shithub: opus

--- a/doc/ietf/draft-valin-celt-rtp-profile.xml

+++ b/doc/ietf/draft-valin-celt-rtp-profile.xml

@@ -1,6 +1,6 @@

 <?xml version='1.0'?>

 <!DOCTYPE rfc SYSTEM 'rfc2629.dtd'>

-<?rfc toc="yes" ?>

+<?rfc symrefs="yes" toc="yes" ?>

 <rfc ipr="full3978" docName="RTP Payload Format for the CELT Codec">

@@ -435,7 +435,45 @@

<t>

 When conveying information by SDP <xref target="rfc2327"></xref>, the encoding name MUST be

-set to "CELT".  An example of the media representation in SDP for

+set to "CELT". The sampling frequency is typically between 32000 and 48000 Hz.

+Implementations SHOULD support both 44100 Hz and 48000 Hz. The maximum bandwidth permitted for

+the CELT audio is encoded using the  "b=AS:" header, as explained in SDP <xref target="rfc2327"></xref>.

+</t>

+<t>

+Several CELT-specific parameters can be given via the "a=fmtp:" directive.  The

+following parameters are defined for use in this way:

+</t>

+<t>

+<vspace blankLines="1" />

+<list style="empty">

+<t>frame-size: duration of each frame in samples. The default is 256.<vspace blankLines="1" /></t>

+<t>nb-frames: number of frames per packet (per stream). The default is 1.<vspace blankLines="1" /></t>

+<t>mapping: Optional string describing the multi-channel mapping. <vspace blankLines="1" /></t>

+</list>

+</t>

+<t>Several CELT specific parameters can be given in a single

+a=fmtp line provided that they are separated by a semi-colon.</t>

+<t>

+The selected frame-size value MUST be even. It SHOULD be divisible by 8

+and have a prime factorization which consists only 2, 3, or 5 factors.

+For example, powers-of-two and values such as 160, 320, 240, and 480 are

+recommended. Implementations SHOULD support receiving and sending the default

+value of 256, and if the size 256 is supported it MUST be offered.

+</t>

+<t>

+Care must be taken when setting the value of max-size and nb-frames so that the

+RTP packet size does not exceed the path MTU.

+</t>

+<t>An example of the media representation in SDP for

 offering a single channel of CELT at 48000 samples per second might

be:

 </t>

@@ -456,18 +494,10 @@

 </t>

<t>

-The value of the sampling frequency is typically between 32000 and 48000 Hz.

-Implementations should support both 44100 Hz and 48000 Hz.

+The following example illustrates the case where the offerer cannot receive more than 64 kbit/s.

 </t>

<t>

-If for some reason the offerer has bandwidth limitations, the client

-may use the "b=" header, as explained in SDP <xref target="rfc2327"></xref>. The following example

-illustrates the case where the offerer cannot receive more than

-64 kbit/s.

-</t>

-<t>

 <vspace blankLines="1" />

 <list style="empty">

 <t>m=audio 8088 RTP/AVP 97</t>

@@ -483,61 +513,26 @@

 payload types that may be proposed in the media line ("m=").

 </t>

-<t>

-An other way to make recommendations to the remote CELT encoder

-is to use its specific parameters via the a=fmtp: directive.  The

-following parameters are defined for use in this way:

-</t>

-<t>

-<vspace blankLines="1" />

-<list style="empty">

-<t>frame-samples: duration of each frame in samples (default is 256).<vspace blankLines="1" />

-</t>

-<t>nb-frames: number of frames per packet (default is 1).<vspace blankLines="1" /></t>

+<t>The following example demonstrates the use of the a=fmtp: parameters:</t>

-<t>max-size: maximum number of bytes of compressed data per CELT frame. <vspace blankLines="1" /></t>

-<t>mapping: Optional string describing the multi-channel mapping. <vspace blankLines="1" /></t>

-</list>

-</t>

-<t>Examples:</t>

<t>

 <vspace blankLines="1" />

 <list style="empty">

    	<t>m=audio 8008 RTP/AVP 97</t>

 	<t>a=rtpmap:97 CELT/44100</t>

-	<t>a=fmtp:97 frame-samples=512;nb-frames=2;max-size=100</t>

+	<t>a=fmtp:97 frame-size=512;nb-frames=2;</t>

 </list>

 </t>

<t>

 This examples illustrate an offerer that wishes to receive

-a CELT stream at 44100 Hz, by packing two 512-sample frames in each packet

-which is limited to a total of 201 bytes of payload.

+a CELT stream at 44100 Hz, by packing two 512-sample frames in each packet.

 </t>

-<t>

-Several CELT specific parameters can be given in a single

-a=fmtp line provided that they are separated by a semi-colon.

-</t>

-<t>

-The selected frame-samples value MUST be even. It SHOULD be divisible by 8

-and have a prime factorization which consists only 2, 3, or 5 factors.

-For example, powers-of-two and values such as 160, 320, 240, and 480 are

-recommended. Implementations SHOULD support receiving and sending the default

-value of 256, and if the size 256 is supported it MUST be offered.

-</t>

-<t>

-Care must be taken when setting the value of max-size and nb-frames so that the

-RTP packet size does not exceed the path MTU.

-</t>

 </section>

@@ -764,6 +759,40 @@

 </front>

 <seriesInfo name="RFC" value="3534" />

 </reference>

+<reference anchor="rfc3711">

+<front>

+<title>The Secure Real-time Transport Protocol (SRTP)</title>

+<author initials="M." surname="Baugher" fullname=""><organization/></author>

+<author initials="D." surname="McGrew" fullname=""><organization/></author>

+<author initials="M." surname="Naslund" fullname=""><organization/></author>

+<author initials="E." surname="Carrara" fullname=""><organization/></author>

+<author initials="K." surname="Norrman" fullname=""><organization/></author>

+<date month="March" year="2004" />

+</front>

+<seriesInfo name="RFC" value="3711" />

+</reference>

+<reference anchor="rfc4301">

+<front>

+<title>Security Architecture for the Internet Protocol</title>

+<author initials="S." surname="Kent" fullname=""><organization/></author>

+<author initials="K." surname="Seo" fullname=""><organization/></author>

+<date month="December" year="2005" />

+</front>

+<seriesInfo name="RFC" value="4301" />

+</reference>

+<reference anchor="rfc5246">

+<front>

+<title>The Transport Layer Security (TLS) Protocol Version 1.2</title>

+<author initials="T." surname="Dierks" fullname=""><organization/></author>

+<author initials="E." surname="Rescorla" fullname=""><organization/></author>

+<date month="August" year="2008" />

+</front>

+<seriesInfo name="RFC" value="5246" />

+</reference>

 </references>