From ba15707b292d827bdce732e7713b26fae3f75c74 Mon Sep 17 00:00:00 2001 From: Alex Bennee Date: Wed, 14 Jul 2010 15:57:06 +0100 Subject: EasyTag 2.1.1 --- doc/vorbis/v-comment.html | 194 ++++++++++++++++++++++++++++++++++++++++++++++ doc/vorbis/white-ogg.png | Bin 0 -> 1181 bytes 2 files changed, 194 insertions(+) create mode 100755 doc/vorbis/v-comment.html create mode 100755 doc/vorbis/white-ogg.png (limited to 'doc/vorbis') diff --git a/doc/vorbis/v-comment.html b/doc/vorbis/v-comment.html new file mode 100755 index 0000000..4089d81 --- /dev/null +++ b/doc/vorbis/v-comment.html @@ -0,0 +1,194 @@ +xiph.org: Ogg Vorbis documentation + +

+ + +

+Ogg Vorbis comment field specification +

+ +Last update to this document: January 19, 2001

+ +The text comment header is the second (of three) header packets that +begin a Vorbis bitstream. It is meant for short, text comments, +not arbitrary metadata; arbitrary metadata belongs in a +metadata stream (usually an XML stream type).

+ +

Comment use rationale

+ +The comment field is meant to be used much like someone jotting a +quick note on the bottom of a CDR. It should be a little information to +remember the disc by and explain it to others; a short, to-the-point +text note that need not only be a couple words, but isn't going to be +more than a short paragraph. The essentials, in other words, whatever +they turn out to be, eg: + +

+"Honest Bob and the Factory-to-Dealer-Incentives, _I'm Still Around_, +opening for Moxy Fruvous, 1997" +

+ +

Structure

+ +The comment header logically is a list of eight-bit-clean vectors; the +number of vectors is bounded to 2^32-1 and the length of each vector +is limited to 2^32-1 bytes. The vector length is encoded; the vector +is not null terminated. In addition to the vector list, there is a +single vector for vendor name (also 8 bit clean, length encoded in 32 +bits). Libvorbis currently sets the vendor string to "Xiphophorus +libVorbis I 20010119".

+ +The comment vectors are structured similarly to a UNIX environment. +That is, comment fields consist of a field name and a field value and +look like: + +

+comment[0]="ARTIST=me"; 
+comment[1]="TITLE=the sound of vorbis"; 
+

+ +

Content vector format

+ +

A case-insensitive field name that may consist of ASCII 0x20 through +0x7D, 0x3D ('=') excluded. ASCII 0x41 through 0x5A inclusive (A-Z) is +to be considered equivalent to ASCII 0x61 through 0x7A inclusive +(a-z). + +
The field name is immediately followed by ASCII 0x3D ('='); this +equals sign is used to terminate the field name. + +
0x3D is followed by 8 bit clean UTF-8 field contents to the end of +the field. +

+ +

Field names

+ +Below is a proposed, minimal list of standard filed names with a +description of intended use. No single or group of field names is +mandatory; a comment header may contain one, all or none of the names +in this list. +

TITLE: Track name + +
VERSION: The version field may be used to differentiate multiple +version of the same track title in a single collection. (e.g. remix info) + +
ALBUM: The collection name to which this track belongs + +
TRACKNUMBER: The track number of this piece if part of a specific larger collection or album + +
ARTIST: Track performer + +
ORGANIZATION: Name of the organization producing the track (i.e. +the 'record label') + +
DESCRIPTION: A short text description of the contents + +
GENRE: A short text indication of music genre + +
DATE: Date the track was recorded + +
LOCATION: Location where track was recorded + +
COPYRIGHT: Copyright information + +
ISRC: ISRC number for the track; see the ISRC intro page for more information on ISRC numbers. + +

+ +

Implications

+Field names should not be 'internationalized'; this is a +concession to simplicity not an attempt to exclude the majority of +the world that doesn't speak English. Field *contents*, however, +are represented in UTF-8 to allow easy representation of any language. +
+We have the length of the entirety of the field and restrictions on +the field name so that the field name is bounded in a known way. Thus +we also have the length of the field contents. +
+Individual 'vendors' may use non-standard field names within +reason. The proper use of comment fields should be clear through +context at this point. Abuse will be discouraged. +
+There is no vendor-specific prefix to 'nonstandard' field names. +Vendors should make some effort to avoid arbitrarily polluting the +common namespace. +
+Field names are not required to be unique (occur once) within a +comment header. As an example, assume a track was recorded by three +well know artists; the following is permissible, and encouraged: +
```
+              ARTIST=Dizzy Gillespie 
+              ARTIST=Sonny Rollins 
+              ARTIST=Sonny Stitt 
+
```
+ +

+ +

Encoding

+ +The comment header comprises the entirety of the second bitstream +header packet. Unlike the first bitstream header packet, it is not +generally the only packet on the second page and may not be restricted +to within the second bitstream page. The length of the comment header +packet is [practically] unbounded. The comment header packet is not +optional; it must be present in the bitstream even if it is +effectively empty.

+ +The comment header is encoded as follows (as per Ogg's standard +bitstream mapping which renders least-significant-bit of the word to be +coded into the least significant available bit of the current +bitstream octet first): + +

+Vendor string length (32 bit unsigned quantity specifying number of octets) + +
+Vendor string ([vendor string length] octets coded from beginning of string to end of string, not null terminated) + +
Number of comment fields (32 bit unsigned quantity specifying number of fields) + +
Comment field 0 length (if [Number of comment fields]>0; 32 bit unsigned quantity specifying number of octets) + +
+Comment field 0 ([Comment field 0 length] octets coded from beginning of string to end of string, not null terminated) + +
Comment field 1 length (if [Number of comment fields]>1...)... +

+ +This is actually somewhat easier to describe in code; implementation of the above can be found in vorbis/lib/info.c:_vorbis_pack_comment(),_vorbis_unpack_comment() + +

+ +

+ + + +Ogg is a Xiphophorus effort to +protect essential tenets of Internet multimedia from corporate +hostage-taking; Open Source is the net's greatest tool to keep +everyone honest. See About +Xiphophorus for details. +

+ +Ogg Vorbis is the first Ogg audio CODEC. Anyone may +freely use and distribute the Ogg and Vorbis specification, +whether in a private, public or corporate capacity. However, +Xiphophorus and the Ogg project (xiph.org) reserve the right to set +the Ogg/Vorbis specification and certify specification compliance.

+ +Xiphophorus's Vorbis software CODEC implementation is distributed +under the Lesser/Library GNU Public License. This does not restrict +third parties from distributing independent implementations of Vorbis +software under other licenses.

+ + + diff --git a/doc/vorbis/white-ogg.png b/doc/vorbis/white-ogg.png new file mode 100755 index 0000000..45dc0ac Binary files /dev/null and b/doc/vorbis/white-ogg.png differ -- cgit v1.2.3