This
specification
describes
the
requirements
for
the
creation
of
audiobooks,
using
a
profile
of
the
Publication
Manifest
specification.
Status
of
This
Document
This
is
a
preview
Do
not
attempt
to
implement
this
version
of
the
specification.
Do
not
reference
this
version
as
authoritative
in
any
way.
Instead,
see
https://w3c.github.io/audiobooks/
for
the
Editor's
draft.
This
section
describes
the
status
of
this
document
at
the
time
of
its
publication.
A
list
of
current
W3C
publications
and
the
latest
revision
of
this
technical
report
can
be
found
in
the
W3C
technical
reports
index
at
https://www.w3.org/TR/.
Publication
as
an
Editor's
Draft
does
not
imply
endorsement
by
W3C
and
its
Members.
This
is
a
draft
document
and
may
be
updated,
replaced
or
obsoleted
by
other
documents
at
any
time.
It
is
inappropriate
to
cite
this
document
as
other
than
work
in
progress.
Future
updates
to
this
specification
may
incorporate
new
features
.
An
Audiobook
is
a
collection
of
audio
resources
grouped
together
by
a
reading
order,
metadata,
and
resources,
all
contained
in
a
manifest.
This
Audiobook
can
live
on
the
Open
Web
Platform,
or
as
a
packaged
entity.
This
specification
is
intended
to
standardize
the
audiobooks
distribution
model
on
the
web
and
between
businesses.
It
should
facilitate
different
user
agent
architectures
for
the
consumption
of
Audiobooks.
The
primary
goal
is
to
bring
clarity
to
a
part
of
the
publishing
industry
currently
underserved
by
standards,
while
opening
Audiobooks
to
the
Open
Web
Platform
and
new
user
agents.
This
specification
does
not
outline
what
file
types
or
formats
should
be
used
by
content
creators,
only
a
manifest
format
for
delivering
them.
This
specification
does
not
define
how
user
agents
are
expected
to
render
Audiobooks.
Details
about
the
types
of
affordances
that
user
agents
can
provide
to
enhance
the
reading
experience
for
users
are
instead
defined
in
[
pwp-ucr
].
2.
Terminology
Terms
with
meanings
specific
to
the
publishing
industry
are
capitalized
in
this
document
(e.g.,
"Reading
System").
A
complete
list
of
these
terms
and
definitions
is
provided
in
[
pub-manifest
].
Only
the
first
instance
of
a
term
in
a
section
is
linked
to
its
definition.
In
addition,
the
following
terminology
is
defined
for
use
in
this
specification:
Supplemental
Content
Supplemental
content
is
any
content
relating
to
the
audiobook
content
but
not
required
for
the
full
experience
of
the
publication.
Examples
of
supplemental
content
include
photographs,
charts,
or
data
relating
to
topics
mentioned
in
the
audiobook.
3.
Conformance
As
well
as
sections
marked
as
non-normative,
all
authoring
guidelines,
diagrams,
examples,
and
notes
in
this
specification
are
non-normative.
Everything
else
in
this
specification
is
normative.
The
key
words
MAY
,
MUST
,
MUST
NOT
,
RECOMMENDED
,
REQUIRED
,
and
SHOULD
in
this
document
are
to
be
interpreted
as
described
in
BCP
14
[
RFC2119
]
[
RFC8174
]
when,
and
only
when,
they
appear
in
all
capitals,
as
shown
here.
4.
Construction
4.1
Primary
Entry
Page
The
primary
entry
page
is
an
HTML
resource
that
represents
the
preferred
starting
resource
of
an
Audiobook
and
enables
discovery
of
its
manifest.
It
typically
introduces
the
audiobook
and
provides
access
to
the
content.
An
Audiobook
MUST
include
a
primary
entry
page
except
when
packaging
allows
alternative
discovery
of
the
manifest.
When
present,
the
page
MUST
be
included
in
the
resource
list
.
4.2
Table
of
Contents
The
table
of
contents
provides
a
hierarchical
list
of
links
that
reflects
the
structural
outline
of
the
major
sections
of
the
Audiobook
and
any
supplemental
content
it
may
contain.
The
table
of
contents
is
expressed
via
an
[
html
]
element
(typically
a
nav
element)
in
one
of
the
resources.
This
element
MUST
be
identified
by
the
role
attribute
[
html
]
value
"doc-toc"
[
dpub-aria-1.0
].
If
the
table
of
contents
is
located
in
the
primary
entry
page
,
the
table
of
contents
MUST
be
the
first
element
in
the
document
—
in
document
tree
order
[
dom
]
—
with
that
role
value.
Otherwise,
the
manifest
SHOULD
identify
the
resource
that
contains
the
structure.
If
the
table
of
contents
is
not
located
in
the
primary
entry
page
,
the
manifest
SHOULD
identify
the
resource
that
contains
the
structure.
When
an
Audiobook
contains
additional
audio
resources
(i.e.
that
include
multiple
chapters
or
parts,
or
if
the
audiobook
contains
supplemental
content):
content:
a
table
of
contents
SHOULD
be
included;
the
table
of
contents
SHOULD
include
a
link
to
any
of
the
resources
;
and
Some
Audiobooks
may
have
audio
resources
that
contain
more
than
one
chapter
or
section
of
the
book
content.
It
is
strongly
recommended
that
content
creators
provide
a
table
of
contents
using
media
fragments
[
media-frags
]
to
provide
the
user
with
access
to
the
structure
of
the
Audiobook.
Note
When
including
supplemental
content,
be
aware
that
users
might
not
have
access
to
this
content
unless
it
is
linked
to
from
the
table
of
contents.
It
is
strongly
advised
to
provide
links
to
all
content
that
is
not
in
the
default
reading
order.
The
Audiobook
manifest
is
defined
by
a
set
of
properties
that
describe
the
basic
information
a
user
agent
requires
to
process
and
render
an
Audiobook.
These
properties
are
categorized
in
the
Publication
Manifest
[
pub-manifest
].
Where
these
properties
are
extended
from
the
Publication
Manifest
is
specified
in
this
section.
Note
The
Audiobook
manifest
is
defined
as
a
specific
"shape"
of
[
json-ld11
].
This
shape
is
also
defined,
informally,
through
a
JSON
schema [
json-schema
]
that
expresses
the
constraints
defined
in
this
specification.
This
schema
is
maintained
at
https://www.w3.org/ns/pub-schema/audiobooks/
.
5.2
Requirements
The
requirements
for
the
expression
of
Audiobook
properties
and
resource
relations
are
defined
as
follows:
Note
The
list
of
properties
uses
the
formal
names
for
each
property
as
described
in
[
schema.org
]
and
[
pub-manifest
].
A
descriptive
label
is
included
in
parentheses
where
the
purpose
of
these
properties
might
be
unclear.
Some
properties
are
implicitly
required,
as
they
are
compiled
from
alternative
information
when
not
explicitly
authored.
Refer
to
the
internal
representation
data
models
[
pub-manifest
]
for
more
information
(the
Audiobooks
representation
only
differs
in
the
default
value
for
the
type
term).
5.3
Manifest
Contexts
An
Audiobook
manifest
has
to
start
by
setting
the
JSON-LD
context
[
json-ld
].
The
context
has
the
following
two
major
components:
To
add
the
global
language
and
direction
of
the
manifest
metadata,
language
and
direction
declaration
[
pub-manifest
]
can
also
be
added
to
the
context:
Example
2
:
Declaring
French
as
the
default
language
for
the
manifest
A
creator
is
an
individual
or
entity
responsible
for
the
creation
of
the
Audiobook.
The
Audiobooks
profile
can
use
the
full
list
of
creators
defined
in
[
pub-manifest
].
The
creators
list
includes
two
recommended
creators
for
Audiobooks:
A
duration
is
the
length
of
the
audio
resources
in
an
Audiobook.
The
duration
property
is
fully
defined
in
Publication
Manifest
[
pub-manifest
].
Duration
SHOULD
be
expressed
for
the
entirety
of
the
audiobook
as
part
of
the
manifest,
and
SHOULD
MUST
be
present
at
the
item
level
in
the
default
reading
order
.
Proposed
Correction
1.1
We
have
updated
the
normative
requirement
for
the
duration
property
on
the
item
level,
to
address
implementer
feedback
in
regards
to
facilitating
streaming.
This
normative
requirement
is
now
a
MUST
.
When
a
content
creator
specifies
both
the
duration
for
the
audiobook
and
item-level
duration
in
the
default
reading
order
the
resource-level
duration
SHOULD
be
equal
to
the
sum
of
the
durations
of
the
items
in
the
reading
order.
The
default
reading
order
MUST
contain
at
least
one
audio
resource,
which
MAY
be
identified
by
the
type
of
LinkedResource
[
pub-manifest
].
The
default
reading
order
MUST
NOT
contain
non-audio
resources.
An
audio
resource
can
MUST
be
referenced
in
its
entirety
via
a
URL
[
url
],
or
for
content
where
multiple
chapters
occupy
a
single
file
by
using
media
fragments
[
media-frags
]
to
locate
the
exact
starting
and
end
points.
].
Note
It
is
important
to
note
that
a
resource
cannot
be
referenced
more
than
once
in
the
reading
order.
In
the
case
where
an
audio
file
represents
the
content
of
multiple
chapters
or
sections
of
the
book,
the
table
of
contents
can
should
be
used
to
specify
the
starting
and
ending
points
of
those
chapters
in
the
larger
audio
file,
as
demonstrated
in
this
example
.
Proposed
Correction
1.1
Update
previously
non-normative
statement
about
the
use
of
media
fragments
to
allow
for
referencing
of
audio
files
that
span
multiple
chapters.
The
previous
statement
contradicted
the
note
on
referencing
an
audio
file
more
than
once
in
the
reading
order.
The
new
normative
statement
will
require
that
media
fragments
not
be
used
on
the
url
property
in
the
Reading
Order.
Note
Annotations
can
also
use
media
fragments
to
identify
the
location
of
the
annotation
in
the
resource,
and
are
compatible
with
the
Web
Annotations
model.
This
method
will
only
apply
to
audiobook
manifests
that
are
not
packaged.
Example
8
:
Audiobook
Reading
Order
for
a
Single
Resource
Example
9
:
Audiobook
Reading
Order
for
Multiple
Resources
using
Media
Fragments
{
],
,
,
,
: [{
,
,
,
,
}, {
,
,
,
,
}]
}
5.8
Resource
List
The
resource
list
enumerates
any
additional
resources
used
in
the
processing
and
rendering
of
an
audiobook
that
are
not
listed
in
the
reading
order.
It
is
expressed
using
the
resources
property.
If
an
audiobook
includes
supplemental
content
it
MUST
be
referenced
in
the
resource
list.
The
history
of
the
audiobook
is
rooted
in
the
world
of
accessibility.
Both
purely
audio
publications
and
publications
that
synchronize
text
and
audio
playback
have
long
been
used
to
assist
users
with
alternative
reading
needs
and
preferences.
An
approach
for
accessible
synchronized
media
in
publications
is
currently
being
done
by
the
Synchronized
Multimedia
for
Publications
Community
Group
.
Refer
to
the
work
of
that
group
for
more
information
about
creating
such
content
and
incorporating
it
into
an
Audiobook.
Alternatively,
a
content
creator
can
provide
the
text
equivalent
as
HTML
[
html
]
resources
in
the
resources
.
otherwise,
if
resource["duration"]
,
add
resource["duration"]
to
resourceDuration
.
If
the
values
cannot
be
compared
because
data["duration"]
is
not
set,
validation
error
.
Otherwise,
if
resourceDuration
does
not
specify
the
same
total
duration
as
data["duration"]
,
validation
error
.
Explanation
This
step
checks
both
that
all
resources
in
the
reading
order
specify
a
duration
and
that
the
sum
of
all
those
durations
matches
the
total
duration
for
the
publication.
A
validation
error
is
only
emitted
while
checking
each
resource
if
the
resource
does
not
specify
a
duration.
The
validity
of
the
durations
[
pub-manifest
]
is
already
checked
in
the
publication
manifest
algorithm
so
does
not
need
to
be
repeated.
This
step
checks
the
reading
order
and
resource
list
to
verify
that
a
cover
has
been
specified
(i.e.,
an
resource
has
the
value
cover
in
its
rel
property).
7.
User
Agent
Processing
of
Machine-Processable
Table
of
Contents
This
section
is
non-normative.
This
specification
extends
the
Publication
Manifest’s
User
Agent
Processing
Algorithm
for
Machine-Processable
Table
of
Contents
[
pub-manifest
]
to
locate
a
table
of
content
element
as
follows:
If
the
primary
entry
page
is
available,
then
execute
the
algorithm
locating
the
table
of
content
element
on
the
primary
entry
page.
If
the
previous
step
is
not
successful,
locate
the
relevant
resource,
if
available,
in
the
manifest
as
described
in
§ 4.8.1.3 Table
of
Contents
in
[
pub-manifest
],
and
execute
the
same
algorithm
on
that
resource.
As
Audiobooks
is
a
profile
of
Publication
Manifest
[
pub-manifest
],
all
security
and
privacy
considerations
detailed
in
that
specification
are
applicable
to
this
profile.
This
profile
acknowledges
the
following
considerations:
This
section
outlines
the
expected
user
agent
behaviors
for
implementation
of
audiobooks.
For
processing
instructions,
user
agents
should
refer
to
the
Processing
a
Manifest
section
of
the
Publication
Manifest
[
pub-manifest
]
specification,
and
conform
to
any
behavior
described
there.
All
user
agent
behaviors
described
in
this
section
are
intended
to
provide
implementors
with
guidance,
not
strict
requirements.
Behaviors
in
this
document
are
taken
mainly
from
the
Use
Cases
and
Requirements
[
pwp-ucr
]
note
published
by
the
working
group.
9.1
Opening
and
Navigating
the
Contents
of
an
Audiobook
When
a
user
agent
opens
an
Audiobook,
and
the
manifest
processes
according
to
the
rules
laid
out
in
Publication
Manifest
[
pub-manifest
],
it
should
be
opened
by
the
User
Agent.
The
Reading
Order
or,
if
available,
Table
of
Contents
should
be
accessible
to
the
user.
A
User
Agent
should
be
able
to
provide
a
list
of
the
contents
of
the
audiobook
available
to
the
user
when
requested.
If
a
non-audio
resource
is
present
in
the
Reading
Order,
the
User
Agent
can
choose
to
present
it
to
the
user
or
skip
it.
User
agents
should
provide
a
means
of
rendering
non-audio
resources
within
the
Reading
Order
and
Resource
list.
If
the
content
cannot
be
rendered
by
the
user
agent,
it
is
recommended
that
the
user
agent
inform
the
user
that
the
content
is
present
but
cannot
be
rendered.
The
Primary
Entry
Page
is
intended
to
be,
when
available,
the
entry
point
to
the
audiobook.
If
a
content
creator
has
provided
a
primary
entry
page,
and
the
User
Agent
is
capable
of
rendering
or
processing
HTML
content,
it
should
be
the
first
thing
presented
to
the
user.
The
Primary
Entry
Page
may
or
may
not
contain
a
Table
of
Contents,
if
included
using
the
role="doc-toc"
it
should
be
treated
as
the
Table
of
Contents.
If
the
Table
of
Contents
is
a
separate
document,
it
can
be
rendered
however
the
User
Agent
chooses
as
long
as
it
meets
the
requirements
laid
out
above.
If
no
Table
of
Contents
is
included
in
the
Primary
Entry
Page
or
elsewhere,
the
User
Agent
should
refer
to
the
Reading
Order.
9.2
Audiobook
Playability
As
outlined
in
the
Use
Cases
and
Requirements
[
pwp-ucr
]
note,
an
audiobook
must
be
navigable
in
the
User
Agent.
This
means
that
a
User
Agent
must
provide
methods
for
the
user
to
move
through
the
audiobook
in
a
linear
or
non-linear
fashion
by
either
moving
through
the
Reading
Order
seamlessly
or
by
accessing
the
Table
of
Contents
.
The
User
Agent
should
also
allow
the
user
to
move
through
individual
audio
files
in
short
time
increments.
For
an
audiobook,
the
User
Agent
should
provide
a
player
interface
[
pwp-ucr
]
that
will
allow
the
user
to
navigate,
play,
or
pause
the
audiobook.
This
interface
can
be
represented
to
the
user
in
any
way
(i.e.
physical
buttons,
visual
interface,
keyboard
input,
or
voice
commands),
but
should
be
accessible
at
any
point
in
the
listening
experience.
9.3
Audiobook
Packaging
and
Offlining
The
Use
Cases
and
Requirements
[
pwp-ucr
]
note
recommends
that
content
be
available
offline
and
that
any
packaged
formats
should
not
affect
the
iterations
of
the
publications.
This
means
that
even
if
the
content
is
copied
many
times
to
many
users
via
multiple
User
Agents,
the
core
manifest
and
its
identifier
are
never
changed.
This
specification
recommends
the
Lightweight
Packaging
Format
[
lpf
]
for
packaging
audiobook
content,
but
this
is
not
a
requirement.
Audiobook
User
Agents
should
be
able
to
ingest
LPF
files
for
play,
and
should
display
content
according
to
the
requirements
and
recommendations
in
this
document.
If
a
User
Agent
is
serving
the
content
directly
from
their
service
(i.e.
as
a
retailer
or
repository
of
content),
it
is
recommended
that
they
provide
a
method
for
offlining
or
downloading
the
content
to
the
user.
This
can
be
in
any
format
they
choose,
but
the
audiobook
should
be
complete
and
valid
and
the
contents
listed
in
the
manifest
should
be
served
in
their
entirety.
Even
if
a
User
Agent
does
not
support
the
display
of
a
certain
resource
(i.e.
an
image
file
or
data
table),
it
should
still
be
available
to
the
user
for
download.
This
specification
does
not
provide
a
method
for
content
creators
to
protect
or
watermark
their
content,
as
there
are
existing
methods
available
in
the
market
today.
User
Agents
who
work
with
content
creators
that
wish
to
protect
or
limit
the
distribution
of
their
content
can
choose
a
method
that
works
best
for
their
requirements.
9.4
Audiobooks
Accessibility
This
specification
recommends
and
provides
a
method
for
content
creators
to
create
fully
accessible
audiobooks
.
User
Agents
should
use
this
information,
in
the
section
on
Accessibility,
to
implement
accessible
audiobook
interfaces.
It
is
recommended
that
User
Agents
provide
accessible
player
interfaces,
as
well
as
a
method
for
content
creators
who
have
provided
alternate
content
to
have
that
content
displayed.
14-Sept-2020:
Added
a
note
that
informative
information
about
the
table
of
contents
structure
and
formatting
information
is
available
in
the
Publication
Manifest
specification.
See
issue
97
.
12-Sept-2020:
Removed
the
manifest
processing
step
that
warns
if
a
table
of
contents
is
not
found
as
the
requirement
is
dependent
on
the
presence
of
supplementary
resources
which
cannot
be
reliably
tested.
See
issue
93
.
8-Sept-2020:
Clarified
that
the
primary
entry
page
is
only
required
when
the
packaging
does
not
provide
an
alternative
method.
See
issue
61
.
26-Aug-2020:
Removed
the
example
of
synchronized
narration
and
updated
reference
to
the
work
of
the
Synchronized
Multimedia
for
Publications
Community
Group
to
reflect
the
early
nature
of
that
work.
See
issue
87
.
2-July-2020:
Added
a
note
about
the
shape
of
the
manifest
being
defined
by
the
JSON
schema
to
the
manifest
introduction.
See
issue
71
.
12-Feb-2020:
The
algorithm
step
to
check
and
compare
resource
durations
to
the
total
audiobook
duration
was
moved
to
avoid
duplicate
validity
checks.
The
algorithm
step
to
warn
about
the
primary
entry
page
not
being
listed
in
the
unique
resources
has
been
removed
as
it
is
no
checked
in
the
publication
manifest
algorithm.
See
issue
71
.
12-Feb-2020:
The
use
of
fragments
in
the
reading
order
was
clarified
to
also
include
end
position.
A
number
of
examples
were
also
fixed.
See
pull
request
69
.
07-Feb-2020:
The
manifest
requirements
section
was
moved
out
of
the
properties
section
as
it
also
includes
resource
relations.
See
issue
70
.
<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><title>Error</title></head><body><pre>Cannot GET /uploads/G4IJrD/tmp/experiments/flatland.json</pre></body>
</
html
>
A.2
Audiobook
with
Supplemental
Content
A
manifest
for
an
audiobook
with
supplemental
content.
<head>
&
<scripttype="application/ld+json">
{
"@context" : ["https://schema.org","https://www.w3.org/ns/pub-context"],
"conformsTo" : "https://www.w3.org/TR/audiobooks/",
&
"url" : "https://publisher.example.org/janeeyre",
&
}
</script>
&
</head><body>
&
<navrole="doc-toc"><ol><li><ahref="audio/chapter001.wav">Chapter 1. There was no possibility of taking a walk that day...</a></li><li><ahref="audio/chapter002.wav">Chapter 2. I resisted all the way:...</a></li><li><ahref="audio/chapter003.wav">Chapter 3. The next thing I remember is,...</a></li>
&
</ol></nav>
&
</
body
>
<navrole="doc-toc"><h2>JANE EYRE</h2><ol><li><ahref="audio/chapter001.mp3">Chapter 1. There was no possibility of taking a walk that day...</a></li><li><ahref="audio/chapter002.mp3">Chapter 2. I resisted all the way:...</a></li><li><ahref="audio/chapter003.mp3">Chapter 3. The next thing I remember is,...</a></li>
&
</ol>
</
nav
>
B.3
Table
of
Contents
with
Media
Fragments
A
table
of
contents
using
media
fragment
references
to
locations
in
a
single
audio
track.