[xiph-commits] r11572 - trunk/theora/doc
lu_zero at svn.xiph.org
lu_zero at svn.xiph.org
Wed Jun 14 06:05:33 PDT 2006
Author: lu_zero
Date: 2006-06-14 06:05:28 -0700 (Wed, 14 Jun 2006)
New Revision: 11572
Modified:
trunk/theora/doc/draft-barbato-avt-rtp-theora-00.xml
Log:
Update with some cosmetics applied
Modified: trunk/theora/doc/draft-barbato-avt-rtp-theora-00.xml
===================================================================
--- trunk/theora/doc/draft-barbato-avt-rtp-theora-00.xml 2006-06-14 06:44:33 UTC (rev 11571)
+++ trunk/theora/doc/draft-barbato-avt-rtp-theora-00.xml 2006-06-14 13:05:28 UTC (rev 11572)
@@ -6,7 +6,7 @@
<rfc ipr="full3978" docName="RTP Payload Format for Theora Encoded Video">
<front>
-<title>draft-barbato-avt-rtp-theora-00</title>
+<title>draft-barbato-avt-rtp-theora-01</title>
<author initials="L" surname="Barbato" fullname="Luca Barbato">
<organization>Xiph.Org</organization>
@@ -16,8 +16,7 @@
</address>
</author>
-<date day="24" month="February" year="2006" />
-
+<date day="16" month="June" year="2006" />
<area>General</area>
<workgroup>AVT Working Group</workgroup>
<keyword>I-D</keyword>
@@ -28,7 +27,7 @@
<abstract>
<t>
-This document describes a RTP payload format for transporting Theora encoded video. It details the RTP encapsulation mechanism for raw Theora data and configuration headers necessary to configure the decoder.
+This document describes a RTP payload format for transporting Theora encoded video. It details the RTP encapsulation mechanism for raw Theora data and configuration headers necessary to configure the decoder.
</t>
<t>
@@ -49,24 +48,23 @@
<section anchor="Introduction" title="Introduction">
<t>
-Theora is a general purpose, lossy video codec. It is based on the VP3 video codec produced by On2 Technologies and has been donated to the Xiph.org Foundation.
-</t>
+Theora is a general purpose, lossy video codec. It is based on the VP3 video codec produced by On2 Technologies and has been donated to the Xiph.org Foundation.</t>
<t>
-Theora I is a block-based lossy transform codec that utilizes an 8 x 8 Type-II Discrete Cosine Transform and block-based motion compensation. This places it in the same class of codecs as MPEG-1, MPEG-2, MPEG-4, and H.263. The details of how individual blocks are organized and how DCT coefficients are stored in the bitstream differ substantially from these codecs, however. Theora supports only intra frames (I frames in MPEG) and inter frames (P frames in MPEG).
+Theora I is a block-based lossy transform codec that utilizes an 8 x 8 Type-II Discrete Cosine Transform and block-based motion compensation. This places it in the same class of codecs as MPEG-1, MPEG-2, MPEG-4, and H.263. The details of how individual blocks are organized and how DCT coefficients are stored in the bitstream differ substantially from these codecs, however. Theora supports only intra frames (I frames in MPEG) and inter frames (P frames in MPEG).
</t>
<t>
-Theora provides none of its own framing, synchronization, or protection against transmission errors. Instead, the codec expects to receive a discrete sequence of data packets. Theora is a free-form variable bit rate (VBR) codec, and these packets have no minimum size, maximum size, or fixed/expected size. Theora packets are thus intended to be used with a transport mechanism that provides free-form framing, synchronization, positioning, and error correction in accordance with these design assumptions, such as Ogg <xref target="rfc3533"></xref> or RTP/AVP <xref target="rfc3550"></xref>.
+Theora provides none of its own framing, synchronization, or protection against transmission errors. Instead, the codec expects to receive a discrete sequence of data packets. Theora is a free-form variable bit rate (VBR) codec, and these packets have no minimum size, maximum size, or fixed/expected size. Theora packets are thus intended to be used with a transport mechanism that provides free-form framing, synchronization, positioning, and error correction in accordance with these design assumptions, such as Ogg <xref target="rfc3533"></xref> or RTP/AVP <xref target="rfc3550"></xref>.
</t>
<t>
Theora I currently supports progressive video data of arbitrary dimensions at a constant frame rate in one of several Y'CbCr color spaces.
-Three different chroma subsampling formats are supported: 4:2:0, 4:2:2, and 4:4:4. The Theora I format does not support interlaced material, variable frame rates, bit-depths larger than 8 bits per component, nor alternate color spaces such as RGB or arbitrary multi-channel spaces. Black and white content can be efficiently encoded, however, because the uniform chroma planes compress well. Arbitrary frame size will be encoded rounding to the upper multiple of 16 both dimension for performance reason. The original width and height will be encoded in the header and the decoder will use this information to clip the decoded frame to the right dimensions.
+Three different chroma subsampling formats are supported: 4:2:0, 4:2:2, and 4:4:4. The Theora I format does not support interlaced material, variable frame rates, bit-depths larger than 8 bits per component, nor alternate color spaces such as RGB or arbitrary multi-channel spaces. Black and white content can be efficiently encoded, however, because the uniform chroma planes compress well. Arbitrary frame size will be encoded rounding to the upper multiple of 16 both dimension for performance reason. The original width and height will be encoded in the header and the decoder will use this information to clip the decoded frame to the right dimensions.
</t>
<t>
-Theora is similar to the Vorbis audio <xref target="vorbisrtp"></xref> in that it the decoder reads the probability model for the entropy coder and all quantization parameters from special "header" packets at the start of the compressed data. It is therefore impossible to decode any video data without having previously fetched the codec info and codec setup headers, although Theora can initiate decode at an arbitrary intra-frame packet so long as the codec has been initialized with the associated headers.
+Theora is similar to the Vorbis audio <xref target="vorbisrtp"></xref> in that it the decoder reads the probability model for the entropy coder and all quantization parameters from special "header" packets at the start of the compressed data. It is therefore impossible to decode any video data without having previously fetched the codec info and codec setup headers, although Theora can initiate decode at an arbitrary intra-frame packet so long as the codec has been initialized with the associated headers.
</t>
<section anchor="Terminology" title="Terminology">
@@ -128,7 +126,7 @@
<t>
Extension (X): 1 bit</t><t>
-The Extension bit is used in accordance with <xref target="rfc3550"></xref>.
+The Extension bit is used in accordance with <xref target="rfc3550"></xref>.
</t>
<t>
@@ -158,8 +156,7 @@
<t>
SSRC/CSRC identifiers: </t><t>
-These two fields, 32 bits each with one SSRC field and a maximum of 16 CSRC fields, are as defined in
-<xref target="rfc3550"></xref>.
+These two fields, 32 bits each with one SSRC field and a maximum of 16 CSRC fields, are as defined in <xref target="rfc3550"></xref>.
</t>
</section>
@@ -185,7 +182,7 @@
<t>
Configuration Ident: 24 bits</t>
<t>
-This 24 bit field is used to associate the Theora data to a decoding Packed Configuration.
+This 24 bit field is used to associate the Theora data to a decoding Packed Configuration.
</t>
<t>
@@ -222,7 +219,7 @@
<t>
-The last 4 bits represent the number of complete packets in this payload. This provides for a maximum number of 15 Theora packets in the payload. If the packet contains fragmented data the number of packets MUST be set to 0.
+The last 4 bits represent the number of complete packets in this payload. This provides for a maximum number of 15 Theora packets in the payload. If the packet contains fragmented data the number of packets MUST be set to 0.
</t>
</section>
@@ -244,7 +241,7 @@
</figure>
<t>
-The Theora codec uses relatively unstructured raw packets containing binary integer fields of arbitrary width that often do not fall on an octet boundary. When a Theora encoder produces packets, unused space in the last byte of a packet is always zeroed during the encoding process. Thus, should this unused space be read, it will return binary zeros.
+The Theora codec uses relatively unstructured raw packets containing binary integer fields of arbitrary width that often do not fall on an octet boundary. When a Theora encoder produces packets, unused space in the last byte of a packet is always zeroed during the encoding process. Thus, should this unused space be read, it will return binary zeros.
</t>
<t>
@@ -325,7 +322,7 @@
</t>
<t>
-The delivery vectors in use are specified by an SDP attribute to indicate the method and the optional URI where the Vorbis <xref target="Packed Configuration">Packed Configuration</xref> Packets could be fetched. Different delivery methods MAY be advertised for the same session. The in-band codebook delivery SHOULD be considered as baseline, out-of-band delivery methods that don't use RTP will not be described in this document. For non chained streams, the Configuration delivery method RECOMMENDED is inline the <xref target="Packed Configuration">Packed Configuration</xref> in the SDP as explained in the <xref target="Mapping MIME Parameters into SDP"> IANA considerations</xref>
+The delivery vectors in use are specified by an SDP attribute to indicate the method and the optional URI where the Theora <xref target="Packed Configuration">Packed Configuration</xref> Packets could be fetched. Different delivery methods MAY be advertised for the same session. The in-band codebook delivery SHOULD be considered as baseline, out-of-band delivery methods that don't use RTP will not be described in this document. For non chained streams, the Configuration delivery method RECOMMENDED is inline the <xref target="Packed Configuration">Packed Configuration</xref> in the SDP as explained in the <xref target="Mapping MIME Parameters into SDP"> IANA considerations</xref>
</t>
<t>
@@ -581,9 +578,8 @@
</section>
-
-
</section>
+
<section anchor="Comment Headers" title="Comment Headers">
<t>
@@ -903,7 +899,7 @@
<t>The mandated parameters "delivery-method" and "configuration" MUST be included in the SDP "a=fmpt" attribute.</t>
<vspace blankLines="1" />
-<t>The optional parameter "configuration-uri", when present, MUST be included in the SDP "a=fmpt" attribute and MUST follow the delivery-method that applies.</t>
+<t>The optional parameter "configuration-uri", when present, MUST be included in the SDP "a=fmpt" attribute and MUST follow the delivery-method that applies.</t>
</list>
@@ -926,7 +922,7 @@
</list>
</section>
-</section>
+</section>
<section anchor="Usage with the SDP Offer/Answer Mode" title="Usage with the SDP Offer/Answer Model">
@@ -1014,7 +1010,7 @@
<author initials="S." surname="Bradner" fullname="Scott Bradner"></author>
</front>
<seriesInfo name="RFC" value="2119" />
-</reference>
+</reference>
<reference anchor="rfc3550">
<front>
@@ -1044,8 +1040,8 @@
<author initials="H." surname="Schulzrinne" fullname="Henning Schulzrinne"></author>
</front>
<seriesInfo name="RFC" value="3264" />
-</reference>
-
+</reference>
+
<reference anchor="rfc2327">
<front>
<title>SDP: Session Description Protocol</title>
@@ -1053,7 +1049,7 @@
<author initials="V." surname="Jacobson" fullname="Van Jacobson"></author>
</front>
<seriesInfo name="RFC" value="2327" />
-</reference>
+</reference>
<reference anchor="rfc1063">
<front>
@@ -1061,7 +1057,7 @@
<author initials="J." surname="Mogul et al." fullname="J. Mogul et al."></author>
</front>
<seriesInfo name="RFC" value="1063" />
-</reference>
+</reference>
<reference anchor="rfc1981">
<front>
@@ -1069,7 +1065,7 @@
<author initials="J." surname="McCann et al." fullname="J. McCann et al."></author>
</front>
<seriesInfo name="RFC" value="1981" />
-</reference>
+</reference>
<reference anchor="rtcp-feedback">
<front>
@@ -1081,7 +1077,7 @@
<author initials="J." surname="Rey" fullname="Jose Rey"></author>
</front>
<seriesInfo name="Internet Draft" value="(draft-ietf-avt-rtcp-feedback-11: Work in progress)" />
-</reference>
+</reference>
<reference anchor="vorbisrtp">
<front>
@@ -1089,7 +1085,7 @@
<author initials="L." surname="Barbato" fullname="Luca Barbato"></author>
</front>
<seriesInfo name="Internet Draft" value="(Work in progress)" />
-</reference>
+</reference>
<reference anchor="rfc3548">
<front>
@@ -1137,7 +1133,7 @@
<front>
<title>Theora I specification: Codec setup and packet decode. http://www.xiph.org/theora/doc/Theora_I_spec.pdf</title>
</front>
-</reference>
+</reference>
<reference anchor='rfc3611'>
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