forked from xiph/speex
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathdraft-ietf-avt-rtp-speex-00.txt
784 lines (461 loc) · 25.9 KB
/
draft-ietf-avt-rtp-speex-00.txt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
AVT Working Group G. Herlein
Internet-Draft S. Morlat
Expires: April 15, 2006 J. Jean-Marc
R. Hardiman
P. Kerr
October 12, 2005
draft-ietf-avt-rtp-speex-00
RTP Payload Format for the Speex Codec
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 15, 2006.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
Speex is an open-source voice codec suitable for use in Voice over IP
(VoIP) type applications. This document describes the payload format
for Speex generated bit streams within an RTP packet. Also included
here are the necessary details for the use of Speex with the Session
Description Protocol (SDP).
Herlein, et al. Expires April 15, 2006 [Page 1]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
Editors Note
All references to RFC XXXX are to be replaced by references to the
RFC number of this memo, when published.
Table of Contents
1. Conventions used in this document . . . . . . . . . . . . . 3
2. Overview of the Speex Codec . . . . . . . . . . . . . . . . 3
3. RTP payload format for Speex . . . . . . . . . . . . . . . . 3
4. RTP Header . . . . . . . . . . . . . . . . . . . . . . . . . 3
5. Speex payload . . . . . . . . . . . . . . . . . . . . . . . 5
6. Example Speex packet . . . . . . . . . . . . . . . . . . . . 6
7. Multiple Speex frames in a RTP packet . . . . . . . . . . . 6
8. MIME registration of Speex . . . . . . . . . . . . . . . . . 7
9. SDP usage of Speex . . . . . . . . . . . . . . . . . . . . . 8
10. ITU H.323 Use of Speex . . . . . . . . . . . . . . . . . . . 10
11. Security Considerations . . . . . . . . . . . . . . . . . . 10
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 11
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
13.1 Normative References . . . . . . . . . . . . . . . . . . 11
13.2 Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 12
Intellectual Property and Copyright Statements . . . . . . . 14
Herlein, et al. Expires April 15, 2006 [Page 2]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
1. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [1].
2. Overview of the Speex Codec
Speex is based on the CELP [8] encoding technique with support for
either narrowband (nominal 8kHz), wideband (nominal 16kHz) or ultra-
wideband (nominal 32kHz), and (non-optimal) rates up to 48 kHz
sampling also available. The main characteristics can be summarized
as follows:
o Free software/open-source
o Integration of wideband and narrowband in the same bit-stream
o Wide range of bit-rates available
o Dynamic bit-rate switching and variable bit-rate (VBR)
o Voice Activity Detection (VAD, integrated with VBR)
o Variable complexity
3. RTP payload format for Speex
For RTP based transportation of Speex encoded audio the standard RTP
header [2] is followed by one or more payload data blocks. An
optional padding terminator may also be used.
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 |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| one or more frames of Speex .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| one or more frames of Speex .... | padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4. RTP Header
Herlein, et al. Expires April 15, 2006 [Page 3]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|X| CC |M| PT | sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| synchronization source (SSRC) identifier |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| contributing source (CSRC) identifiers |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The RTP header begins with an octet of fields (V, P, X, and CC) to
support specialized RTP uses (see [2] and [5] for details). For
Speex the following values are used.
Version (V): 2 bits
This field identifies the version of RTP. The version used by this
specification is two [2].
Padding (P): 1 bit
If the padding bit is set, the packet contains one or more additional
padding octets at the end which are not part of the payload.
Extension (X): 1 bit
If the extension, X, bit is set, the fixed header MUST be followed by
exactly one header extension, with a format defined in Section 5.3.1.
of [2].
CSRC count (CC): 4 bits
The CSRC count contains the number of CSRC identifiers.
Marker (M): 1 bit
The M bit indicates if the packet contains comfort noise. This field
is used in conjunction with the cng SDP attribute and conforms to
Section 4.1. of [5].
Payload Type (PT): 7 bits
An RTP profile for a class of applications is expected to assign a
payload type for this format, or a dynamically allocated payload type
SHOULD be chosen which designates the payload as Speex.
Herlein, et al. Expires April 15, 2006 [Page 4]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
Sequence number: 16 bits
The sequence number increments by one for each RTP data packet sent,
and may be used by the receiver to detect packet loss and to restore
packet sequence. This field is detailed further in [2].
Timestamp: 32 bits
A timestamp representing the sampling time of the first sample of the
first Speex packet in the RTP packet. The clock frequency MUST be
set to the sample rate of the encoded audio data. Speex uses 20 msec
frames and a variable sampling rate clock. The RTP timestamp MUST be
in units of 1/X of a second where X is the sample rate used. Speex
uses a nominal 8kHz sampling rate for narrowband use, a nominal 16kHz
sampling rate for wideband use, and a nominal 32kHz sampling rate for
ultra-wideband use.
SSRC/CSRC identifiers:
These two fields, 32 bits each with one SSRC field and a maximum of
16 CSRC fields, are as defined in [2].
5. Speex payload
For the purposes of packetizing the bit stream in RTP, it is only
necessary to consider the sequence of bits as output by the Speex
encoder [7], and present the same sequence to the decoder. The
payload format described here maintains this sequence.
A typical Speex frame, encoded at the maximum bitrate, is approx. 110
octets and the total number of Speex frames SHOULD be kept less than
the path MTU to prevent fragmentation. Speex frames MUST NOT be
fragmented across multiple RTP packets,
An RTP packet MAY contain Speex frames of the same bit rate or of
varying bit rates, since the bit-rate for a frame is conveyed in band
with the signal.
The encoding and decoding algorithm can change the bit rate at any 20
msec frame boundary, with the bit rate change notification provided
in-band with the bit stream. Each frame contains both "mode"
(narrowband, wideband or ultra-wideband) and "sub-mode" (bit-rate)
information in the bit stream. No out-of-band notification is
required for the decoder to process changes in the bit rate sent by
the encoder.
It is RECOMMENDED that values of 8000, 16000 and 32000 be used for
normal internet telephony applications, though the sample rate is
Herlein, et al. Expires April 15, 2006 [Page 5]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
supported at rates as low as 6000 Hz and as high as 48 kHz.
The RTP payload MUST be padded to provide an integer number of octets
as the payload length. These padding bits are LSB aligned in network
octet order and consist of a 0 followed by all ones (until the end of
the octet). This padding is only required for the last frame in the
packet, and only to ensure the packet contents ends on an octet
boundary.
6. Example Speex packet
In the example below we have a single Speex frame with 5 bits of
padding to ensure the packet size falls on an octet boundary.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|X| CC |M| PT | sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| synchronization source (SSRC) identifier |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
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
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| contributing source (CSRC) identifiers |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ..speex data.. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ..speex data.. |0 1 1 1 1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
7. Multiple Speex frames in a RTP packet
Below is an example of two Speex frames contained within one RTP
packet. The Speex frame length in this example fall on an octet
boundary so there is no padding.
Speex codecs [7] are able to detect the bitrate from the payload and
are responsible for detecting the 20 msec boundaries between each
frame.
Herlein, et al. Expires April 15, 2006 [Page 6]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|X| CC |M| PT | sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| synchronization source (SSRC) identifier |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| contributing source (CSRC) identifiers |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ..speex data.. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ..speex data.. | ..speex data.. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ..speex data.. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
8. MIME registration of Speex
Full definition of the MIME [3] type for Speex will be part of the
Ogg Vorbis MIME type definition application [6].
MIME media type name: audio
MIME subtype: speex
Optional parameters:
Required parameters: to be included in the Ogg MIME specification.
Encoding considerations:
This type is only defined for transfer via HTTP as specified in RFC
XXXX.
Security Considerations:
See Section 6 of RFC 3047.
Interoperability considerations: none
Published specification:
Applications which use this media type:
Herlein, et al. Expires April 15, 2006 [Page 7]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
Additional information: none
Person & email address to contact for further information:
Greg Herlein <[email protected]>
Jean-Marc Valin <[email protected]>
Intended usage: COMMON
Author/Change controller:
Author: Greg Herlein <[email protected]>
Change controller: Greg Herlein <[email protected]>
Change controller: IETF AVT Working Group
This transport type signifies that the content is to be interpreted
according to this document if the contents are transmitted over RTP.
Should this transport type appear over a lossless streaming protocol
such as TCP, the content encapsulation should be interpreted as an
Ogg Stream in accordance with [6], with the exception that the
content of the Ogg Stream may be assumed to be Speex audio and Speex
audio only.
9. SDP usage of Speex
When conveying information by SDP [4], the encoding name MUST be set
to "speex". An example of the media representation in SDP for
offering a single channel of Speex at 8000 samples per second might
be:
m=audio 8088 RTP/AVP 97
a=rtpmap:97 speex/8000
Note that the RTP payload type code of 97 is defined in this media
definition to be 'mapped' to the speex codec at an 8kHz sampling
frequency using the 'a=rtpmap' line. Any number from 96 to 127 could
have been chosen (the allowed range for dynamic types).
The value of the sampling frequency is typically 8000 for narrow band
operation, 16000 for wide band operation, and 32000 for ultra-wide
band operation.
If for some reason the offerer has bandwidth limitations, the client
may use the "b=" header, as explained in SDP [4]. The following
example illustrates the case where the offerer cannot receive more
than 10 kbit/s.
Herlein, et al. Expires April 15, 2006 [Page 8]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
m=audio 8088 RTP/AVP 97
b=AS:10
a=rtmap:97 speex/8000
In this case, if the remote part agrees, it should configure its
Speex encoder so that it does not use modes that produce more than 10
kbit/s. Note that the "b=" constraint also applies on all payload
types that may be proposed in the media line ("m=").
An other way to make recommendations to the remote Speex encoder is
to use its specific parameters via the a=fmtp: directive. The
following parameters are defined for use in this way:
ptime: duration of each packet in milliseconds.
sr: actual sample rate in Hz.
ebw: encoding bandwidth - either 'narrow' or 'wide' or 'ultra'
(corresponds to nominal 8000, 16000, and 32000 Hz sampling rates).
vbr: variable bit rate - either 'on' 'off' or 'vad' (defaults
to off). If on, variable bit rate is enabled. If off, disabled.
If set to 'vad' then constant bit rate is used but silence will be
encoded with special short frames to indicate a lack of voice for
that period.
cng: comfort noise generation - either 'on' or 'off'. If off
then silence frames will be silent; if 'on' then those frames will
be filled with comfort noise.
mode: Speex encoding mode. Can be {1,2,3,4,5,6,any} defaults to
3 in narrowband, 6 in wide and ultra-wide.
Examples:
m=audio 8008 RTP/AVP 97
a=rtpmap:97 speex/8000
a=fmtp:97 mode=4
This examples illustrate an offerer that wishes to receive a Speex
stream at 8000Hz, but only using speex mode 4.
Several Speex specific parameters can be given in a single a=fmtp
line provided that they are separated by a semi-colon:
Herlein, et al. Expires April 15, 2006 [Page 9]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
a=fmtp:97 mode=any;mode=1
The offerer may indicate that it wishes to send variable bit rate
frames with comfort noise:
m=audio 8088 RTP/AVP 97
a=rtmap:97 speex/8000
a=fmtp:97 vbr=on;cng=on
The "ptime" attribute is used to denote the packetization interval
(ie, how many milliseconds of audio is encoded in a single RTP
packet). Since Speex uses 20 msec frames, ptime values of multiples
of 20 denote multiple Speex frames per packet. Values of ptime which
are not multiples of 20 MUST be ignored and clients MUST use the
default value of 20 instead.
In the example below the ptime value is set to 40, indicating that
there are 2 frames in each packet.
m=audio 8008 RTP/AVP 97
a=rtpmap:97 speex/8000
a=ptime:40
Note that the ptime parameter applies to all payloads listed in the
media line and is not used as part of an a=fmtp directive.
Values of ptime not multiple of 20 msec are meaningless, so the
receiver of such ptime values MUST ignore them. If during the life
of an RTP session the ptime value changes, when there are multiple
Speex frames for example, the SDP value must also reflect the new
value.
Care must be taken when setting the value of ptime so that the RTP
packet size does not exceed the path MTU.
10. ITU H.323 Use of Speex
It is outside the scope of this document to cover the use of Speex
and H.323, more details may be found on the Speex website [9].
11. Security Considerations
RTP packets using the payload format defined in this specification
are subject to the security considerations discussed in the RTP
specification [2], and any appropriate RTP profile. This implies
that confidentiality of the media streams is achieved by encryption.
Because the data compression used with this payload format is applied
end-to-end, encryption may be performed after compression so there is
Herlein, et al. Expires April 15, 2006 [Page 10]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
no conflict between the two operations.
A potential denial-of-service threat exists for data encodings using
compression techniques that have non-uniform receiver-end
computational load. The attacker can inject pathological datagrams
into the stream which are complex to decode and cause the receiver to
be overloaded. However, this encoding does not exhibit any
significant non-uniformity.
As with any IP-based protocol, in some circumstances a receiver may
be overloaded simply by the receipt of too many packets, either
desired or undesired. Network-layer authentication may be used to
discard packets from undesired sources, but the processing cost of
the authentication itself may be too high.
12. Acknowledgments
The authors would like to thank Equivalence Pty Ltd of Australia for
their assistance in attempting to standardize the use of Speex in
H.323 applications, and for implementing Speex in their open source
OpenH323 stack. The authors would also like to thank Brian C. Wiles
<[email protected]> of StreamComm for his assistance in developing
the proposed standard for Speex use in H.323 applications.
The authors would also like to thank the following members of the
Speex and AVT communities for their input: Ross Finlayson, Federico
Montesino Pouzols, Henning Schulzrinne, Magnus Westerlund.
13. References
13.1 Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119.
[2] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,
"RTP: A Transport Protocol for real-time applications",
RFC 3550.
[3] "Multipurpose Internet Mail Extensions (MIME) Part One: Format
of Internet Message Bodies", RFC 2045.
[4] Jacobson, V. and M. Handley, "SDP: Session Description
Protocol", RFC 2327.
[5] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video
Conferences with Minimal Control.", RFC 3551.
Herlein, et al. Expires April 15, 2006 [Page 11]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
[6] Walleij, L., "The application/ogg Media Type", RFC 3534.
13.2 Informative References
[7] "Speexenc/speexdec, reference command-line encoder/decoder",
Speex website http://www.speex.org/.
[8] "CELP, U.S. Federal Standard 1016.", National Technical
Information Service (NTIS) website http://www.ntis.gov/.
[9] "ITU H.323/H.245 Use of Speex", Speex
website http://www.speex.org/itu/.
Authors' Addresses
Greg Herlein
2034 Filbert Street
San Francisco, California 94123
United States
Email: [email protected]
Simon Morlat
35, av de Vizille App 42
Grenoble 38000
France
Email: [email protected]
Jean-Marc Valin
Department of Electrical and Computer Engineering
University of Sherbrooke
2500 blvd Universite
Sherbrooke, Quebec J1K 2R1
Canada
Email: [email protected]
Herlein, et al. Expires April 15, 2006 [Page 12]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
Roger Hardiman
49 Nettleton Road
Cheltenham, Gloucestershire GL51 6NR
England
Email: [email protected]
Phil Kerr
England
Email: [email protected]
Herlein, et al. Expires April 15, 2006 [Page 13]
Internet-Draft draft-ietf-avt-rtp-speex-00 October 2005
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2005). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment
Funding for the RFC Editor function is currently provided by the
Internet Society.
Herlein, et al. Expires April 15, 2006 [Page 14]