| Table of content frame.
The purpose of "CTOC" frames is to allow a table of contents to be
defined. In the simplest case, a single "CTOC" frame can be used to
provide a flat (single-level) table of contents. However, multiple
"CTOC" frames can also be used to define a hierarchical (multi-level)
table of contents.
There may be more than one frame of this type in a tag but each must
have an Element ID that is unique with respect to any other "CTOC" or
"CHAP" frame in the tag.
Each "CTOC" frame represents one level or element of a table of contents
by providing a list of Child Element IDs. These match the Element IDs of
other "CHAP" and "CTOC" frames in the tag.
| <ID3v2.3 or ID3v2.4 frame header, ID: "CTOC"> | | (10 bytes) |
| Element ID | <text string> $00 |
| Flags | %000000ab |
| Entry count | $xx (8-bit unsigned int) |
| <Child Element ID list> |
| <Optional embedded sub-frames> |
The Element ID uniquely identifies the frame. It is not intended to
be human readable and should not be presented to the end-user.
Flag a - Top-level bit
This is set to 1 to identify the top-level "CTOC" frame. This frame
is the root of the Table of Contents tree and is not a child of any
other "CTOC" frame. Only one "CTOC" frame in an ID3v2 tag can have
this bit set to 1. In all other "CTOC" frames this bit shall be set
to 0.
Flag b - Ordered bit
This should be set to 1 if the entries in the Child Element ID list
are ordered or set to 0 if they not are ordered. This provides a hint
as to whether the elements should be played as a continuous ordered
sequence or played individually.
The Entry count is the number of entries in the Child Element ID list
that follows and must be greater than zero. Each entry in the list
consists of:
| Child Element ID | | <text string> $00 |
The last entry in the child Element ID list is followed by a sequence
of optional frames that are embedded within the "CTOC" frame and which
describe this element of the table of contents (e.g. a "TIT2" frame
representing the name of the element) or provide related material such
as URLs and images. These sub-frames are contained within the bounds
of the "CTOC" frame as signalled by the size field in the "CTOC"
frame header.
If a parser does not recognise "CTOC" frames it can skip them using
the size field in the frame header. When it does this it will skip
any embedded sub-frames carried within the frame.
For more details, please refer to the ID3 Chapter Frame specifications:
| 