VorbisRTP

From XiphWiki

(Difference between revisions)
Jump to: navigation, search
(Replace draft links with RFC links.)
 
(11 intermediate revisions not shown)
Line 3: Line 3:
This page documents current consensus on the RTP payload format for Vorbis audio. This encapsulation is useful for interactive and multicast streaming.
This page documents current consensus on the RTP payload format for Vorbis audio. This encapsulation is useful for interactive and multicast streaming.
-
=== Drafts ===
+
=== Standard ===
-
[http://svn.xiph.org/tags/vorbis/libvorbis-1.1.0/doc/draft-kerr-avt-vorbis-rtp-03.txt draft-kerr-avt-vorbis-rtp-03] (now expired) was the last spec attempt and serves as the baseline for current work.
+
In 2008, the Vorbis RTP specification was accepted by the IETF's Network Working Group as RFC 5215. It may be found at
-
 
+
*[http://tools.ietf.org/rfc/rfc5215.txt rfc5215.txt]
-
Version 04 of the draft is being written using the XML markup defined in [http://xml.resource.org/public/rfc/html/rfc2629.html RFC2629]. Text and HTML versions of the current draft state are available here:
+
*[http://xiph.org/vorbis/doc/rfc5215.xml rfc5215.xml]
-
 
+
-
* [http://www.j-ogg.de/rfc/vorbis-rtp.txt draft-kerr-avt-vorbis-rtp-04.txt]
+
-
* [http://www.j-ogg.de/rfc/vorbis-rtp.html draft-kerr-avt-vorbis-rtp-04.html]
+
=== Issues ===
=== Issues ===
Line 32: Line 29:
=== Implementation ===
=== Implementation ===
-
Tor-Einar Jarnbjo has an [http://www.j-ogg.de/rtp/index.html example implementation] that extends the ideas in the 03 draft a bit.
+
Tor-Einar Jarnbjo has an [http://www.j-ogg.de/rtp/index.html example implementation] that extends the ideas in the kerr 03 draft a bit.
-
<div style="overflow:auto; height: 1px; ">
+
 
-
[http://21jewelry.com Fine Jewelry]
+
[[Category:Vorbis]]
-
[http://mrjeweller.us Gold Jewelry]
+
-
[http://detox-kit.com Drug detox]
+
-
[http://detox-kit.com/categories/marijuana-detox/ Marijuana detox]
+
-
[http://detox-kit.com/categories/detox-drinks/ Detox Drinks]
+
-
[http://detox-kit.com/categories/saliva-detox/ saliva drug detox]
+
-
[http://detox-kit.com/categories/saliva-detox/ saliva detox]
+
-
[http://detox-kit.com/categories/hair-detox/ hair detox]
+
-
[http://detox-kit.com/categories/hair-detox/ hair drug detox]
+
-
[http://tests-market.com/categories/first-aid/ first aid kit]
+
-
[http://tests-market.com/categories/drug-tests/ drug test]
+
-
[http://tests-market.com/categories/alcohol-tests/ alcohol test]
+
-
[http://tests-market.com/categories/ovulation-tests/ ovulation test]
+
-
[http://mrjeweller.us/categories/earrings/ earrings]
+
-
[http://mrjeweller.us/categories/earrings/ gold earrings]
+
-
[http://mrjeweller.us/categories/pearl-earrings/ pearl earrings]
+
-
[http://mrjeweller.us/categories/anklets/ anklet]
+
-
[http://mrjeweller.us/categories/anklets/ anklets]
+
-
[http://mrjeweller.us/categories/belly-piercings/ belly piercings]
+
-
[http://mrjeweller.us/categories/belly-piercings/ belly piercing]
+
-
[http://mrjeweller.us/categories/birthstones/ birthstone]
+
-
[http://mrjeweller.us/categories/birthstones/ birthstones]
+
-
[http://mrjeweller.us/categories/bracelets/ bracelets]
+
-
[http://mrjeweller.us/categories/bracelets/ bracelet]
+
-
[http://mrjeweller.us/categories/bracelets/ gold bracelet]
+
-
[http://mrjeweller.us/categories/bangle-bracelets/ bangle bracelet]
+
-
[http://mrjeweller.us/categories/rope-bracelets/ rope bracelets]
+
-
[http://mrjeweller.us/categories/rope-bracelets/ rope bracelet]
+
-
[http://mrjeweller.us/categories/chains/ gold chains]
+
-
[http://mrjeweller.us/categories/chains/ gold chain]
+
-
[http://mrjeweller.us/categories/beaded-chains/ beaded chains]
+
-
[http://mrjeweller.us/categories/charms/ charms]
+
-
[http://mrjeweller.us/categories/diamond-pendants/ diamond pendants]
+
-
[http://mrjeweller.us/categories/diamond-pendants/ diamond pendant]
+
-
[http://mrjeweller.us/categories/cubic-zirconia/ cubic zirconia jewelry]
+
-
[http://mrjeweller.us/categories/mens-bracelets/ men's bracelet]
+
-
[http://mrjeweller.us/categories/mens-rings/ men's ring]
+
-
[http://mrjeweller.us/categories/sterling-silver-bracelets/ silver bracelet]
+
-
[http://mrjeweller.us/categories/sterling-silver-chains/ silver chains]
+
-
[http://toe.shengen.ru toe rings]
+
-
[http://detox.shengen.ru drug detox]
+
-
[http://jewelry.shengen.ru fine gold jewelry]
+
-
</div>
+

Latest revision as of 14:46, 19 September 2008

Contents

Vorbis over RTP

This page documents current consensus on the RTP payload format for Vorbis audio. This encapsulation is useful for interactive and multicast streaming.

Standard

In 2008, the Vorbis RTP specification was accepted by the IETF's Network Working Group as RFC 5215. It may be found at

Issues

Basically, we pack Vorbis packets into RTP packets; that's been part of the draft for some time. The hard part is achieving reliable header transmission, since RTP is usually used in combination with a no-guaranteed-delivery networking mechanism. Equally important, in multicast the headers can't be prepended on connection the way icecast does with HTTP streams.

The current suggestion (due to Jack) is that we dispense with the chaining feature of Ogg streams, and only allow a single set of vorbis headers per RTP stream. Since RTP is most often used to stream live or at least individual events, this is not a serious limitation. Even in the "simulated live" case encoded files often have the same set of codebooks, and those that do not can be re-encoded on the fly.

The only real drawback is the loss of a metadata update mechanism. This can be resolved either by using a completely separate metadata stream (which we've always wanted to do anyway) or by altering the spec to allow comment header packets to occur outside the headers. In the later case a recording application would need to insert chaining boundaries and duplicate headers at each metadata change. The former offers the client more control over the metadata stream bandwidth.

Design

  • Vorbis packets get packed into RTP packets
  • Header parameters are fixed per stream, so they can be passed in the SDP
 * inline in the SDP?
 * HTTP reference or other protocol?
 * some kind of hash so clients can cache codebooks/parameters
 * inline in the RTP stream should also be allowed
  • Granulepos becomes timestamp (still in samples)

Implementation

Tor-Einar Jarnbjo has an example implementation that extends the ideas in the kerr 03 draft a bit.

Personal tools


Main Page

Xiph.Org Projects

Audio—

Video—

Text—

Container—

Streaming—