draft-ietf-payload-tsvcis-00.txt   draft-ietf-payload-tsvcis-01.txt 
Payload Working Group Victor Demjanenko Payload Working Group Victor Demjanenko
Internet-Draft John Punaro Internet-Draft John Punaro
Intended Status: Standards Track David Satterlee Intended Status: Standards Track David Satterlee
VOCAL Technologies, Ltd. VOCAL Technologies, Ltd.
Expires: October 18, 2018 April 16, 2018 Expires: April 19, 2019 October 16, 2018
RTP Payload Format for TSVCIS Codec RTP Payload Format for TSVCIS Codec
draft-ietf-payload-tsvcis-00 draft-ietf-payload-tsvcis-01
Status of This Memo Status of This Memo
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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
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9. RFC Editor Considerations . . . . . . . . . . . . . . . . . . 17 9. RFC Editor Considerations . . . . . . . . . . . . . . . . . . 17
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. Normative References . . . . . . . . . . . . . . . . . . 17 10.1. Normative References . . . . . . . . . . . . . . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . 19 10.2. Informative References . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction
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 may be formatted for use as an RTP produced by the TSVCIS codec [TSVCIS] [NRLVDR] may be formatted for
payload. The TSVCIS speech coder (or TSVCIS speech aware use as an RTP payload. The TSVCIS speech coder (or TSVCIS speech
communications equipment on any intervening transport link) may aware communications 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. coder for the most constrained bandwidth links.
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 a 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. tolerance.
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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, or 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. by the sender.
3.1. MELPe Bitstream Definitions 3.1. MELPe Bitstream Definitions
The TCVCIS speech coder includes all three MELPe coder rates used as The TCVCIS speech coder includes all three MELPe coder rates used as
base speech parameters or as speech coders for bandwidth restricted base speech parameters or as speech coders for bandwidth restricted
links. RTP packetization of MELPe follows RFC 8130 and is repeated links. RTP packetization of MELPe follows RFC 8130 and is repeated
here for all three MELPe rates [RFC8130] which with promoted here for all three MELPe rates [RFC8130] which with its
suggestions or recommendations now regarded as requirements. The recommendations now regarded as requirements. The bits previously
bits previously labeled as RSVA, RSVB, and RSVC in RFC 8130 SHOULD be labeled as RSVA, RSVB, and RSVC in RFC 8130 SHOULD be filled with
filled with rate coding, CODA, CODB, and CODC, as shown in Table 1 rate coding, CODA, CODB, and CODC, as shown in Table 1 (compatible
(compatible with Table 7 in Section 3.3 of [RFC8130]). with Table 7 in Section 3.3 of [RFC8130]).
+-------------------+------+------+------+------+ +-------------------+------+------+------+------+
| Coder Bitrate | CODA | CODB | CODC |Length| | Coder Bitrate | CODA | CODB | CODC |Length|
+-------------------+------+------+------+------+ +-------------------+------+------+------+------+
| 2400 bps | 0 | 0 | N/A | 7 | | 2400 bps | 0 | 0 | N/A | 7 |
+-------------------+------+------+------+------+ +-------------------+------+------+------+------+
| 1200 bps | 1 | 0 | 0 | 11 | | 1200 bps | 1 | 0 | 0 | 11 |
+-------------------+------+------+------+------+ +-------------------+------+------+------+------+
| 600 bps | 0 | 1 | N/A | 7 | | 600 bps | 0 | 1 | N/A | 7 |
+-------------------+------+------+------+------+ +-------------------+------+------+------+------+
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| TSVCIS data | 1 | 1 | N/A | var. | | TSVCIS data | 1 | 1 | N/A | var. |
+-------------------+------+------+------+------+ +-------------------+------+------+------+------+
Table 1: TSVCIS/MELPe Frame Bitrate Indicators and Frame Length Table 1: TSVCIS/MELPe Frame Bitrate Indicators and Frame Length
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 nosie 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 Section 3.2. in a trailing byte as discussed in Section 3.2.
It should be noted that CODB for both the 2400 and 600 bps modes MAY It should be noted that CODB for both the 2400 and 600 bps modes MAY
deviate from the values in Table 1 when bit 55 is used as an end-to- deviate from the values in Table 1 when bit 55 is used as an end-to-
end framing bit. Frame decoding would remain distinct as CODA being end framing bit. Frame decoding would remain distinct as CODA being
zero on its own would indicate a 7-byte frame for either rate and the zero on its own would indicate a 7-byte frame for either rate and the
use of 600 bps speech coding could be deduced from the RTP timestamp use of 600 bps speech coding could be deduced from the RTP timestamp
(and anticipated by the SDP negotiations). (and anticipated by the SDP negotiations).
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| 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 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
Figure 5: Packed MELPe Comfort Noise Payload Octets Figure 5: Packed MELPe Comfort Noise Payload Octets
3.2. TSVCIS Bitstream Definition 3.2. TSVCIS Bitstream Definition
The TSVCIS augmented speech data as packed parameters MUST be placed The TSVCIS augmented speech data as packed parameters MUST be placed
immediately after a corresponding MELPe 2400 bps payload. The packed immediately after a corresponding MELPe 2400 bps payload in the same
parameters are counted in octets (TC). In the preferred placement, RTP packet. The packed parameters are counted in octets (TC). In
shown in Figure 6, a single trailing octet SHALL be appended to the preferred placement, shown in Figure 6, a single trailing octet
include a two-bit rate code, CODA and CODB, (both bits set to one) SHALL be appended to include a two-bit rate code, CODA and CODB,
and a six-bit modified count (MTC). The special modified count value (both bits set to one) and a six-bit modified count (MTC). The
of all ones (representing a MTC value of 63) SHALL NOT be used for special modified count value of all ones (representing a MTC value of
this format as it is used as the indicator for the alternate packing 63) SHALL NOT be used for this format as it is used as the indicator
format shown next. In a standard implementation, the TSVCIS speech for the alternate packing format shown next. In a standard
coder uses a minimum of 15 octets for parameters in octet packed implementation, the TSVCIS speech coder uses a minimum of 15 octets
form. The modified count (MTC) MUST be reduced by 15 from the full for parameters in octet packed form. The modified count (MTC) MUST
octet count (TC). Computed MTC = TC-15. This accommodates a maximum be reduced by 15 from the full octet count (TC). Computed MTC = TC-
of 77 parameter octets (maximum value of MTC is 62, 77 is the sum of 15. This accommodates a maximum of 77 parameter octets (maximum
62+15). value of MTC is 62, 77 is the sum of 62+15).
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 |
+------+------+------+------+------+------+------+------+ +------+------+------+------+------+------+------+------+
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See Section 6 of RFC 4566 [RFC4566]. See Section 6 of RFC 4566 [RFC4566].
bitrate: specifies the MELPe coder bitrates supported. Possible bitrate: specifies the MELPe coder bitrates supported. Possible
values are a comma-separated list of rates from the following values are a comma-separated list of rates from the following
set: 2400, 1200, 600. The modes are listed in order of set: 2400, 1200, 600. The modes are listed in order of
preference; first is preferred. If "bitrate" is not present, preference; first is preferred. If "bitrate" is not present,
the fixed coder bitrate of 2400 MUST be used. the fixed coder bitrate of 2400 MUST be used.
tcmax: specifies the TSVCIS maximum value for TC supported or tcmax: specifies the TSVCIS maximum value for TC supported or
desired ranging from 1 to 255. If "tcmax" is not present, a desired ranging from 1 to 255. If "tcmax" is not present, a
default value of TBD is used. default value of 35 is used.
[EDITOR NOTE - the value for TBD is to be discussed and stated. [EDITOR NOTE - the value of 35 is suggested based on a
A value of 35 is suggested.] preferred 8kbps TSVCIS coder bitrate.]
Encoding considerations: This media subtype is framed and binary; see Encoding considerations: This media subtype is framed and binary; see
Section 4.8 of RFC 6838 [RFC6838]. Section 4.8 of RFC 6838 [RFC6838].
Security considerations: Please see Section 8 of RFCxxxx (this RFC). Security considerations: Please see Section 8 of RFC XXXX.
[EDITOR NOTE - please replace XXXX with the RFC number of this
document.]
Interoperability considerations: N/A Interoperability considerations: N/A
Published specification: N/A Published specification: N/A
Applications that use this media type: N/A Applications that use this media type: N/A
Additional information: N/A Additional information: N/A
Deprecated alias names for this type: N/A Deprecated alias names for this type: N/A
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