Commit f3d6c7a3 authored by Jean-Marc Valin's avatar Jean-Marc Valin

Update Opus RTP payload

Addresses comments from several months ago
parent 8dc91de1
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
<!ENTITY rfc2119 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml'>
<!ENTITY rfc3389 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3389.xml'>
<!ENTITY rfc3550 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3550.xml'>
<!ENTITY rfc3711 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3711.xml'>
<!ENTITY rfc3551 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3551.xml'>
......@@ -17,7 +18,7 @@
<!ENTITY nbsp "&#160;">
]>
<rfc category="std" ipr="trust200902" docName="draft-ietf-payload-rtp-opus-01">
<rfc category="std" ipr="trust200902" docName="draft-ietf-payload-rtp-opus-02">
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<?rfc strict="yes" ?>
......@@ -60,17 +61,17 @@
<organization>Mozilla</organization>
<address>
<postal>
<street>650 Castro Street</street>
<city>Mountain View</city>
<street>2 Harrison Street</street>
<city>San Francisco</city>
<region>CA</region>
<code>94041</code>
<code>94105</code>
<country>USA</country>
</postal>
<email>jmvalin@jmvalin.ca</email>
</address>
</author>
<date day='14' month='January' year='2014' />
<date day='30' month='June' year='2014' />
<abstract>
<t>
......@@ -189,7 +190,7 @@
The bitrate can be changed dynamically within that range.
All
other parameters being
equal, higher bitrate results in higher quality.
equal, a higher bitrate results in higher quality.
</t>
<section title='Recommended Bitrate' anchor='bitrate_by_bandwidth'>
<t>
......@@ -247,14 +248,22 @@
the Opus encoder may be set to use discontinuous
transmission (DTX), where parts of the encoded signal that
correspond to periods of silence in the input speech or audio signal
are not transmitted to the receiver.
are not transmitted to the receiver. A receiver can distinguish
between DTX and packet loss by looking for gaps in the sequence
number, as described by Section 4.1
of&nbsp;<xref target="RFC3551"/>.
</t>
<t>
On the receiving side, the non-transmitted parts will be handled by a
frame loss concealment unit in the Opus decoder which generates a
comfort noise signal to replace the non transmitted parts of the
speech or audio signal.
speech or audio signal. Use of <xref target="RFC3389"/> Comfort
Noise (CN) with Opus is discouraged.
The transmitter MUST drop whole frames only,
based on the size of the last transmitted frame,
to ensure successive RTP timestamps differ by a multiple of 120 and
to allow the receiver to use whole frames for concealment.
</t>
<t>
......@@ -346,8 +355,9 @@
therefore no padding is required. The payload MAY be padded by an
integer number of octets according to <xref target="RFC3550"/>.</t>
<t>The marker bit (M) of the RTP header is used in accordance with
Section 4.1 of <xref target="RFC3551"/>.</t>
<t>The timestamp, sequence number, and marker bit (M) of the RTP header
are used in accordance with Section 4.1
of&nbsp;<xref target="RFC3551"/>.</t>
<t>The RTP payload type for Opus has not been assigned statically and is
expected to be assigned dynamically.</t>
......@@ -914,6 +924,7 @@
<back>
<references title="Normative References">
&rfc2119;
&rfc3389;
&rfc3550;
&rfc3711;
&rfc3551;
......
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