Copyright
2023,
AOM
Licensing
information
is
available
at
http://aomedia.org/license/
The
MATERIALS
ARE
PROVIDED
“AS
IS.”
The
Alliance
for
Open
Media,
its
members,and
its
contributors
expressly
disclaim
any
warranties
(express,
implied,
or
otherwise),
including
implied
warranties
of
merchantability,
non-infringement,
fitness
for
a
particular
purpose,
or
title,
related
to
the
materials.
The
entire
risk
as
to
implementing
or
otherwise
using
the
materials
is
assumed
by
the
implementer
and
user.
IN
NO
EVENT
WILL
THE
ALLIANCE
FOR
OPEN
MEDIA,
ITS
MEMBERS,
OR
CONTRIBUTORS
BE
LIABLE
TO
ANY
OTHER
PARTY
FOR
LOST
PROFITS
OR
ANY
FORM
OF
INDIRECT,
SPECIAL,
INCIDENTAL,
OR
CONSEQUENTIAL
DAMAGES
OF
ANY
CHARACTER
FROM
ANY
CAUSES
OF
ACTION
OF
ANY
KIND
WITH
RESPECT
TO
THIS
DELIVERABLE
OR
ITS
GOVERNING
AGREEMENT,
WHETHER
BASED
ON
BREACH
OF
CONTRACT,
TORT
(INCLUDING
NEGLIGENCE),
OR
OTHERWISE,
AND
WHETHER
OR
NOT
THE
OTHER
MEMBER
HAS
BEEN
ADVISED
OF
THE
POSSIBILITY
OF
SUCH
DAMAGE.
1.
Introduction
This
document
specifies
how
to
carry
AV1
video
elementary
streams
([
AV1
])
in
the
MPEG-2
Transport
Stream
format
([
MPEG-2
TS
]).
It
does
not
specify
the
presentation
of
AV1
streams
in
the
context
of
a
program
stream.
This
document
defines
the
carriage
of
AV1
in
a
single
PID,
assuming
buffer
model
info
from
the
first
operating
point.
It
may
not
be
optimal
for
layered
streams
or
streams
with
multiple
operating
points.
Future
versions
may
incorporate
this
capability.
1.1
Modal
verbs
terminology
In
the
present
document
"shall",
"shall
not",
"should",
"should
not",
"may",
"need
not",
"will",
"will
not",
"can"
and
"cannot"
are
to
be
interpreted
as
described
in
clause
3.2
of
the
ETSI
Drafting
Rules
(Verbal
forms
for
the
expression
of
provisions).
1.2
Definition
of
mnemonics
and
syntax
function
In
the
present
document
the
mnemonics,
the
syntax
functions,
and
the
syntax
descriptors
are
to
be
interpreted
as
described
in
[
MPEG-2
TS
].
The
uimsbf
and
bslbf
mnemonics
are
defined
in
Section
2.2.6
of
[
MPEG-2
TS
].
The
nextbits()
function
is
interpreted
as
in
[
MPEG-2
TS
].
2.
Identifying
AV1
streams
in
MPEG-2
TS
2.1
AV1
registration
descriptor
The
presence
of
a
Registration
Descriptor,
as
defined
in
[
MPEG-2
TS
],
is
mandatory
with
the
format_identifier
field
set
to
'AV01'
(A-V-0-1).
The
Registration
Descriptor
shall
be
the
first
conveyed
in
the
PMT
descriptor
loop
for
the
respective
elementary
stream
entry
in
the
program
map
table,
and
included
before
the
AV1
video
descriptor.
2.1.1
Syntax
Syntax
No.
Of
bits
Mnemonic
registration_descriptor()
{
descriptor_tag
8
uimsbf
descriptor_length
8
uimsbf
format_identifier
32
uimsbf
}
2.1.2
Semantics
descriptor_tag
-
This
value
shall
be
set
to
0x05.
descriptor_length
-
This
value
shall
be
set
to
4.
format_identifier
-
This
value
shall
be
set
to
'AV01'
(A-V-0-1).
2.2
AV1
video
descriptor
The
AV1
video
descriptor
provides
basic
information
for
identifying
coding
parameters,
such
as
profile
and
level
parameters
of
an
AV1
video
stream.
The
same
data
structure
as
AV1CodecConfigurationRecord
in
ISOBMFF
is
used
to
aid
conversion
between
the
two
formats,
EXCEPT
that
two
of
the
reserved
bits
are
used
for
HDR/WCG
identification.
The
syntax
and
semantics
for
this
descriptor
appears
in
the
table
below
and
in
the
subsequent
text.
If
an
AV1
video
descriptor
is
associated
with
an
AV1
video
stream,
then
this
descriptor
shall
be
conveyed
in
the
descriptor
loop
for
the
respective
elementary
stream
entry
in
the
program
map
table.
2.2.1
Syntax
Syntax
No.
Of
bits
Mnemonic
AV1_video_descriptor()
{
descriptor_tag
8
uimsbf
descriptor_length
8
uimsbf
marker
1
bslbf
version
7
uimsbf
seq_profile
3
uimsbf
seq_level_idx_0
5
uimsbf
seq_tier_0
1
bslbf
high_bitdepth
1
bslbf
twelve_bit
1
bslbf
monochrome
1
bslbf
chroma_subsampling_x
1
bslbf
chroma_subsampling_y
1
bslbf
chroma_sample_position
2
uimsbf
hdr_wcg_idc
2
uimsbf
reserved_zeros
1
bslbf
initial_presentation_delay_present
1
bslbf
if
(initial_presentation_delay_present)
{
initial_presentation_delay_minus_one
4
uimsbf
}
else
{
reserved_zeros
4
uimsbf
}
}
2.2.2
Semantics
descriptor_tag
-
This
value
shall
be
set
to
0x80.
descriptor_length
-
This
value
shall
be
set
to
4.
marker
-
This
value
shall
be
set
to
1.
version
-
This
field
indicates
the
version
of
the
AV1_video_descriptor.
This
value
shall
be
set
to
1.
seq_profile
,
seq_level_idx_0
and
high_bitdepth
-
These
fields
shall
be
coded
according
to
the
semantics
defined
in
[
AV1
].
If
these
fields
are
not
coded
in
the
Sequence
Header
OBU
in
the
AV1
video
stream,
the
inferred
values
are
coded
in
the
descriptor.
seq_tier_0
,
twelve_bit
,
monochrome
,
chroma_subsampling_x
,
chroma_subsampling_y
,
chroma_sample_position
-
These
fields
shall
be
coded
according
to
the
same
semantics
when
they
are
present.
If
they
are
not
present,
they
will
be
coded
using
the
value
inferred
by
the
semantics.
hdr_wcg_idc
-
The
value
of
this
syntax
element
indicates
the
presence
or
absence
of
high
dynamic
range
(HDR)
and/or
wide
color
gamut
(WCG)
video
components
in
the
associated
PID
according
to
the
table
below.
HDR
is
defined
to
be
video
that
has
high
dynamic
range
if
the
video
stream
EOTF
is
higher
than
the
reference
EOTF
defined
in
[
BT-1886
].
WCG
is
defined
to
be
video
that
is
coded
using
colour
primaries
with
a
colour
gamut
not
contained
within
[
BT-709
].
hdr_wcg_idc
Description
0
SDR,
i.e.,
video
is
based
on
the
reference
EOTF
defined
in
[
BT-1886
]
with
a
color
gamut
that
is
contained
within
[
BT-709
]
with
a
[
BT-709
]
container
1
WCG
only,
i.e.,
video
color
gamut
in
a
[
BT-2020
]
container
that
exceeds
[
BT-709
]
2
Both
HDR
and
WCG
are
to
be
indicated
in
the
stream
3
No
indication
made
regarding
HDR/WCG
or
SDR
characteristics
of
the
stream
reserved_zeros
-
Will
be
set
to
zeroes.
initial_presentation_delay_present
-
Indicates
initial_presentation_delay_minus_one
field
is
present.
initial_presentation_delay_minus_one
-
Ignored
for
[
MPEG-2
TS
]
use,
included
only
to
aid
conversion
to/from
ISOBMFF.
3.
Constraints
on
AV1
streams
in
MPEG-2
TS
3.1
General
constraints
For
AV1
video
streams,
the
following
constraints
apply:
An
AV1
video
stream
conforming
to
a
profile
defined
in
Annex
A
of
[
AV1
]
shall
be
an
element
of
an
MPEG-2
program
and
the
stream_type
for
this
elementary
stream
shall
be
equal
to
0x06
(MPEG-2
PES
packets
containing
private
data).
An
AV1
video
stream
shall
have
the
low
overhead
byte
stream
format
as
defined
in
[
AV1
].
The
sequence_header_obu
as
specified
in
[
AV1
],
that
are
necessary
for
decoding
an
AV1
video
stream
shall
be
present
within
the
elementary
stream
carrying
that
AV1
video
stream.
An
OBU
may
contain
the
obu_size
field.
For
applications
that
need
easy
conversion
to
MP4,
using
the
obu_size
field
is
recommended.
OBU
trailing
bits
should
be
limited
to
byte
alignment
and
should
not
be
used
for
padding.
Tile
List
OBUs
shall
not
be
used
Temporal
Delimiters
may
be
removed
Redundant
Frame
Headers
and
Padding
OBUs
may
be
used.
In
addition,
a
start
code
insertion
and
emulation
prevention
process
shall
be
performed
on
the
AV1
Bitstream
prior
to
its
PES
encapsulation.
This
process
is
described
in
section
3.2.
3.2
Start-code
based
format
Prior
to
carriage
into
PES,
the
AV1
open_bitstream_unit()
is
encapsulated
into
ts_open_bitstream_unit()
.
This
is
required
to
provide
direct
access
to
OBU
through
a
start-code
mechanism
inserted
prior
to
each
OBU.
The
following
syntax
describes
how
to
retrieve
the
open_bitstream_unit()
from
the
ts_open_bitstream_unit()
(tsOBU).
emulation_prevention_three_byte
/*
equal
to
0x03
*/
8
uimsbf
}
else
open_bitstream_unit[NumBytesInObu++]
8
uimsbf
}
obu_start_code
-
This
value
shall
be
set
to
0x000001.
open_bitstream_unit[i]
-
i-th
byte
of
the
AV1
open
bitstream
unit
(As
defined
in
section
5.3
of
[
AV1
]).
It
is
the
responsability
of
the
TS
muxer
to
prevent
start
code
emulation
by
escaping
all
the
forbidden
three-byte
sequences
using
the
emulation_prevention_three_byte
(always
equal
to
0x03).
The
forbidden
sequences
are
defined
below.
Within
the
ts_open_bitstream_unit()
payload,
the
following
three-byte
sequences
shall
not
occur
at
any
byte-aligned
position
:
0x000000
0x000001
0x000002
Within
the
ts_open_bitstream_unit()
payload,
any
four-byte
sequence
that
starts
with
0x000003
other
than
the
following
sequences
shall
not
occur
at
any
byte-aligned
position
:
0x00000300
0x00000301
0x00000302
0x00000303
3.3
The
AV1
Access
Unit
An
AV1
Access
Unit
consists
of
all
OBUs,
including
headers,
between
the
end
of
the
last
OBU
associated
with
the
previous
frame,
and
the
end
of
the
last
OBU
associated
with
the
current
frame.
With
this
definition,
an
Access
Unit
sometimes
maps
with
a
Decodable
Frame
Group
(DFG)
as
defined
in
Annex
E
of
[
AV1
]
and
some
other
times
to
a
Temporal
Unit
(TU)
as
defined
in
[
AV1
],
or
both,
as
illustrated
in
the
figure
below.
An
illustration
is
provided
in
the
figure
below
for
a
group
of
pictures
with
frames
predicted
as
follows
:
Figure
1
Practical
example
of
an
AV1
Access
Unit
split
3.4
Use
of
PES
packets
AV1
video
encapsulated
as
defined
in
clause
4.2
is
carried
in
PES
packets
as
PES_packet_data_bytes,
using
the
stream_id
0xBD
(private_stream_id_1).
A
PES
shall
encapsulate
one,
and
only
one,
AV1
access
unit
as
defined
in
clause
4.3.
All
the
PES
shall
have
data_alignment_indicator
set
to
1.
Usage
of
data_stream_alignment_descriptor
is
not
specified
and
the
only
allowed
alignment_type
is
1
(Access
unit
level).
The
highest
level
that
may
occur
in
an
AV1
video
stream,
as
well
as
a
profile
and
tier
that
the
entire
stream
conforms
to,
shall
be
signalled
using
the
AV1
video
descriptor.
3.5
Assignment
of
DTS
and
PTS
For
AV1
video
stream
multiplexed
into
[
MPEG-2
TS
],
the
decoder_model_info
may
not
be
present.
If
the
decoder_model_info
is
present,
then
the
STD
model
shall
match
with
the
decoder
model
defined
in
Annex
E
of
[
AV1
].
For
synchronization
and
STD
management,
PTSs
and,
when
appropriate,
DTSs
are
encoded
in
the
header
of
the
PES
packet
that
carries
the
AV1
video
stream
data
setting
the
PTS_DTS_flags
to
'01'
or
'11'.
For
PTS
and
DTS
encoding,
the
constraints
and
semantics
apply
as
defined
in
the
PES
Header
and
associated
constraints
on
timestamp
intervals.
There
are
cases
in
AV1
bitstreams
where
information
about
a
frame
is
sent
multiple
times.
For
example,
first
to
be
decoded,
and
subsequently
to
be
displayed.
In
the
case
of
a
frame
being
decoded
but
not
displayed,
it
is
desired
to
assign
a
valid
DTS
but
without
need
for
a
PTS.
However,
the
MPEG2-TS
specification
prevents
a
DTS
from
being
transmitted
without
a
PTS.
Hence,
a
PTS
is
always
assigned
for
AV1
access
units
and
its
value
is
not
relevant
for
frames
being
decoded
but
not
displayed.
To
achieve
consistency
between
the
STD
model
and
the
buffer
model
defined
in
Annex
E
of
[
AV1
],
the
following
PTS
and
DTS
assignment
rules
shall
be
applied
:
show_existing_frame
show_frame
showable_frame
PTS
DTS
0
0
0
ScheduledRemovalTiming[dfg]
ScheduledRemovalTiming[dfg]
0
0
1
ScheduledRemovalTiming[dfg]
ScheduledRemovalTiming[dfg]
0
1
n/a
PresentationTime[frame]
ScheduledRemovalTiming[dfg]
1
n/a
n/a
PresentationTime[frame]
ScheduledRemovalTiming[dfg]
Note
:
The
ScheduleRemovalTiming[]
and
PresentationTime[]
are
defined
in
the
Annex
E
of
[
AV1
].
3.6
Buffer
considerations
3.6.1
Buffer
pool
management
Carriage
of
an
AV1
video
stream
over
[
MPEG-2
TS
]
does
not
impact
the
size
of
the
Buffer
Pool.
For
decoding
of
an
AV1
video
stream
in
the
STD,
the
size
of
the
Buffer
Pool
is
as
defined
in
[
AV1
].
The
Buffer
Pool
shall
be
managed
as
specified
in
Annex
E
of
[
AV1
].
A
decoded
AV1
access
unit
enters
the
Buffer
Pool
instantaneously
upon
decoding
the
AV1
access
unit,
hence
at
the
Scheduled
Removal
Timing
of
the
AV1
access
unit.
A
decoded
AV1
access
unit
is
presented
at
the
Presentation
Time.
If
the
AV1
video
stream
provides
insufficient
information
to
determine
the
Scheduled
Removal
Timing
and
the
Presentation
Time
of
AV1
access
units,
then
these
time
instants
shall
be
determined
in
the
STD
model
from
PTS
and
DTS
timestamps
as
follows:
The
Scheduled
Removal
Timing
of
AV1
access
unit
n
is
the
instant
in
time
indicated
by
DTS(n)
where
DTS(n)
is
the
DTS
value
of
AV1
access
unit
n.
The
Presentation
Time
of
AV1
access
unit
n
is
the
instant
in
time
indicated
by
PTS(n)
where
PTS(n)
is
the
PTS
value
of
AV1
access
unit
n.
3.6.2
T-STD
Extensions
for
AV1
When
there
is
an
AV1
video
stream
in
an
[
MPEG-2
TS
]
program,
the
T-STD
model
as
described
in
the
section
"Transport
stream
system
target
decoder"
is
extended
as
specified
below.
Figure
2
T-STD
Extensions
for
AV1
3.6.2.1
TB
n
,
MB
n
,
EB
n
buffer
management
The
following
additional
notations
are
used
to
describe
the
T-STD
extensions
and
are
illustrated
in
the
figure
above.
Notation
Definition
t(i)
indicates
the
time
in
seconds
at
which
the
i-th
byte
of
the
transport
stream
enters
the
system
target
decoder
TB
n
is
the
transport
buffer
for
elementary
stream
n
TBS
is
the
size
of
the
transport
buffer
TBn,
measured
in
bytes
MB
n
is
the
multiplexing
buffer
for
elementary
stream
n
MBS
n
is
the
size
of
the
multiplexing
buffer
MBn,
measured
in
bytes
EB
n
is
the
elementary
stream
buffer
for
the
AV1
video
stream
EBS
n
is
the
size
of
the
multiplexing
buffer
MBn,
measured
in
bytes
j
is
an
index
to
the
AV1
access
unit
of
the
AV1
video
stream
A
n
(j)
is
the
j-th
access
unit
of
the
AV1
video
bitstream
td
n
(j)
is
the
decoding
time
of
An(j),
measured
in
seconds,
in
the
system
target
decoder
Rx
n
is
the
transfer
rate
from
the
transport
buffer
TBn
to
the
multiplex
buffer
MBn
as
specified
below.
Rbx
n
is
the
transfer
rate
from
the
multiplex
buffer
MBn
to
the
elementary
stream
buffer
EBn
as
specified
below
The
following
apply:
There
is
exactly
one
transport
buffer
TB
n
for
the
received
AV1
video
stream
where
the
size
TBS
is
fixed
to
512
bytes.
There
is
exactly
one
multiplexing
buffer
MB
n
for
the
AV1
video
stream,
where
the
size
MBS
n
of
the
multiplexing
buffer
MB
is
constrained
as
follows:
MBS
n
=
BS
mux
+
BS
oh
+
0.1
x
BufferSize
where
BS
oh
,
packet
overhead
buffering,
is
defined
as:
BS
oh
=
(1/750)
seconds
×
max{
1100
×
BitRate,
2
000
000
bit/s}
and
BS
mux
,
additional
mutliplex
buffering,
is
defined
as:
BS
mux
=
0.004
seconds
×max{
1100
×
BitRate,
2
000
000
bit/s}
BufferSize
and
BitRate
are
defined
in
Annex
E
of
the
[
AV1
]
There
is
exactly
one
elementary
stream
buffer
EB
n
for
all
the
elementary
streams
in
the
set
of
received
elementary
streams
associated
by
hierarchy
descriptors,
with
a
total
size
EBS
n
:
EBS
n
=
BufferSize
Transfer
from
TB
n
to
MB
n
is
applied
as
follows:
When
there
is
no
data
in
TB
n
then
Rx
n
is
equal
to
zero.
Otherwise:
Rx
n
=
1.1
x
BitRate
The
leak
method
shall
be
used
to
transfer
data
from
MB
n
to
EB
n
as
follows:
Rbx
n
=
1.1
×
BitRate
The
removal
of
start-code
and
emulation
prevention
as
defined
in
section
4.2
is
instantaneously
performed
between
MB
n
and
EB
n
.
If
there
is
PES
packet
payload
data
in
MB
n
,
and
buffer
EB
n
is
not
full,
the
PES
packet
payload
is
transferred
from
MB
n
to
EB
n
at
a
rate
equal
to
Rbx
n
.
If
EB
n
is
full,
data
are
not
removed
from
MB
n
.
When
a
byte
of
data
is
transferred
from
MB
n
to
EB
n
,
all
PES
packet
header
bytes
that
are
in
MB
n
and
precede
that
byte
are
instantaneously
removed
and
discarded.
When
there
is
no
PES
packet
payload
data
present
in
MB
n
,
no
data
is
removed
from
MB
n
.
All
data
that
enters
MB
n
leaves
it.
All
PES
packet
payload
data
bytes
enter
EB
n
instantaneously
upon
leaving
MB
n
.
3.6.2.2
STD
delay
The
STD
delay
of
any
AV1
video
through
the
system
target
decoders
buffers
TB
n
,
MB
n
,
and
EB
n
shall
be
constrained
by
td
n
(j)
–
t(i)
≤
10
seconds
for
all
j,
and
all
bytes
i
in
access
unit
A
n
(j).
3.6.2.3
Buffer
management
conditions
Transport
streams
shall
be
constructed
so
that
the
following
conditions
for
buffer
management
are
satisfied:
Each
TB
n
shall
not
overflow
and
shall
be
empty
at
least
once
every
second.
Each
MB
n
,
EB
n
and
Buffer
Pool
shall
not
overflow.
EB
n
shall
not
underflow,
except
when
the
Operating
parameters
info
syntax
has
low_delay_mode_flag
set
to
'1'.
Underflow
of
EB
n
occurs
for
AV1
access
unit
A
n
(j)
when
one
or
more
bytes
of
A
n
(j)
are
not
present
in
EB
n
at
the
decoding
time
td
n
(j).
4.
Acknowledgements
and
previous
authors
A
previous
draft
of
this
specification
has
been
produced
by
VideoLAN,
with
inputs
from
different
authors
(Jean
Baptiste
Kempf,
Kieran
Kunhya,
Adrien
Maglo,
Christophe
Massiot,
Mathieu
Monnier
and
Mickael
Raulet)
from
the
following
companies:
ATEME,
OpenHeadend,
Open
Broadcast
Systems,
Videolabs
under
the
direction
of
VideoLAN.
