization of MELPe follows <xref target="RFC8130"/> and is re
ons now peated
here for all three MELPe rates <xref target="RFC8130" format="default"/>, wit
h its recommendations now
regarded as requirements. The bits previously labeled as RSVA, RSVB, regarded as requirements. The bits previously labeled as RSVA, RSVB,
and RSVC in RFC 8130 SHOULD be filled with rate coding, CODA, CODB, and RSVC in <xref target="RFC8130"/> <bcp14>SHOULD</bcp14> be filled with
and CODC, as shown in Table 1 (compatible with Table 7 in Section 3.3 rate code bits CODA, CODB,
of <xref target="RFC8130"/>).</t> and CODC, as shown in <xref target="tab-1"/> (compatible with Table 7 in <xre
f target="RFC8130" sectionFormat="of" section="3.3"/>).</t>
<texttable title="TSVCIS/MELPe Frame Bitrate Indicators and Frame Length" <table anchor="tab-1" align="center">
anchor="tab-1" style="all"><ttcol> Coder Bitrate</ttcol> <name>TSVCIS/MELPe Frame Bitrate Indicators and Frame Length</name>
<ttcol> CODA</ttcol> <thead>
<ttcol> CODB</ttcol> <tr>
<ttcol> CODC</ttcol> <th align="left">Coder Bitrate</th>
<ttcol> Length</ttcol> <th align="left">CODA</th>
<c>2400 bps</c> <th align="left">CODB</th>
<c>0</c> <th align="left">CODC</th>
<c>0</c> <th align="left">Length</th>
<c>N/A</c> </tr>
<c>7</c> </thead>
<c>1200 bps</c> <tbody>
<c>1</c> <tr>
<c>0</c> <td align="left">2400 bps</td>
<c>0</c> <td align="left">0</td>
<c>11</c> <td align="left">0</td>
<c>600 bps</c> <td align="left">N/A</td>
<c>0</c> <td align="left">7</td>
<c>1</c> </tr>
<c>N/A</c> <tr>
<c>7</c> <td align="left">1200 bps</td>
<c>Comfort Noise</c> <td align="left">1</td>
<c>1</c> <td align="left">0</td>
<c>0</c> <td align="left">0</td>
<c>1</c> <td align="left">11</td>
<c>2</c> </tr>
<c>TSVCIS data</c> <tr>
<c>1</c> <td align="left">600 bps</td>
<c>1</c> <td align="left">0</td>
<c>N/A</c> <td align="left">1</td>
<c>var.</c> <td align="left">N/A</td>
</texttable> <td align="left">7</td>
<t> </tr>
<tr>
<td align="left">Comfort Noise</td>
<td align="left">1</td>
<td align="left">0</td>
<td align="left">1</td>
<td align="left">2</td>
</tr>
<tr>
<td align="left">TSVCIS Data</td>
<td align="left">1</td>
<td align="left">1</td>
<td align="left">N/A</td>
<td align="left">var.</td>
</tr>
</tbody>
</table>
<t>
The total number of bits used to describe one MELPe frame of 2400 bps The total number of bits used to describe one MELPe frame of 2400 bps
speech is 54, which fits in 7 octets (with two rate code bits). For speech is 54, which fits in 7 octets (with two rate code bits). For
MELPe 1200 bps speech, the total number of bits used is 81, which MELPe 1200 bps speech, the total number of bits used is 81, which
fits in 11 octets (with three rate code bits and four unused bits). fits in 11 octets (with three rate code bits and four unused bits).
For MELPe 600 bps speech, the total number of bits used is 54, which For MELPe 600 bps speech, the total number of bits used is 54, which
fits in 7 octets (with two rate code bits). The comfort noise frame fits in 7 octets (with two rate code bits). The comfort noise frame
consists of 13 bits, which fits in 2 octets (with three rate code consists of 13 bits, which fits in 2 octets (with three rate code
bits). TSVCIS packed parameters will use the last code combination bits). TSVCIS packed parameters will use the last code combination
in a trailing byte as discussed in <xref target="sect-3.2"/>.</t> in a trailing byte as discussed in <xref target="sect-3.2" format="default"/>
.</t>
<t> <t>
It should be noted that CODB for MELPe 600 bps mode MAY deviate from It should be noted that CODB for MELPe 600 bps mode <bcp14>MAY</bcp14> deviat
the value in Table 1 when bit 55 is used as an alternating 1/0 e from
the value in <xref target="tab-1"/> when bit 55 is used as an alternating 1/0
end-to-end framing bit. Frame decoding would remain distinct as CODA end-to-end framing bit. Frame decoding would remain distinct as CODA
being zero on its own would indicate a 7-byte frame for either 2400 being zero on its own would indicate a 7-byte frame for either a 2400
or 600 bps rate and the use of 600 bps speech coding could be deduced or 600 bps rate, and the use of 600 bps speech coding could be deduced
from the RTP timestamp (and anticipated by the SDP negotiations).</t> from the RTP timestamp (and anticipated by the Session Description Protocol
(SDP) negotiations).</t>
<section title="2400 bps Bitstream Structure" anchor="sect-3.1.1"><t> <section anchor="sect-3.1.1" numbered="true" toc="default">
The 2400 bps MELPe RTP payload is constructed as per Figure 2. Note <name>2400 bps Bitstream Structure</name>
that CODA MUST be filled with 0 and CODB SHOULD be filled with 0 as <t>
per <xref target="sect-3.1"/>. CODB MAY contain an end-to-end framing bit if The 2400 bps MELPe RTP payload is constructed as per <xref target="fig-2"/>.
Note
that CODA <bcp14>MUST</bcp14> be filled with 0 and CODB <bcp14>SHOULD</bcp14>
be filled with 0 as
per <xref target="sect-3.1" format="default"/>. CODB <bcp14>MAY</bcp14> cont
ain an end-to-end framing bit if
required by the endpoints.</t> required by the endpoints.</t>
<figure anchor="fig-2">
<figure title="Packed MELPe 2400 bps Payload Octets" anchor="fig-2"><artw <name>Packed MELPe 2400 bps Payload Octets</name>
ork><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 | | B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_16 | B_15 | B_14 | B_13 | B_12 | B_11 | B_10 | B_09 | | B_16 | B_15 | B_14 | B_13 | B_12 | B_11 | B_10 | B_09 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_24 | B_23 | B_22 | B_21 | B_20 | B_19 | B_18 | B_17 | | B_24 | B_23 | B_22 | B_21 | B_20 | B_19 | B_18 | B_17 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_32 | B_31 | B_30 | B_29 | B_28 | B_27 | B_26 | B_25 | | B_32 | B_31 | B_30 | B_29 | B_28 | B_27 | B_26 | B_25 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_40 | B_39 | B_38 | B_37 | B_36 | B_35 | B_34 | B_33 | | B_40 | B_39 | B_38 | B_37 | B_36 | B_35 | B_34 | B_33 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_48 | B_47 | B_46 | B_45 | B_44 | B_43 | B_42 | B_41 | | B_48 | B_47 | B_46 | B_45 | B_44 | B_43 | B_42 | B_41 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| CODA | CODB | B_54 | B_53 | B_52 | B_51 | B_50 | B_49 | | CODA | CODB | B_54 | B_53 | B_52 | B_51 | B_50 | B_49 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> </figure>
</section> </section>
<section anchor="sect-3.1.2" numbered="true" toc="default">
<section title="1200 bps Bitstream Structure" anchor="sect-3.1.2"><t> <name>1200 bps Bitstream Structure</name>
The 1200 bps MELPe RTP payload is constructed as per Figure 3. Note <t>
that CODA, CODB, and CODC MUST be filled with 1, 0, and 0 The 1200 bps MELPe RTP payload is constructed as per <xref target="fig-3"/>.
respectively as per <xref target="sect-3.1"/>. RSV0 MUST be coded as 0.</t> Note
that CODA, CODB, and CODC <bcp14>MUST</bcp14> be filled with 1, 0, and 0,
<figure title="Packed MELPe 1200 bps Payload Octets" anchor="fig-3"><artw respectively, as per <xref target="sect-3.1" format="default"/>. RSV0 <bcp14
ork><![CDATA[ >MUST</bcp14> be coded as 0.</t>
<figure anchor="fig-3">
<name>Packed MELPe 1200 bps Payload Octets</name>
<artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 | | B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_16 | B_15 | B_14 | B_13 | B_12 | B_11 | B_10 | B_09 | | B_16 | B_15 | B_14 | B_13 | B_12 | B_11 | B_10 | B_09 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_24 | B_23 | B_22 | B_21 | B_20 | B_19 | B_18 | B_17 | | B_24 | B_23 | B_22 | B_21 | B_20 | B_19 | B_18 | B_17 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_32 | B_31 | B_30 | B_29 | B_28 | B_27 | B_26 | B_25 | | B_32 | B_31 | B_30 | B_29 | B_28 | B_27 | B_26 | B_25 |
skipping to change at line 363 skipping to change at line 405
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_64 | B_63 | B_62 | B_61 | B_60 | B_59 | B_58 | B_57 | | B_64 | B_63 | B_62 | B_61 | B_60 | B_59 | B_58 | B_57 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_72 | B_71 | B_70 | B_69 | B_68 | B_67 | B_66 | B_65 | | B_72 | B_71 | B_70 | B_69 | B_68 | B_67 | B_66 | B_65 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_80 | B_79 | B_78 | B_77 | B_76 | B_75 | B_74 | B_73 | | B_80 | B_79 | B_78 | B_77 | B_76 | B_75 | B_74 | B_73 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| CODA | CODB | CODC | RSV0 | RSV0 | RSV0 | RSV0 | B_81 | | CODA | CODB | CODC | RSV0 | RSV0 | RSV0 | RSV0 | B_81 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> </figure>
</section> </section>
<section anchor="sect-3.1.3" numbered="true" toc="default">
<section title="600 bps Bitstream Structure" anchor="sect-3.1.3"><t> <name>600 bps Bitstream Structure</name>
The 600 bps MELPe RTP payload is constructed as per Figure 4. Note <t>
CODA MUST be filled with 0 and CODB SHOULD be filled with 1 as per The 600 bps MELPe RTP payload is constructed as per <xref target="fig-4"/>.
<xref target="sect-3.1"/>. CODB MAY contain an end-to-end framing bit if req Note
uired CODA <bcp14>MUST</bcp14> be filled with 0 and CODB <bcp14>SHOULD</bcp14> be f
illed with 1 as per
<xref target="sect-3.1" format="default"/>. CODB <bcp14>MAY</bcp14> contain
an end-to-end framing bit if required
by the endpoints.</t> by the endpoints.</t>
<figure anchor="fig-4">
<figure title="Packed MELPe 600 bps Payload Octets" anchor="fig-4"><artwo <name>Packed MELPe 600 bps Payload Octets</name>
rk><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 | | B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_16 | B_15 | B_14 | B_13 | B_12 | B_11 | B_10 | B_09 | | B_16 | B_15 | B_14 | B_13 | B_12 | B_11 | B_10 | B_09 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_24 | B_23 | B_22 | B_21 | B_20 | B_19 | B_18 | B_17 | | B_24 | B_23 | B_22 | B_21 | B_20 | B_19 | B_18 | B_17 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_32 | B_31 | B_30 | B_29 | B_28 | B_27 | B_26 | B_25 | | B_32 | B_31 | B_30 | B_29 | B_28 | B_27 | B_26 | B_25 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_40 | B_39 | B_38 | B_37 | B_36 | B_35 | B_34 | B_33 | | B_40 | B_39 | B_38 | B_37 | B_36 | B_35 | B_34 | B_33 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_48 | B_47 | B_46 | B_45 | B_44 | B_43 | B_42 | B_41 | | B_48 | B_47 | B_46 | B_45 | B_44 | B_43 | B_42 | B_41 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| CODA | CODB | B_54 | B_53 | B_52 | B_51 | B_50 | B_49 | | CODA | CODB | B_54 | B_53 | B_52 | B_51 | B_50 | B_49 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> </figure>
</section> </section>
<section anchor="sect-3.1.4" numbered="true" toc="default">
<section title="Comfort Noise Bitstream Definition" anchor="sect-3.1.4">< <name>Comfort Noise Bitstream Definition</name>
t> <t>
The comfort noise MELPe RTP payload is constructed as per Figure 5. The comfort noise MELPe RTP payload is constructed as per <xref target="fig-5
Note that CODA, CODB, and CODC MUST be filled with 1, 0, and 1 "/>.
respectively as per <xref target="sect-3.1"/>.</t> Note that CODA, CODB, and CODC <bcp14>MUST</bcp14> be filled with 1, 0, and 1
,
<figure title="Packed MELPe Comfort Noise Payload Octets" anchor="fig-5"> respectively, as per <xref target="sect-3.1" format="default"/>.</t>
<artwork><![CDATA[ <figure anchor="fig-5">
<name>Packed MELPe Comfort Noise Payload Octets</name>
<artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 | | B_08 | B_07 | B_06 | B_05 | B_04 | B_03 | B_02 | B_01 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| CODA | CODB | CODC | B_13 | B_12 | B_11 | B_10 | B_09 | | CODA | CODB | CODC | B_13 | B_12 | B_11 | B_10 | B_09 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> </figure>
</section> </section>
</section>
</section> <section anchor="sect-3.2" numbered="true" toc="default">
<name>TSVCIS Bitstream Definition</name>
<section title="TSVCIS Bitstream Definition" anchor="sect-3.2"><t> <t>
The TSVCIS augmented speech data as packed parameters MUST be placed The TSVCIS augmented speech data as packed parameters <bcp14>MUST</bcp14> be
placed
immediately after a corresponding MELPe 2400 bps payload in the same immediately after a corresponding MELPe 2400 bps payload in the same
RTP packet. The packed parameters are counted in octets (TC). The RTP packet. The packed parameters are counted in octets (TC). The
preferred placement SHOULD be used for TSVCIS payloads with TC less preferred placement <bcp14>SHOULD</bcp14> be used for TSVCIS payloads with TC
than or equal to 77 octets, and is shown in Figure 6. In the less
preferred placement, a single trailing octet SHALL be appended to than or equal to 77 octets; this is shown in <xref target="fig-6"/>. In the
include a two-bit rate code, CODA and CODB, (both bits set to one) preferred placement, a single trailing octet <bcp14>SHALL</bcp14> be appended
to
include a two-bit rate code, CODA and CODB (both bits set to one),
and a six-bit modified count (MTC). The special modified count value and a six-bit modified count (MTC). The special modified count value
of all ones (representing a MTC value of 63) SHALL NOT be used for of all ones (representing an MTC value of 63) <bcp14>SHALL NOT</bcp14> be use d for
this format as it is used as the indicator for the alternate packing this format as it is used as the indicator for the alternate packing
format shown next. In a standard implementation, the TSVCIS speech format shown next. In a standard implementation, the TSVCIS speech
coder uses a minimum of 15 octets for parameters in octet packed coder uses a minimum of 15 octets for parameters in octet packed
form. The modified count (MTC) MUST be reduced by 15 from the full form. The modified count (MTC) <bcp14>MUST</bcp14> be reduced by 15 from the full
octet count (TC). Computed MTC = TC-15. This accommodates a maximum octet count (TC). Computed MTC = TC-15. This accommodates a maximum
of 77 parameter octets (maximum value of MTC is 62, 77 is the sum of of 77 parameter octets (the maximum value of MTC is 62; 77 is the sum of
62+15).</t> 62+15).</t>
<figure anchor="fig-6">
<figure title="Preferred Packed TSVCIS Payload Octets" anchor="fig-6"><ar <name>Preferred Packed TSVCIS Payload Octets</name>
twork><![CDATA[ <artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
1 | T008 | T007 | T006 | T005 | T004 | T003 | T002 | T001 | 1 | T008 | T007 | T006 | T005 | T004 | T003 | T002 | T001 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
2 | T016 | T015 | T014 | T013 | T012 | T011 | T010 | T009 | 2 | T016 | T015 | T014 | T013 | T012 | T011 | T010 | T009 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
3 | T024 | T023 | T022 | T021 | T020 | T019 | T018 | T017 | 3 | T024 | T023 | T022 | T021 | T020 | T019 | T018 | T017 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
4 | T032 | T031 | T030 | T029 | T028 | T027 | T026 | T025 | 4 | T032 | T031 | T030 | T029 | T028 | T027 | T026 | T025 |
skipping to change at line 470 skipping to change at line 517
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
14 | T112 | T111 | T110 | T109 | T108 | T107 | T106 | T105 | 14 | T112 | T111 | T110 | T109 | T108 | T107 | T106 | T105 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
15 | T120 | T119 | T118 | T117 | T116 | T115 | T114 | T113 | 15 | T120 | T119 | T118 | T117 | T116 | T115 | T114 | T113 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| . . . . | | . . . . |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
TC+1 | CODA | CODB | modified octet count | TC+1 | CODA | CODB | modified octet count |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> </figure>
<t> <t>
In order to accommodate all other NRL VDR configurations, an In order to accommodate all other NRL VDR configurations, an
alternate parameter placement MUST use two trailing bytes as shown in alternate parameter placement <bcp14>MUST</bcp14> use two trailing bytes as s
Figure 7. The last trailing byte MUST be filled with a two-bit rate hown in
code, CODA and CODB, (both bits set to one) and its six-bit count <xref target="fig-7"/>. The last trailing byte <bcp14>MUST</bcp14> be filled
field MUST be filled with ones. The second to last trailing byte with a two-bit rate
MUST contain the parameter count (TC) in octets (a value from 1 and code, CODA and CODB (both bits set to one), and its six-bit count
255, inclusive). The value of zero SHALL be considered as reserved.</t> field <bcp14>MUST</bcp14> be filled with ones. The second to last trailing b
yte
<figure title="Length Unrestricted Packed TSVCIS Payload Octets" anchor=" <bcp14>MUST</bcp14> contain the parameter count (TC) in octets (a value from
fig-7"><artwork><![CDATA[ 1 and
255, inclusive). The value of zero <bcp14>SHALL</bcp14> be considered as rese
rved.</t>
<figure anchor="fig-7">
<name>Length Unrestricted Packed TSVCIS Payload Octets</name>
<artwork name="" type="" align="left" alt=""><![CDATA[
MSB LSB MSB LSB
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
1 | T008 | T007 | T006 | T005 | T004 | T003 | T002 | T001 | 1 | T008 | T007 | T006 | T005 | T004 | T003 | T002 | T001 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
2 | T016 | T015 | T014 | T013 | T012 | T011 | T010 | T009 | 2 | T016 | T015 | T014 | T013 | T012 | T011 | T010 | T009 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
| . . . . | | . . . . |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
TC+1 | octet count | TC+1 | octet count |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
TC+2 | CODA | CODB | 1 | 1 | 1 | 1 | 1 | 1 | TC+2 | CODA | CODB | 1 | 1 | 1 | 1 | 1 | 1 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
]]></artwork> ]]></artwork>
</figure> </figure>
</section>
<section title="Multiple TSVCIS Frames in an RTP Packet" anchor="sect-3.3 </section>
"><t> <section anchor="sect-3.3" numbered="true" toc="default">
<name>Multiple TSVCIS Frames in an RTP Packet</name>
<t>
A TSVCIS RTP packet payload consists of zero or more consecutive A TSVCIS RTP packet payload consists of zero or more consecutive
TSVCIS coder frames (each consisting of MELPe 2400 and TSVCIS coder TSVCIS coder frames (each consisting of MELPe 2400 and TSVCIS coder
data), with the oldest frame first, followed by zero or one MELPe data), with the oldest frame first, followed by zero or one MELPe
comfort noise frame. The presence of a comfort noise frame can be comfort noise frame. The presence of a comfort noise frame can be
determined by its rate code bits in its last octet.</t> determined by its rate code bits in its last octet.</t>
<t>
<t>
The default packetization interval is one coder frame (22.5, 67.5, or The default packetization interval is one coder frame (22.5, 67.5, or
90 ms) according to the coder bitrate (2400, 1200, or 600 bps). For 90 ms) according to the coder bitrate (2400, 1200, or 600 bps). For
some applications, a longer packetization interval is used to reduce some applications, a longer packetization interval is used to reduce
the packet rate.</t> the packet rate.</t>
<t>
<t> A TSVCIS RTP packet without coder and comfort noise frames <bcp14>MAY</bcp14>
A TSVCIS RTP packet without coder and comfort noise frames MAY be be
used periodically by an endpoint to indicate connectivity by an used periodically by an endpoint to indicate connectivity by an
otherwise idle receiver.</t> otherwise idle receiver.</t>
<t>
<t> TSVCIS coder frames in a single RTP packet <bcp14>MAY</bcp14> have varying TS
TSVCIS coder frames in a single RTP packet MAY have varying TSVCIS VCIS
parameter octet counts. Its packed parameter octet count (length) is parameter octet counts. Its packed parameter octet count (length) is
indicated in the trailing byte(s). All MELPe frames in a single RTP indicated in the trailing byte(s). All MELPe frames in a single RTP
packet MUST be of the same coder bitrate. For all MELPe coder packet <bcp14>MUST</bcp14> be of the same coder bitrate. For all MELPe coder
frames, the coder rate bits in the trailing byte identify the frames, the coder rate bits in the trailing byte identify the
contents and length as per Table 1.</t> contents and length as per <xref target="tab-1"/>.</t>
<t>
<t>
It is important to observe that senders have the following additional It is important to observe that senders have the following additional
restrictions:</t> restrictions:</t>
<ul>
<t> <li>Senders <bcp14>SHOULD NOT</bcp14> include more TSVCIS or MELPe frames in
Senders SHOULD NOT include more TSVCIS or MELPe frames in a single a single
RTP packet than will fit in the MTU of the RTP transport protocol.</t> RTP packet than will fit in the MTU of the RTP transport protocol.</li>
<li>
<t> Frames <bcp14>MUST NOT</bcp14> be split between RTP packets.</li>
Frames MUST NOT be split between RTP packets.</t> </ul>
<t>
<t> It is <bcp14>RECOMMENDED</bcp14> that the number of frames contained within a
It is RECOMMENDED that the number of frames contained within an RTP packet n RTP packet
be consistent with the application. For example, in telephony and other be consistent with the application. For example, in telephony and other
real-time applications where delay is important, then the fewer frames per real-time applications where delay is important, the fewer frames per
packet the lower the delay, whereas for bandwidth-constrained links or packet, the lower the delay. However, for bandwidth-constrained links or
delay-insensitive streaming messaging applications, more than one frame per delay-insensitive streaming messaging applications, more than one frame per
packet or many frames per packet would be acceptable.</t> packet or many frames per packet would be acceptable.</t>
<t>
<t>
Information describing the number of frames contained in an RTP Information describing the number of frames contained in an RTP
packet is not transmitted as part of the RTP payload. The way to packet is not transmitted as part of the RTP payload. The way to
determine the number of TSVCIS/MELPe frames is to identify each frame determine the number of TSVCIS/MELPe frames is to identify each frame
type and length thereby counting the total number of octets within type and length, thereby counting the total number of octets within
the RTP packet.</t> the RTP packet.</t>
</section>
</section> <section anchor="sect-3.4" numbered="true" toc="default">
<name>Congestion Control Considerations</name>
<section title="Congestion Control Considerations" anchor="sect-3.4"><t> <t>
The target bitrate of TSVCIS can be adjusted at any point in time, The target bitrate of TSVCIS can be adjusted at any point in time,
thus allowing congestion management. Furthermore, the amount of thus allowing congestion management. Furthermore, the amount of
encoded speech or audio data encoded in a single packet can be used encoded speech or audio data encoded in a single packet can be used
for congestion control, since the packet rate is inversely for congestion control, since the packet rate is inversely
proportional to the packet duration. A lower packet transmission proportional to the packet duration. A lower packet transmission
rate reduces the amount of header overhead but at the same time rate reduces the amount of header overhead but at the same time
increases latency and loss sensitivity, so it ought to be used increases latency and loss sensitivity, so it ought to be used
with care.</t> with care.</t>
<t>
<t>
Since UDP does not provide congestion control, applications that use Since UDP does not provide congestion control, applications that use
RTP over UDP SHOULD implement their own congestion control above the RTP over UDP <bcp14>SHOULD</bcp14> implement their own congestion control abo
UDP layer <xref target="RFC8085"/> and MAY also implement a transport circuit ve the
breaker <xref target="RFC8083"/>. Work in the RMCAT working group <xref targ UDP layer <xref target="RFC8085" format="default"/> and <bcp14>MAY</bcp14> al
et="RMCAT"/> describes so implement a transport circuit
breaker <xref target="RFC8083" format="default"/>. Work in the RMCAT Working
Group <xref target="RMCAT" format="default"/> describes
the interactions and conceptual interfaces necessary between the the interactions and conceptual interfaces necessary between the
application components that relate to congestion control, including application components that relate to congestion control, including
the RTP layer, the higher-level media codec control layer, and the the RTP layer, the higher-level media codec control layer, and the
lower-level transport interface, as well as components dedicated to lower-level transport interface, as well as components dedicated to
congestion control functions.</t> congestion control functions.</t>
</section>
</section> </section>
<section anchor="sect-4" numbered="true" toc="default">
</section> <name>Payload Format Parameters</name>
<t>
<section title="Payload Format Parameters" anchor="sect-4"><t>
This RTP payload format is identified using the TSVCIS media subtype, This RTP payload format is identified using the TSVCIS media subtype,
which is registered in accordance with RFC 4855 <xref target="RFC4855"/> and which is registered in accordance with <xref target="RFC4855" format="default
per the "/> and per the
media type registration template from RFC 6838 <xref target="RFC6838"/>.</t> media type registration template from <xref target="RFC6838" format="default"
/>.</t>
<section title="Media Type Definitions" anchor="sect-4.1"><t> <section anchor="sect-4.1" numbered="true" toc="default">
<name>Media Type Definitions</name>
<list style="hanging"> <dl newline="false" spacing="normal">
<dt>Type name:</dt>
<t hangText="Type name:"> audio</t> <dd> audio</dd>
<dt>Subtype name:</dt>
<t hangText="Subtype name:"> TSVCIS</t> <dd> TSVCIS</dd>
<dt>Required parameters:</dt>
<t hangText="Required parameters:"> N/A</t> <dd>Clock Rate (Hz): 8000</dd>
</dl>
<t hangText="Optional parameters:"> <dl newline="true" spacing="normal">
<dt>Optional parameters:</dt>
<list style="hanging" hangIndent="6"> <dd>
<dl newline="true" spacing="normal">
<dt>ptime:</dt>
<dd> the recommended length of time (in milliseconds)
represented by the media in a packet. It <bcp14>SHALL</bcp14>
use the nearest rounded-up ms integer packet duration. For
TSVCIS, this corresponds to the following values: 23, 45, 68,
90, 112, 135, 156, and 180. Larger values can be used as long
as they are properly rounded. See <xref target="RFC4566"
sectionFormat="of" section="6"/>.</dd>
<t hangText="ptime:"> the recommended length of time (in milliseconds) <dt>maxptime:</dt>
represented by the media in a packet. It SHALL use the nearest <dd> the maximum length of time (in milliseconds) that can be
rounded-up ms integer packet duration. For TSVCIS, this corresponds to encapsulated in a packet. It <bcp14>SHALL</bcp14> use the
the following values: 23, 45, 68, 90, 112, 135, 156, and 180. Larger nearest rounded-up ms integer packet duration. For TSVCIS, this
values can be used as long as they are properly rounded. See Section 6 corresponds to the following values: 23, 45, 68, 90, 112, 135,
of RFC 4566 <xref target="RFC4566"/>.</t> 156, and 180. Larger values can be used as long as they are
properly rounded. See <xref target="RFC4566" sectionFormat="of"
section="6"/>.</dd>
<t hangText="maxptime:"> the maximum length of time (in milliseconds) <dt>bitrate:</dt>
that can be encapsulated in a packet. It SHALL use the nearest <dd> specifies the MELPe coder bitrates supported. Possible
rounded-up ms integer packet duration. For TSVCIS, this corresponds to values are a comma-separated list of rates from the following
the following values: 23, 45, 68, 90, 112, 135, 156, and 180. Larger set: 2400, 1200, 600. The modes are listed in order of
values can be used as long as they are properly rounded. See Section 6 preference; the first is preferred. If "bitrate" is not
of RFC 4566 <xref target="RFC4566"/>.</t> present, the fixed coder bitrate of 2400 <bcp14>MUST</bcp14> be
used. </dd>
<t hangText="bitrate:"> specifies the MELPe coder bitrates supported. <dt>tcmax:</dt>
Possible values are a comma-separated list of rates from the following <dd> specifies the TSVCIS maximum value for the TC supported or
set: 2400, 1200, 600. The modes are listed in order of preference; first desired, ranging from 1 to 255. If "tcmax" is not present, a
is preferred. If "bitrate" is not present, the fixed coder bitrate of default value of 35 is used.</dd>
2400 MUST be used. </t> <dt>Channels:</dt>
<dd>1</dd>
</dl>
</dd></dl>
<dl newline="false" spacing="normal">
<dt>Encoding considerations:</dt>
<dd> This media subtype is framed and binary; see <xref
target="RFC6838" sectionFormat="of" section="4.8"/>.</dd>
<dt>Security considerations:</dt>
<dd> Please see <xref target="sect-8"/> of RFC 8817.</dd>
<dt>Interoperability considerations:</dt>
<dd>N/A</dd>
<dt>Published specification:</dt>
<dd>
<xref target="TSVCIS" format="default"/></dd>
<dt>Applications that use this media type:</dt>
<dd>N/A</dd>
<dt>Fragment identifier considerations:</dt>
<dd>N/A</dd>
<t hangText="tcmax:"> specifies the TSVCIS maximum value for TC supported <dt>Additional information:</dt><dd>
or desired ranging from 1 to 255. If "tcmax" is not present, a default <t><br/></t>
value of 35 is used.</t> <dl spacing="compact">
<dt>Deprecated alias names for this type:</dt>
<dd>N/A</dd>
<dt>Magic number(s):</dt>
<dd>N/A</dd>
<dt>File extension(s):</dt>
<dd>N/A</dd>
<dt>Macintosh file type code(s):</dt>
<dd>N/A</dd>
</dl>
</dd>
</list> <dt>Person &amp; email address to contact for further information:</dt
>
<dd><t><br/><contact fullname="Victor Demjanenko, Ph.D."/>
&lt;victor.demjanenko@vocal.com&gt;
</t> </t>
</dd>
<t hangText="Encoding considerations:"> This media subtype is framed and bi <dt>Intended usage:</dt>
nary; see <dd>COMMON</dd>
Section 4.8 of RFC 6838 <xref target="RFC6838"/>.</t> <dt>Restrictions on usage:</dt>
<dd> The media subtype depends on RTP
<t hangText="Security considerations:"> Please see Section 8 of RFC XXXX.</ framing and hence is only defined for transfer via RTP <xref target="RFC35
t> 50" format="default"/>. Transport within other framing protocols is not
defined at this time.</dd>
<!-- [EDITOR NOTE - please replace XXXX with the RFC number of this document.] - <dt>Author:</dt>
-> <dd><t><contact fullname="Victor Demjanenko, Ph.D."/></t></dd>
<dt>Change controller:</dt>
<t hangText="Interoperability considerations:"> N/A</t> <dd> IETF; contact &lt;avt@ietf.org&gt;</dd>
<dt>Provisional registration? (standards tree only):</dt>
<t hangText="Published specification:"> <xref target="TSVCIS"/></t> <dd> No</dd>
</dl>
<t hangText="Applications that use this media type:"> N/A</t> </section>
<section anchor="sect-4.2" numbered="true" toc="default">
<t hangText="Fragment identifier considerations:"> N/A</t> <name>Mapping to SDP</name>
<t>
<t hangText="Additional information:">
<list style="hanging" hangIndent="9">
<?rfc subcompact="yes"?>
<t hangText="Clock Rate (Hz):"> 8000</t>
<t hangText="Channels:"> 1</t>
<?rfc subcompact="no"?>
</list>
</t>
<t hangText="Deprecated alias names for this type:"> N/A</t>
<t hangText="Magic number(s):"> N/A</t>
<t hangText="File extension(s):"> N/A</t>
<t hangText="Macintosh file type code(s):"> N/A</t>
<t hangText="Person &amp; email address to contact for further information:
">
<list>
<?rfc subcompact="yes"?>
<t>Victor Demjanenko, Ph.D.</t>
<t>VOCAL Technologies, Ltd.</t>
<t>520 Lee Entrance, Suite 202</t>
<t>Buffalo, NY 14228</t>
<t>United States of America</t>
<t>Phone: +1 716 688 4675</t>
<t>Email: victor.demjanenko@vocal.com</t>
<?rfc subcompact="no"?>
</list>
</t>
<t hangText="Intended usage:"> COMMON</t>
<t hangText="Restrictions on usage:"> The media subtype depends on RTP
framing and hence is only defined for transfer via RTP <xref
target="RFC3550"/>. Transport within other framing protocols is not
defined at this time.</t>
<t hangText="Author:">Victor Demjanenko</t>
<t hangText="Change controller:"> IETF, contact &lt;avt@ietf.org&gt;</t>
<t hangText="Provisional registration? (standards tree only):"> No</t>
</list>
</t>
</section>
<section title="Mapping to SDP" anchor="sect-4.2"><t>
The mapping of the above-defined payload format media subtype and its The mapping of the above-defined payload format media subtype and its
parameters SHALL be done according to Section 3 of RFC 4855 parameters <bcp14>SHALL</bcp14> be done according to <xref target="RFC4855" s
<xref target="RFC4855"/>.</t> ectionFormat="of" section="3"/>.</t>
<t>
<t>
The information carried in the media type specification has a The information carried in the media type specification has a
specific mapping to fields in the Session Description Protocol (SDP) specific mapping to fields in the Session Description Protocol (SDP)
<xref target="RFC4566"/>, which is commonly used to describe RTP sessions. W hen SDP <xref target="RFC4566" format="default"/>, which is commonly used to describe RTP sessions. When SDP
is used to specify sessions employing the TSVCIS codec, the mapping is used to specify sessions employing the TSVCIS codec, the mapping
is as follows:</t> is as follows:</t>
<ul spacing="normal">
<t><list style="symbols"><t>The media type ("audio") goes in SDP "m=" as <li>The media type ("audio") goes in SDP "m=" as the media name.</li>
the media name.</t> <li>The media subtype (payload format name) goes in SDP "a=rtpmap" as
the encoding name.</li>
<t>The media subtype (payload format name) goes in SDP "a=rtpmap" as <li>The parameter "bitrate" goes in the SDP "a=fmtp" attribute by
the encoding name.</t> copying it as a "bitrate=&lt;value&gt;" string.</li>
<li>The parameter "tcmax" goes in the SDP "a=fmtp" attribute by
<t>The parameter "bitrate" goes in the SDP "a=fmtp" attribute by copying it as a "tcmax=&lt;value&gt;" string.</li>
copying it as a "bitrate=&lt;value&gt;" string.</t> <li>The parameters "ptime" and "maxptime" go in the SDP "a=ptime" and
"a=maxptime" attributes, respectively.</li>
<t>The parameter "tcmax" goes in the SDP "a=fmtp" attribute by </ul>
copying it as a "tcmax=&lt;value&gt;" string.</t> <t>
When conveying information via SDP, the encoding name <bcp14>SHALL</bcp14> be
<t>The parameters "ptime" and "maxptime" go in the SDP "a=ptime" and
"a=maxptime" attributes, respectively.</t>
</list>
</t>
<t>
When conveying information via SDP, the encoding name SHALL be
"TSVCIS" (the same as the media subtype).</t> "TSVCIS" (the same as the media subtype).</t>
<t>
<t>
An example of the media representation in SDP for describing TSVCIS An example of the media representation in SDP for describing TSVCIS
might be:</t> might be:</t>
<sourcecode type="sdp"><![CDATA[
<figure><artwork><![CDATA[
m=audio 49120 RTP/AVP 96 m=audio 49120 RTP/AVP 96
a=rtpmap:96 TSVCIS/8000 a=rtpmap:96 TSVCIS/8000
]]></artwork> ]]></sourcecode>
</figure> <t>
<t> The optional media type parameter "bitrate", when present, <bcp14>MUST</bcp14
The optional media type parameter "bitrate", when present, MUST be > be
included in the "a=fmtp" attribute in the SDP, expressed as a media included in the "a=fmtp" attribute in the SDP, expressed as a media
type string in the form of a semicolon-separated list of type string in the form of a semicolon-separated list of
parameter=value pairs. The string "value" can be one or more of parameter=value pairs. The string "value" can be one or more of
2400, 1200, and 600, separated by commas (where each bitrate value 2400, 1200, and 600, separated by commas (where each bitrate value
indicates the corresponding MELPe coder). An example of the media indicates the corresponding MELPe coder). An example of the media
representation in SDP for describing TSVCIS when all three coder representation in SDP for describing TSVCIS when all three coder
bitrates are supported might be:</t> bitrates are supported might be:</t>
<sourcecode type="sdp"><![CDATA[
<figure><artwork><![CDATA[
m=audio 49120 RTP/AVP 96 m=audio 49120 RTP/AVP 96
a=rtpmap:96 TSVCIS/8000 a=rtpmap:96 TSVCIS/8000
a=fmtp:96 bitrate=2400,600,1200 a=fmtp:96 bitrate=2400,600,1200
]]></artwork> ]]></sourcecode>
</figure> <t>
<t> The optional media type parameter "tcmax", when present, <bcp14>MUST</bcp14>
The optional media type parameter "tcmax", when present, MUST be be
included in the "a=fmtp" attribute in the SDP, expressed as a media included in the "a=fmtp" attribute in the SDP, expressed as a media
type string in the form of a semicolon-separated list of type string in the form of a semicolon-separated list of
parameter=value pairs. The string "value" is an integer number in parameter=value pairs. The string "value" is an integer number in
the range of 1 to 255 representing the maximum number of TSVCIS the range of 1 to 255 representing the maximum number of TSVCIS
parameter octets supported. An example of the media representation parameter octets supported. An example of the media representation
in SDP for describing TSVCIS with a maximum of 101 octets supported in SDP for describing TSVCIS with a maximum of 101 octets supported
is as follows:</t> is as follows:</t>
<sourcecode type="sdp"><![CDATA[
<figure><artwork><![CDATA[
m=audio 49120 RTP/AVP 96 m=audio 49120 RTP/AVP 96
a=rtpmap:96 TSVCIS/8000 a=rtpmap:96 TSVCIS/8000
a=fmtp:96 tcmax=101 a=fmtp:96 tcmax=101
]]></artwork> ]]></sourcecode>
</figure> <t>
<t>
The parameter "ptime" cannot be used for the purpose of specifying The parameter "ptime" cannot be used for the purpose of specifying
the TSVCIS operating mode, due to the fact that for certain values it the TSVCIS operating mode due to the fact that, for certain values, it
will be impossible to distinguish which mode is about to be used will be impossible to distinguish which mode is about to be used
(e.g., when ptime=68, it would be impossible to distinguish if the (e.g., when ptime=68, it would be impossible to distinguish whether the
packet is carrying one frame of 67.5 ms or three frames of 22.5 ms).</t> packet is carrying one frame of 67.5 ms or three frames of 22.5 ms).</t>
<t>
<t>
Note that the payload format (encoding) names are commonly shown in Note that the payload format (encoding) names are commonly shown in
upper case. Media subtypes are commonly shown in lower case. These upper case. Media subtypes are commonly shown in lower case. These
names are case insensitive in both places. Similarly, parameter names are case insensitive in both places. Similarly, parameter
names are case insensitive in both the media subtype name and the names are case insensitive in both the media subtype name and the
default mapping to the SDP a=fmtp attribute.</t> default mapping to the SDP a=fmtp attribute.</t>
</section>
</section> <section anchor="sect-4.3" numbered="true" toc="default">
<name>Declarative SDP Considerations</name>
<section title="Declarative SDP Considerations" anchor="sect-4.3"><t> <t>
For declarative media, the "bitrate" parameter specifies the possible For declarative media, the "bitrate" parameter specifies the possible
bitrates used by the sender. Multiple TSVCIS rtpmap values (such as bitrates used by the sender. Multiple TSVCIS rtpmap values (such as
97, 98, and 99, as used below) MAY be used to convey TSVCIS-coded 97, 98, and 99, as used below) <bcp14>MAY</bcp14> be used to convey TSVCIS-co ded
voice at different bitrates. The receiver can then select an voice at different bitrates. The receiver can then select an
appropriate TSVCIS codec by using 97, 98, or 99.</t> appropriate TSVCIS codec by using 97, 98, or 99.</t>
<sourcecode type="sdp"><![CDATA[
<figure><artwork><![CDATA[
m=audio 49120 RTP/AVP 97 98 99 m=audio 49120 RTP/AVP 97 98 99
a=rtpmap:97 TSVCIS/8000 a=rtpmap:97 TSVCIS/8000
a=fmtp:97 bitrate=2400 a=fmtp:97 bitrate=2400
a=rtpmap:98 TSVCIS/8000 a=rtpmap:98 TSVCIS/8000
a=fmtp:98 bitrate=1200 a=fmtp:98 bitrate=1200
a=rtpmap:99 TSVCIS/8000 a=rtpmap:99 TSVCIS/8000
a=fmtp:99 bitrate=600 a=fmtp:99 bitrate=600
]]></artwork> ]]></sourcecode>
</figure> <t>
<t>
For declarative media, the "tcmax" parameter specifies the maximum For declarative media, the "tcmax" parameter specifies the maximum
number of TSVCIS packed parameter octets used by the sender or the number of octets of TSVCIS packed parameters used by the sender or the
sender's communications channel.</t> sender's communications channel.</t>
</section>
</section> <section anchor="sect-4.4" numbered="true" toc="default">
<name>Offer/Answer SDP Considerations</name>
<section title="Offer/Answer SDP Considerations" anchor="sect-4.4"><t> <t>
In the Offer/Answer model <xref target="RFC3264"/>, "bitrate" is a bidirectio In the Offer/Answer model <xref target="RFC3264" format="default"/>, "bitrate
nal " is a bidirectional
parameter. Both sides MUST use a common "bitrate" value or values. parameter. Both sides <bcp14>MUST</bcp14> use a common "bitrate" value or va
lues.
The offer contains the bitrates supported by the offerer, listed in The offer contains the bitrates supported by the offerer, listed in
its preferred order. The answerer MAY agree to any bitrate by its preferred order. The answerer <bcp14>MAY</bcp14> agree to any bitrate by
listing the bitrate first in the answerer response. Additionally, listing the bitrate first in the answerer response. Additionally,
the answerer MAY indicate any secondary bitrate or bitrates that it the answerer <bcp14>MAY</bcp14> indicate any secondary bitrate or bitrates th
supports. The initial bitrate used by both parties SHALL be the at it
supports. The initial bitrate used by both parties <bcp14>SHALL</bcp14> be t
he
first bitrate specified in the answerer response.</t> first bitrate specified in the answerer response.</t>
<t> <t>
For example, if offerer bitrates are "2400,600" and answer bitrates For example, if offerer bitrates are "2400,600" and answerer bitrates
are "600,2400", the initial bitrate is 600. If other bitrates are are "600,2400", the initial bitrate is 600. If other bitrates are
provided by the answerer, any common bitrate between the offer and provided by the answerer, any common bitrate between the offer and
answer MAY be used at any time in the future. Activation of these answer <bcp14>MAY</bcp14> be used at any time in the future. Activation of t hese
other common bitrates is beyond the scope of this document.</t> other common bitrates is beyond the scope of this document.</t>
<t>
<t>
The use of a lower bitrate is often important for a case such as when The use of a lower bitrate is often important for a case such as when
one endpoint utilizes a bandwidth-constrained link (e.g., 1200 bps one endpoint utilizes a bandwidth-constrained link (e.g., 1200 bps
radio link or slower), where only the lower coder bitrate will work.</t> radio link or slower), where only the lower coder bitrate will work.</t>
<t>
<t> In the Offer/Answer model <xref target="RFC3264" format="default"/>, "tcmax"
In the Offer/Answer model <xref target="RFC3264"/>, "tcmax" is a bidirectiona is a bidirectional
l parameter. Both sides <bcp14>SHOULD</bcp14> use a common "tcmax" value. The
parameter. Both sides SHOULD use a common "tcmax" value. The offer offer
contains the tcmax supported by the offerer. The answerer MAY agree contains the tcmax supported by the offerer. The answerer <bcp14>MAY</bcp14>
to any tcmax equal or less than this value by stating the desired agree
tcmax in the answerer response. The answerer alternatively MAY to any tcmax equal to or less than this value by stating the desired
tcmax in the answerer response. The answerer alternatively <bcp14>MAY</bcp14
>
identify its own tcmax and rely on TSVCIS ignoring any augmented data identify its own tcmax and rely on TSVCIS ignoring any augmented data
it cannot use.</t> it cannot use.</t>
</section>
</section> </section>
<section anchor="sect-5" numbered="true" toc="default">
</section> <name>Discontinuous Transmissions</name>
<t>
<section title="Discontinuous Transmissions" anchor="sect-5"><t>
A primary application of TSVCIS is for radio communications of voice A primary application of TSVCIS is for radio communications of voice
conversations, and discontinuous transmissions are normal. When conversations, and discontinuous transmissions are normal. When
TSVCIS is used in an IP network, TSVCIS RTP packet transmissions may TSVCIS is used in an IP network, TSVCIS RTP packet transmissions may
cease and resume frequently. RTP synchronization source (SSRC) cease and resume frequently. RTP synchronization source (SSRC)
sequence number gaps indicate lost packets to be filled by Packet sequence number gaps indicate lost packets to be filled by Packet
Loss Concealment (PLC), while abrupt loss of RTP packets indicates Loss Concealment (PLC), while abrupt loss of RTP packets indicates
intended discontinuous transmissions. Resumption of voice intended discontinuous transmissions. Resumption of voice
transmission SHOULD be indicated by the RTP marker bit (M) set to 1.</t> transmission <bcp14>SHOULD</bcp14> be indicated by the RTP marker bit (M) set
to 1.</t>
<t>If a TSVCIS coder so desires, it may send a MELPe comfort noise frame as <t>If a TSVCIS coder so desires, it may send a MELPe comfort noise frame a
per Appendix B of <xref target="SCIP210"/> prior to ceasing transmission. A s
per Appendix B of <xref target="SCIP210" format="default"/> prior to ceasing
transmission. A
receiver may optionally use comfort noise during its silence periods. No receiver may optionally use comfort noise during its silence periods. No
SDP negotiations are required. SDP negotiations are required.
</t> </t>
</section>
</section> <section anchor="sect-6" numbered="true" toc="default">
<name>Packet Loss Concealment</name>
<section title="Packet Loss Concealment" anchor="sect-6"><t> <t>
TSVCIS packet loss concealment (PLC) uses the special properties and TSVCIS packet loss concealment (PLC) uses the special properties and
coding for the pitch/voicing parameter of the MELPe 2400 bps coder. coding for the pitch/voicing parameter of the MELPe 2400 bps coder.
The PLC erasure indication utilizes any of the errored encodings of a The PLC erasure indication utilizes any of the errored encodings of a
non-voiced frame as identified in Table 1 of <xref target="MELPE"/>. For the sake of non-voiced frame as identified in Table 1 of <xref target="MELPE" format="def ault"/>. For the sake of
simplicity, it is preferred that a code value of 3 for the simplicity, it is preferred that a code value of 3 for the
pitch/voicing parameter be used. Hence, set bits P0 and P1 to one pitch/voicing parameter be used. Hence, set bits P0 and P1 to one
and bits P2, P3, P4, P5, and P6 to zero.</t> and bits P2, P3, P4, P5, and P6 to zero.</t>
<t>
<t>
When using PLC in 1200 bps or 600 bps mode, the MELPe 2400 bps When using PLC in 1200 bps or 600 bps mode, the MELPe 2400 bps
decoder is called three or four times, respectively, to cover the decoder is called three or four times, respectively, to cover the
loss of a low bitrate MELPe frame.</t> loss of a low bitrate MELPe frame.</t>
</section>
</section> <section anchor="sect-7" numbered="true" toc="default">
<name>IANA Considerations</name>
<section title="IANA Considerations" anchor="sect-7"><t> <t>
This memo requests that IANA registers TSVCIS as specified in <xref target="s IANA has registered TSVCIS as specified in <xref target="sect-4.1"
ect-4.1"/>. The media type is also requested to be added to the IANA format="default"/>. The media type has been added to the IANA
registry for "RTP Payload Format MIME types" registry for "RTP Payload Format Media Types"
(<eref target="http://www.iana.org/assignments/rtp-parameters"/>).</t> (<eref target="https://www.iana.org/assignments/rtp-parameters"/>).</t>
</section>
</section> <section anchor="sect-8" numbered="true" toc="default">
<name>Security Considerations</name>
<section title="Security Considerations" anchor="sect-8"><t> <t>
RTP packets using the payload format defined in this specification RTP packets using the payload format defined in this specification
are subject to the security considerations discussed in the RTP are subject to the security considerations discussed in the RTP
specification <xref target="RFC3550"/> and in any applicable RTP profile such specification <xref target="RFC3550" format="default"/> and in any applicable
as RTP profile such as
RTP/AVP <xref target="RFC3551"/>, RTP/AVPF <xref target="RFC4585"/>, RTP/SAVP RTP/AVP <xref target="RFC3551" format="default"/>, RTP/AVPF <xref target="RFC
<xref target="RFC3711"/>, or 4585" format="default"/>, RTP/SAVP <xref target="RFC3711" format="default"/>, or
RTP/SAVPF <xref target="RFC5124"/>. However, as discussed in <xref target="R RTP/SAVPF <xref target="RFC5124" format="default"/>. However, as discussed i
FC7202"/>, it is not n <xref target="RFC7202" format="default"/>, it is not
an RTP payload format's responsibility to discuss or mandate what an RTP payload format's responsibility to discuss or mandate what
solutions are used to meet such basic security goals as solutions are used to meet such basic security goals as
confidentiality, integrity, and source authenticity for RTP in confidentiality, integrity, and source authenticity for RTP in
general. This responsibility lies with anyone using RTP in an general. This responsibility lies with anyone using RTP in an
application. They can find guidance on available security mechanisms application. They can find guidance on available security mechanisms
and important considerations in <xref target="RFC7201"/>. Applications SHOUL D use and important considerations in <xref target="RFC7201" format="default"/>. A pplications <bcp14>SHOULD</bcp14> use
one or more appropriate strong security mechanisms. The rest of this one or more appropriate strong security mechanisms. The rest of this
section discusses the security-impacting properties of the payload section discusses the security-impacting properties of the payload
format itself.</t> format itself.</t>
<t>
<t>
This RTP payload format and the TSVCIS decoder, to the best of our This RTP payload format and the TSVCIS decoder, to the best of our
knowledge, do not exhibit any significant non-uniformity in the knowledge, do not exhibit any significant non-uniformity in the
receiver-side computational complexity for packet processing and thus receiver-side computational complexity for packet processing and thus
are unlikely to pose a denial-of-service threat due to the receipt of are unlikely to pose a denial-of-service threat due to the receipt of
pathological data. Additionally, the RTP payload format does not pathological data. Additionally, the RTP payload format does not
contain any active content.</t> contain any active content.</t>
<t>
<t> Please see the security considerations discussed in <xref target="RFC6562" fo
Please see the security considerations discussed in <xref target="RFC6562"/> rmat="default"/>
regarding Voice Activity Detect (VAD) and its effect on bitrates.</t> regarding Voice Activity Detect (VAD) and its effect on bitrates.</t>
</section>
</section> </middle>
<back>
</middle> <references>
<name>References</name>
<back> <references>
<references title="Normative References"> <name>Normative References</name>
&RFC2119; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC8174; FC.2119.xml"/>
&RFC2736; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC8088; FC.8174.xml"/>
&RFC3264; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC3550; FC.2736.xml"/>
&RFC3551; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC8130; FC.8088.xml"/>
&RFC3711; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC4566; FC.3264.xml"/>
&RFC4855; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC5124; FC.3550.xml"/>
&RFC6562; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC6838; FC.3551.xml"/>
&RFC8083; <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
&RFC8085; FC.8130.xml"/>
<reference anchor="NRLVDR"><front> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
<title>Universal Vocoder Using Variable Data Rate Vocoding</title> FC.3711.xml"/>
<author initials="D." surname="Heide" fullname="D. Heide"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
</author> FC.4566.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
<author initials="A." surname="Cohen" fullname="A. Cohen"> FC.4855.xml"/>
</author> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.5124.xml"/>
<author initials="Y." surname="Lee" fullname="Y. Lee"> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
</author> FC.6562.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
<author initials="T." surname="Moran" fullname="T. Moran"> FC.6838.xml"/>
</author> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.8083.xml"/>
<date month="June" year="2013"/> <xi:include
</front> href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8085.x
ml"/>
<seriesInfo name="Naval Research Lab" value="NRL/FR/5555-13-10, 239"/> <reference anchor="NRLVDR">
</reference> <front>
<reference anchor="MELP"><front> <title>Universal Vocoder Using Variable Data Rate Vocoding</title>
<title>Analog-to-Digital Conversion of Voice by 2,400 Bit/Second Mixed Ex <seriesInfo name="DOI" value="10.21236/ada588068"/>
citation Linear Prediction (MELP)</title> <seriesInfo name="Naval Research Lab" value="NRL/FR/5555--13-10, 239
<author> "/>
<organization>Department of Defense Telecommunications Standard</organiza <author initials="D." surname="Heide" fullname="David Heide">
tion>
</author>
<date month="December" year="1999"/>
</front>
<seriesInfo name="" value="MIL-STD-3005"/>
</reference>
<reference anchor="MELPE"><front>
<title>The 600 Bit/S, 1200 Bit/S and 2400 Bit/S NATO Interoperable Narrow
Band Voice Coder</title>
<author>
<organization>North Atlantic Treaty Organization (NATO)</organization>
</author> </author>
<author initials="A." surname="Cohen" fullname="Aaron Cohen">
<date month="January" year="2006"/>
</front>
<seriesInfo name="STANAG" value="No. 4591"/>
</reference>
<reference anchor="SCIP210"><front>
<title>SCIP Signaling Plan</title>
<author>
<organization>National Security Agency</organization>
</author> </author>
<author initials="Y." surname="Lee" fullname="Yvette Lee">
<date month="December" year="2007"/>
</front>
<seriesInfo name="" value="SCIP-210"/>
</reference>
</references>
<references title="Informative References">
<reference anchor="TSVCIS"><front>
<title>Tactical Secure Voice Cryptographic Interoperability Specification
(TSVCIS) Version 3.1</title>
<author>
<organization>National Security Agency</organization>
</author> </author>
<author initials="T." surname="Moran" fullname="Thomas Moran">
<date month="March" year="2019"/>
</front>
<seriesInfo name="NSA" value="09-01A"/>
</reference>
&RFC4585;
&RFC7201;
&RFC7202;
<reference anchor="RMCAT" target="https://datatracker.ietf.org/wg/rmcat/a
bout/"><front>
<title>RTP Media Congestion Avoidance Techniques (rmcat) Working Group</t
itle>
<author>
<organization>IETF</organization>
</author> </author>
<date month="June" year="2013"/>
</front>
</reference>
<reference anchor="MELP">
<front>
<title>Analog-to-Digital Conversion of Voice by 2,400 Bit/Second Mix
ed Excitation Linear Prediction (MELP)</title>
<seriesInfo name="Department of Defense Telecommunications Standard"
value="MIL-STD-3005"/>
<author>
<organization>Department of Defense</organization>
</author>
<date month="December" year="1999"/>
</front>
</reference>
<reference anchor="MELPE">
<front>
<title>The 600 Bit/S, 1200 Bit/S and 2400 Bit/S NATO Interoperable N
arrow Band Voice Coder</title>
<seriesInfo name="STANAG" value="No. 4591"/>
<author>
<organization>North Atlantic Treaty Organization (NATO)</organizat
ion>
</author>
<date month="October" year="2008"/>
</front>
</reference>
<reference anchor="SCIP210">
<front>
<title>SCIP Signaling Plan</title>
<author>
<organization>National Security Agency</organization>
</author>
<date month="January" year="2013"/>
</front>
<refcontent>SCIP-210</refcontent>
</reference>
</references>
<date/> <references>
</front> <name>Informative References</name>
<reference anchor="TSVCIS">
</reference> <front>
</references> <title>Tactical Secure Voice Cryptographic Interoperability Specific
</back> ation (TSVCIS) Version 3.1</title>
<seriesInfo name="NSA" value="09-01A"/>
</rfc> <author>
<organization>National Security Agency</organization>
</author>
<date month="March" year="2019"/>
</front>
</reference>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.4585.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7201.xml"/>
<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.R
FC.7202.xml"/>
<reference anchor="RMCAT" target="https://datatracker.ietf.org/wg/rmcat/
about/">
<front>
<title>RTP Media Congestion Avoidance Techniques (rmcat) Working Gro
up</title>
<author>
<organization>IETF</organization>
</author>
</front>
</reference>
</references>
</references>
</back>
</rfc>
 End of changes. 117 change blocks. 
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