BD-RE Part3 V2.1 White Paper - Blu

BD-RE Part3 V2.1 White Paper - Blu
White Paper
Blu-ray Disc™
Rewritable Format
Audio Visual Application Format
Specifications
for BD-RE Version 2.1
July 2010
White Paper Blu-ray Disc™ Rewritable Format
Conditions of Publication
COPYRIGHT
All rights reserved. This document contains information that is proprietary information of the Blu-ray
Disc Association and its members and may not be used, copied or distributed without the written
permission of the Blu-ray Disc Association or its License Office. All other use, copying and distribution
are prohibited.
TRADEMARK
Blu-ray Disc™, Blu-ray™ and the logos are trademarks of the Blu-ray Disc Association.
DISCLAIMER
The information contained herein is believed to be accurate as of the date of publication. However,
none of the Blu-ray Disc Association, its Members, or its License Office will be liable for any damages,
including indirect or consequential, from use of the White Paper or reliance on the accuracy of this
document.
LICENSING
License is required from the Blu-ray Disc Association for the application of the System Description Bluray Disc™ Format in both disc and equipment products.
NOTICE
For any further explanation of the contents of this document, or in case of any perceived inconsistency
or ambiguity of interpretation, please consult with:
Blu-ray Disc Association
License Office
10 Universal City Plaza, T-100,
Universal City, CA 91608 U.S.A.
Fax.:
Web Site:
E-mail:
+1-818-763-9027
http://www.blu-raydisc.info
license@bdamail.com
© Blu-ray Disc Association 2010. All rights reserved.
i
White Paper Blu-ray Disc™ Rewritable Format
Table of Contents
Table of Contents
1.
Overview .............................................................................................................1
2.
Recording of Digital Broadcasts ..........................................................................3
2.1.
Recording MPEG-2 transport stream of digital broadcast......................................................3
2.2.
Support of Advanced video codec (MPEG-4 AVC) ................................................................9
2.2.1.
AVC Transcode mode ....................................................................................................9
2.2.2.
HDMV compatible TS mode ...........................................................................................9
2.2.3.
Interoperability between BDAV and BDMV ................................................................. 10
3.
4.
Recording of Analog Broadcasts.......................................................................11
3.1.
Self-Encoded Stream Format (SESF) ................................................................................. 11
3.2.
Constrained Self-Encoded Stream Format (C-SESF)......................................................... 12
Direct Recording of DV Input.............................................................................13
4.1.
Overview.............................................................................................................................. 13
4.2.
DV Stream Recording Format ............................................................................................. 13
4.3.
Random Access Method ..................................................................................................... 15
4.4.
Minimum Extent Size........................................................................................................... 15
5.
User Interface....................................................................................................17
6.
Editing ...............................................................................................................23
ii
6.1.
Seamless Connection Editing.............................................................................................. 23
6.2.
Audio Dubbing ..................................................................................................................... 26
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Overview
1.
Overview
The BD-RE Part3 "Audio Visual Basic Specifications" Version 2.1 defines the data structure of the
file and the mechanism for stream management and user presentation.
BD-RE (Rewritable),
BD-R (Write once)
Application
Standard
BD-RE
BD-RE
Part-3
Part-3Ver.2.1
Ver.2.1
BD-RE
BD-RE
Part-3
Part-3Ver.3.0
Ver.3.0
BD-ROM
(Prerecorded)
BD-ROM
BD-ROM
Part-3
Part-3
File System
Standard
BD-RE/BD-R
BD-RE/BD-R
BD-ROM
BD-ROM
Physical
Standard
BD-RE/BD-R
BD-RE/BD-R
BD-ROM
BD-ROM
Part-2
Part-2
Part-1
Part-1
Part-2
Part-2
Part-1
Part-1
Figure 3.1.1.1: Structure of the BD Standard
Since the commencement of BS digital broadcasting and digital terrestrial broadcasting in Japan,
digital Hi-Vision programs can be enjoyed on several channels and spread to homes in Japan. The
BD-RE Part3 "Audio Visual Basic Specifications" Version 2.1 takes advantage of characteristic disc
features such as ease-of-use and ease-of-editing and enables BS digital and digital terrestrial
broadcasts to be recorded and stored while maintaining the original picture quality. Making full use of
the large capacity and high transfer rate of the BD-RE disc, the BD-RE Part3 Version 2.1 has been
designed to achieve the following:
• Recording of digital broadcasts including high-vision programmimg while maintaining the original
picture quality—up to 2 hours on a single-layer disc and 4 hours on a dual-layer disc
• Supporting Advanced Video Coding (AVC) for trans-coding of video (MPEG-2 HD video to AVC HD
video) and a long time recording mode of digital broadcasting
• Long time recording of analog broadcasts such as standard definition (SD) programs (With a picture
quality that is equivalent to that of VHS standard mode, approximately 12 hours can be recorded on
a single-layer disc or approximately 24 hours on a dual-layer disc.)
• Seamless, non-destructive editing which takes advantage of disc features
• Direct recording of DV contents from the DV terminal of the camcorder with no picture deterioration
(option)
• User interface that supports recorded content management in a visual manner
© Blu-ray Disc Association 2010. All rights reserved.
1
White Paper Blu-ray Disc™ Rewritable Format
Overview
Capacity and Recording time
Dual layer: 50GB
30
Single layer: 25GB
Multiplexing rate (Mbps)
DV: 28.8Mbps
25
BS digital HDTV: 24Mbps
20
15
SD(High quality): 15Mbps
10
SD(equivalent to VHS
SP mode): 4Mbps
5
0
0
10
20
30
40
50
Recording Time (Hour)
Figure 3.1.1.2: Relation between Capacity and Recording time
2
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
2.
Recording of Digital Broadcasts
2.1.
Recording MPEG-2 transport stream of digital broadcast
The main characteristic of the recording format under the BD-RE Application Format is its adoption
of MPEG-2 TS (Transport Stream) for stream multiplexing.
DVD Video, on the other hand, employs MPEG-2 PS (Program Stream) as its multiplexing format. In
comparison with MPEG-2 PS, MPEG-2 TS has a small packet size fixed at 188 bytes; it can multiplex
multiple channels and EPG (Electronic Program Guide) information and is altogether more suited to
broadcasting. The BD-RE Application Format enables transport streams of digital broadcasts to be
recorded as they are without altering the format.
In current BS digital broadcasting systems, a single transponder is occupied by two or four transport
streams and multiple programs (that is channels) are multiplexed in a single transport stream. A
transport stream like this that is used for broadcasting and contains multiple programs is called a full
transport stream (Fig. 3.1.2.1). On the other hand, a partial transport stream is made from the full
transport stream by extracting the video/audio/data components of a particular program and
reconfiguring the PSI/SI (Program Specific Information/Service Information), information which
describes the programs.
(A) ES (Elementary stream) outputed from Encoder
Video ES V1
Audio ES A1
(B) PES (Packetized elementary stream)
PES packet header
Channel 1
PES packet
Video PES V1
Audio PES A1
Channel 2
Video PES V2
Audio PES A2
PAT
TS packet
188bytes
PMT
V1
V2
A1
V2
V1
V1
A2
TS packet header
(C) Example of MPEG-2 TS into which Channel 1 and Channel 2 are multiplexed
Figure 3.1.2.1: MPEG-2 Transport Stream that multiple channels are multiplexed
If a digital broadcast recorder were to record a full transport stream in its original form, the
video/audio/data components of unwanted channels would also be recorded and use up the recording
© Blu-ray Disc Association 2010. All rights reserved.
3
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
area. The conversion from full to partial transport stream is an important process for the recorder, as
this process lowers the recording rate and allows the recording area to be used efficiently (Fig. 3.1.2.2).
MPEG-2 Full TS
MPEG-2 Partial TS
PSI/SI
PSI/SI
PAT
EIT
PAT
PMT
PMT
PMT
PMT
SIT
Full – Partial
Conversion
Program 1
Program 1
Video 1
Audio 1
Program 2
Video 2
Audio 2
Program 3
Video 3
Audio 3
Video 1
Audio 1
Figure 3.1.2.2: Conversion from Full TS to Partial TS
As shown in Fig. 3.1.2.3, in a partial transport stream which is reconstructed from the necessary
packets extracted from the full transport stream, the time intervals between packets are not always the
same. These packet intervals are determined by the buffer model and they must be observed when
the packets are input to the demultiplexer/decoder or else the buffer will overflow or underflow and
data will not be decoded correctly. For this reason, a header is added to each TS packet during
recording to indicate the time that the TS packet arrived at the T-STD (Transport stream-System
Target Decoder). Under the BD-RE Application Format, a TS packet attached with its packet arrival
time is called a source packet. During playback, the packet intervals before recording are reproduced
accurately based on the packet arrival times recorded in the source packet headers and the packets
are then output to the T-STD or to outside the device (Fig. 3.1.2.4 and Fig. 3.1.2.5).
4
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
Input from BS digital tuner
Inputted Full TS1
TS packets lined up contiguously with fixed rate
Time
Full-Partial Conversion
Partial TS with one program
TS packets are discretely located in a line on a time-axis
Time
Buffer Memory
Wait
Recording
Adding
Time stamp
until enough data is
accumulated in the buffer.
PSI/SI
Recording
Intermittent
recording
TS packet for Program1
To maintain the input time of TS to
decoder system, time stamp is added
to every TS packet. These TS
packets are stored into Buffer
Memory and the packet interval is
narrowed and they are recorded
intermittently.
TS packet for Program2
Disc
TS packet for Program2
Time stamp indicating input timing of its
TS packet to decoder system
Figure 3.1.2.3: Data flow until the inputted Transport Stream is recorded to the disc
© Blu-ray Disc Association 2010. All rights reserved.
5
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
Input from
external digital
STB, or
Output of
internal encoder
Transport Stream
packet
(MPEG-2 TS)
27MHz
PLL
t(i)
Transport Stream
System Target
Decoder
27MHz
CLK
Display
device
Counter for
arrival time
clock
arrival_time_clock(i)
PCR
t(i)
Source
packetizer
RMAX
Source
packet
Write
Buffer
RUD
BD
Drive
t(i): time when i-th byte of the Transport stream is entered
arrival_time_clock(i): value of the Counter for arrival time clock at the time, t(i)
RMAX: transfer rate of Source packet from Source packetizer
RUD: data recording rate to BD drive
Figure 3.1.2.4: Recorder model for MPEG-2 TS
6
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
27MHz
CLK
27MHz
Clock
generator
Counter for
arrival time
clock
Load
initial counter value
BD
drive
R UD
Read
Buffer
R MAX
Source
packet
arrival_time_clock(i)
Source
de-packetizer
R TS
Transport Stream packet
(MPEG2 TS)
Output (to external device)
Transport Stream
System
Target Decoder
Display
device
arrival_time_clock(i ):
value of the Counter for arrival time clock at the time when
i-th byte
in the Transport Stream is outputted from Source de -packetizer
R : read data rate from BD drive
UD
R
: read rate of Source packet from Read Buffer
MAX
R : mux_rate of the Transport Stream
TS
Figure 3.1.2.5: Player model for MPEG-2 TS
When recording a transport stream to disc, the information of other programs and other unwanted
information are deleted from the PSI/SI and the information reconfigured and the recording is
processed in accordance with copy control information; however, no changes are necessary at the
coded data level (elementary stream) such as down-converting or re-encoding which affect picture and
sound quality. This is how the BD-RE Application Format enables recording of Hi-Vision video, which
can have a maximum bit rate of 24Mbps as shown in Fig. 3.1.2.6, and multi-channel audio while
keeping the original broadcast quality.
© Blu-ray Disc Association 2010. All rights reserved.
7
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
Video
Profile and
Effective
Level
number of
pixel number
scanning lines
Horizontal
aspect ratio
bitrate
MP@HL
1080i
1920,
1440
16:9
24Mbps max
MP@HL
720p
1280
16:9
24Mbps max
MP@H14L
480p
720
16:9
24Mbps max
MP@ML
480i
720, 544,
16:9 or 4:3
15Mbps max
480
Coding
MPEG-2 AAC LC profile
Channel
5.1channel max
bitrate
Stereo
144kbps max
HiFi stereo
(Compression mode B)
192kbps~256kbps
Multi-channel
384kbps max
Audio
fs
48kHz, (32kHz is possible for Digital Radio service)
Figure 3.1.2.6: Video/Audio format of Japanese BS Digital Broadcast
The BD-RE Application Format also supports the recording of BS digital data broadcasts written in
BML, a language that is based on XML. A data broadcast is made up of several files and consists of
video/audio elements and a program that controls these elements. The files are segmented into
sections, a format defined by MPEG-2 TS, and are transmitted repeatedly by the broadcast station in
predetermined cycles (data carousel transmission). The receiver obtains one cycle of data beginning
from a certain time and extracts the data in its internal memory to restore the files and execute the
program. Because the timing of data multiplexing at the time of broadcast is retained under the BD-RE
Application Format, the data broadcast is recorded in MPEG-2 TS format without being separated into
files.
A convenient feature of digital broadcasting is EPG. The EPG is reconstructed from the PSI/SI
multiplexed in the full transport stream: when recording to disc, the necessary information of recorded
program is extracted from the PSI/SI and program information is reconstructed in a table called SIT
and recorded. This makes it possible to view detailed program information even during playback.
The partial transport stream is also used as the multiplexing format for MPEG-2 streams that pass
through i.LINK. Transport streams that are input to the BD-RE recorder from an external digital
broadcast receiver via i.LINK can also be recorded without picture/audio deterioration.
In addition to digital broadcasting in Japan, there is DTV in America and DVB in Europe; partial
transport stream recording is a highly adaptable recording format which can also be applied to these
broadcasting systems.
8
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
2.2.
Support of Advanced video codec (MPEG-4 AVC)
BD-RE Part 3 version2.1 supports Advanced Video Coding (AVC) for trans-coding of video (MPEG-2
HD video to AVC HD video) and a long time recording mode of digital broadcasting.
BD-RE Part 3 version2.1 has the following two extensions:
- AVC Transcode mode
- HDMV compatible TS mode
2.2.1.
AVC Transcode mode
Video elementary stream from the digital broadcast TS is re-encoded to an MPEG-4 AVC video
stream, while the other elementary streams (audio streams etc) in the TS keep the original. The reencoded video stream and the other original streams are remultiplexed. MPEG-4 AVC streams of
HDMV compatible TS mode have the same constraint as RREF (Realtime recording and Editing
Format) (Note1) stated in BD-RE Part3 Version 3.0.
(Note1): The overview of RREF is stated in the “White Paper Blu-ray Disc Rewritable Format
Audio Visual Application Format Specifications for BD-RE Version 3.0”.
2.2.2.
HDMV compatible TS mode
TS and elementary streams of HDMV compatible TS mode have the same constraint as RREF
(Realtime recording and Editing Format) (Note1) stated in BD-RE Part3 Version 3.0. In HDMV
compatible TS mode, the video elementary stream is re-encoded to MPEG-4 AVC video stream and
the audio elementary stream is re-encoded to Dolby AC3 audio or Linear PCM audio.
Elementary streams of HDMV compatible mode
Name of
Coding method of
elementary stream
elementary stream
Video stream
MPEG-4 AVC video
Audio stream
Linear PCM audio
Dolby AC-3 audio
Graphics stream
Presentation graphics stream
© Blu-ray Disc Association 2010. All rights reserved.
9
White Paper Blu-ray Disc™ Rewritable Format
Recording of Digital Broadcasts
¾ AVC Transcode mode of Digital broadcast TS
An Example of
ARIB case
Transcode mode TS
ARIB digital broadcast TS
MPEG2 video HDTV
Dec
Enc
AVC video HDTV
AAC audio 5.1ch
AAC audio 5.1ch
Broadcast subtitle
Broadcast subtitle
¾ HDMV compatible TS mode
ARIB digital broadcast TS
HDMV compatible TS
MPEG2 video HDTV
Dec
Enc
AVC video HDTV
AAC audio 5.1ch
Dec
Enc
AC-3 audio
Broadcast subtitle
2.2.3.
Interoperability between BDAV and BDMV
The HDMV compatible TS mode can realize transforming the BDAV format (BD-RE Part3 Version 2.1)
to the BDMV format (BD-RE Part3 Version 3.0) easily. For transforming the HDMV compatible TS of
BDAV to the BDMV format, the HDMV compatible TS can be re-used as is, and the BDAV Clip
Information file and PlayList files are transformed to the BDMV Clip Information file and PlayList file
format.
BD-RE Part3 Version 2.1
BD-RE Part3 Version 3.0
BDAV
BDAV PlayList file
BDMV PlayList file
BDAV Clip Information file
Transform
BDMV Clip Information file
HDMV compatible TS
10
BDMV
Transform
HDMV TS
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Recording of Analog Broadcasts
3.
Recording of Analog Broadcasts
Although the BD-RE Application Format was designed for recording and playing back high-definition
(HD) digital broadcasts, the format is also capable of recording/playing analog SDTV broadcasts, by
using the HDMV compatible TS or SESF stated below.
3.1.
Self-Encoded Stream Format (SESF)
SESF makes it possible to record/play current analog broadcasts efficiently in addition to HD digital
broadcasts, and also guarantees compatibility between BD devices.
SESF conforms to the MPEG-2 TS systems standard (ISO/IEC 13818-1) and is limited to the
streams that are required for encoding NTSC (or PAL) video input signals. Thus, the video stream of
SESF can be decoded by standard MPEG decoders such as BS digital receivers.
As shown in Fig. 3.1.3.1.1, SESF recorded streams are defined as video, audio and teletext streams.
Video
Audio
Teletext
Tip data
MEPG-2 video
MPEG-1 audio
Dolby AC-3 audio
Linear PCM audio
supported for PAL
Tip TS
Figure 3.1.3.1.1: Elementary data of SESF
Video streams are encoded in MPEG-2 MP@ML format and recorded on a BD disc.
Video signals with the resolutions shown in Fig. 3.1.3.1.2 and Fig. 3.1.3.1.3 can be used and NTSC
and PAL video signals are guaranteed to be recorded at sufficient resolutions. NTSC signals can be
recorded at a maximum resolution of 720x480 pixels, which is equivalent to that of DVD packaged
media.
720 x 480
704 x 480
544 x 480
480 x 480
352 x 480
352 x 240
Figure 3.1.3.1.2: Resolution under 525/60
720 x 576
704 x 576
544 x 576
480 x 576
352 x 576
352 x 288
Figure 3.1.3.1.3: Resolution under 625/50
SESF provides three types of recording formats for audio streams ranging from a low bit rate to high
audio quality, as shown in Fig. 3.1.3.1.4.
© Blu-ray Disc Association 2010. All rights reserved.
11
White Paper Blu-ray Disc™ Rewritable Format
Recording of Analog Broadcasts
CODEC
MPEG-1 Layer 2
Dolby Digital
LPCM
fs
48 kHz
48 kHz
48 kHz
bits per sample
16, 20, 24 bits
channel
2 ch
5.1 ch max
2 ch
bitrate
32 kbps – 384 kbps
64 kbps – 448 kbps
1.536 Mbps – 2.304 Mbps
Figure 3.1.3.1.4: Audio CODEC for SESF
The first audio format is MPEG-1 Layer-2, which is widely used in general consumer equipment (e.g.
DTV STB) and is suited to recording at comparatively low bit rates. The Dolby Digital (AC-3) format is
the standard used in US satellite broadcasts and DVDs and allows relatively high-quality audio
recording. In addition to these two formats, SESF provides a linear PCM format (optional) that
supports 2-channel linear PCM recording of up to 48kHz, 24 bits for audio recording of even higher
quality than that of existing CD and DVD recorders.
3.2.
Constrained Self-Encoded Stream Format (C-SESF)
BD-RE Application Format also allows SESF recording which can be converted to MPEG-2 PS with
predetermined simple method and the stream format is called Constrained Self-Encoded Stream
Format (C-SESF).
The Constrained SESF handles 11 TS packets as a single unit called a multiplexing unit, shown in
Fig. 3.1.3.2.1. A multiplexing unit holds up to 2048 bytes of valid data and can be converted to a
program stream and recorded in a 2048-byte sector.
Figure 3.1.3.2.1: Stream of Constrained SESF
An SESF capsule is a grouping of video and audio data that consist of one or more GOPs (Group Of
Pictures) and has been designed to enable playback and editing in units of SESF capsules. A Tip
packet and PAT, PMT are inserted at the beginning of the SESF capsule.
The Tip packet contains display information such as the aspect ratio of the video data in the stream,
CGMS such as the copy control information, and coding information such as the video resolution, and
so on. All of this information makes it possible to quickly identify the decoding method before decoding
the data.
During skip or high-speed playback, video data can be easily decoded by starting playback from the
beginning of the SESF capsule.
12
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Direct Recording of DV Input
4.
Direct Recording of DV Input
4.1.
Overview
Taking advantage of the BD-RE drive’s high user transfer rate (36Mbps), the BD-RE Application
Format provides an optional functionality of recording DV streams (28.8Mbps) to BD-RE disc via the
i.LINK.
BD recorders that support this functionality enable users to record video material taken with a DV
camcorder on BD-RE disc and take advantage of non-linear editing and other functions characteristic
of disc media.
4.2.
DV Stream Recording Format
The recording format for the DV stream conforms to the DVCR digital interface standard (IEC
61883-2) (Fig. 3.1.4.2.1). The DV stream received through i.LINK is not re-encoded but recorded
directly to disc, with aligning the beginning of the DV stream with the logical sector boundary, as
shown in Fig. 3.1.4.2.2(a).
Data in one frame
DIF sequence
DIF seq. 0
Structure of
DIF sequence
Header
DIF Block
Structure of
DIF Block
DIF seq. 1
Subcode
DIF seq. n-1
VAUX
DIF Block 0 DIF Block 1 DIF Block 2
ID
3 bytes
120,000 bytes (525 / 60)
144,000 bytes (626 / 50)
n=10 (525 / 60)
n=12 (626 / 50)
Audio and Video
DIF Block 148 DIF Block 149
Data
77 bytes
DIF: Digital Interface
Figure 3.1.4.2.1: Data structure of DV stream
(compliant with digital interface standard for DVCR)
© Blu-ray Disc Association 2010. All rights reserved.
13
White Paper Blu-ray Disc™ Rewritable Format
Direct Recording of DV Input
Portion
to be deleted
(a) First recording
120,000 bytes (525 / 60)
144,000 bytes (626 / 50)
#N-1
#N
#N+1
DV stream file
Data allocation
on a disc
Frame No.
Frame No.
#0
DV stream
#N
#0
Sector boundary
Relative address
from the top of file
(unit in bytes)
Logical sector
(b) After delete-operation
DV stream
削除
フレーム
#N
#N+1
DV stream after delete-operation
Data allocation
on a disc
S
Figure 3.1.4.2.2: DV stream on Disc
Also, as well as MPEG-2 TS recording, a Clip information file in which DV stream property
information is stored is created for each stream file. Since the DV stream and MPEG-2 transport
stream have different structures, a Clip information file that provides basic information for random
access is defined for DV stream. In this way, differences in stream structure are absorbed by the Clip
information file so that the PlayList as a top-layer of DV and MPEG-2 TS uses the same data structure.
Fig. 3.1.4.2.3 shows the directory and file structures. DV stream files are stored in the
/BDAV/STREAM directory as are TS files. DV stream files have the extension “dvsd” and are
accordingly distinguished from TS files. Clip information files and PlayLists are stored in the same
directories as for TS files, BDAV/CLIPINF and /BDAV/PLAYLIST respectively.
14
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Direct Recording of DV Input
root
BDAV
info.bdav
PLAYLIST
01001.rpls
02002.rpls
99999.vpls
CLIPINF
01000.clpi
02000.clpi
Clip Information file
corresponding to the DV stream file,
02000.dvsd
03000.clpi
STREAM
01000.m2ts
02000.dvsd
DV stream file
03000.m2ts
Figure 3.1.4.2.3: Stream file and Clip Information file for DV in BDAV
directory
4.3.
Random Access Method
Since the video compression method adopted by the DV format is intraframe coding, each frame in
the DV stream has a fixed number of bytes (525/60:120,000byte, 625/50:144,000byte). Therefore, the
addresses of the frame data corresponding to the playback start and end times specified in the
PlayList can be obtained using a simple calculation.
As shown in Fig. 3.1.4.2.2(a), the frame numbers counted from the beginning of the file and their
relative addresses are proportional to each other and this relationship can be used to easily obtain the
relative address of a random access point.
This is why with the Clip information file for a DV stream there is no need to create a table (CPI) for
random access such as EP_map or TU_map (see 3.1.5), which are required for MPEG-2 TS recording.
With linear editing, there may be cases where part of the DV stream file is removed (for instance,
frames #0 to #N-1 in Fig. 3.1.4.2.2(a)). Because files are managed in logical sector units by the file
system, after part of the file is removed, the beginning of the first frame will be offset from the
beginning of new file, as indicated by the dark shade in Fig. 3.1.4.2.2(b). In this case, offset
information S and the new top frame number #N are recorded in the Clip information file so that there
is no need to shift stream data or add changes to the PlayList.
4.4.
Minimum Extent Size
In general, the minimum extent size for recording needs to be defined in order to achieve seamless
recording and playback. Because the DV stream has a comparatively high transfer rate of 28.8Mbps,
© Blu-ray Disc Association 2010. All rights reserved.
15
White Paper Blu-ray Disc™ Rewritable Format
Direct Recording of DV Input
the minimum extent size must be sufficiently large. The BD-RE Application Format provides for two
minimum extent sizes according to stream rate so that streams with a lower transfer rate than the DV
stream can be recorded in an efficient manner. Defining the minimum extent size in this way makes
seamless playback possible.
If part of a stream is removed, as described above, the stream may end up with sections that do not
meet the conditions for contiguous recording required for seamless playback. However, even in this
case, seamless playback can be achieved after part of the DV stream is removed by using the bridge
sequence described later.
16
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
User Interface
5.
User Interface
Fig. 3.1.5.1 shows a conceptual diagram of stream management under the BD-RE Application
Format. Stream management consists of two main layers, the PlayList layer and the Clip layer. The
PlayList is a unit that represents a grouping of video/audio data to the user. For instance, a sequence
of video/audio data from recording start to end constitutes a single PlayList and PlayList construction
information is recorded as a single PlayList file. Only the PlayList layer can be seen from the user.
Management structure for
Blu-ray Disc Rewritable Application
Real PlayList
Real PlayList
Virtual PlayList
PlayItem
PlayItem
PlayList layer
Time
Clip Layer
Time to
Byte address
conversion
Stream data
for seamless
connection
Clip Information file
Clip Information
file
Clip Information
file
Clip AV stream
Clip AV stream
Clip AV stream
Clip
Bridge Clip
Byte
Clip
Figure 3.1.5.1: Management structure of stream in BD-RE Application format
The layer below the PlayList layer is the Clip layer which manages AV stream files. The Clip layer
consists of AV stream files which store actual video/audio stream data and Clip information files that
correspond one to one with Clip AV streams.
The Clip information file is composed of database which contains the information of non-contiguous
STC points and program information regarding MPEG-2 TS, and stream’s characteristic point
information (CPI), and so on. The CPI is entry point information and is used to achieve high-speed
random access and variable-speed playback.
First, the BD-RE Application Format assumed streams to be variable bit-rate MPEG video and
defined an EP_map (Fig. 3.1.5.2) to store the byte positions in the file from which decoding can be
started, such as the beginning of a GOP. From this table, which defines the relationship between pts
and the source packet numbers representing byte positions in the file, the address within the file for a
specific time can be known immediately even for VBR (Variable Bit Rate) encoded streams. The BDRE Application Format also defined a TU_map (Fig. 3.1.5.3) for recording transport streams other than
MPEG video.
© Blu-ray Disc Association 2010. All rights reserved.
17
White Paper Blu-ray Disc™ Rewritable Format
User Interface
pts(x1)
pts(y1)
pts(z1)
pts(y2)
pts(x2)
pts(z2)
Clip
AV stream
pts(yn)
pts(zm)
pts(xk)
...
X2
X1
Y1
SPN
(Source packet No.)
Xk
Y2
Yn
Z1
Z2
Zm
Source packet which contains the first byte of the Sequence header
video_PID=x
Source packet which contains the first byte of the Sequence header
video_PID=y
Source packet which contains the first byte of the Sequence header
video_PID=z
EP_map
EP_map1
EP_map2
PID of the stream = x
Number of Entry points = k
PID of the stream = y
Number of Entry points = n
PID of the stream = z
Number of Entry points = m
pts of the SPN of the
Entry point Entry point
pts of the SPN of the
Entry point Entry point
pts of the SPN of the
Entry point Entry point
pts(x1)
pts(x2)
...
pts(xk)
X1
X2
...
Xk
pts(y1)
pts(y2)
...
pts(yn)
Y1
Y2
...
Yn
EP_map3
pts(z1)
pts(z2)
...
pts(zm)
Z1
Z2
...
Zm
Figure 3.1.5.2: Example of EP_map
This example shows that three Video elementary streams are contained in one TS
18
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
User Interface
TU_time_base
arrival_end_time
:
arrival_start_time
...
time_unit_size
Arrival
time clock
TU_map
Time of 1 time_unit
offset_arrival_time(Time at starting point)
offset_ arrival_time
=TU_start_time #0
TU_start_
time #1
time_unit #0
TU_start_
time #2
...
time_unit #1
input
transport
packets
SPN_time_unit_start #0
SPN_time_unit_start #1
SPN_time_unit_start #2
TU_start_
time #N
time_unit #N
transport
packet
SPN_time_unit_start #3
:
:
:
...
Arrival
time clock
ATC-sequence
...
source packet
SPN (Source packet number)
SPN_
time_unit
start #0
SPN_
SPN_
time_unit time_unit
start #1
start #N
Figure 3.1.5.3: Example of TU-map
In case a stream is recorded, the source packet number of which the packet
arrives first within a certain time interval defined as a time_unit is stored.
SPN_time_unit is the relative byte position in a file.
When the TU_map is used, time access is performed in units of time_unit and becomes less
precise; however, random access operation of arbitrary transport streams becomes possible. The
EP_map together with the TU_map are called CPI. These databases are created by the recorder
when it records the stream.
The PlayList is a sequence of play-items. A play-item is a set of IN, OUT points that represent the
playback time range within a Clip. PlayLists are created automatically whenever a new recording is
made; these PlayLists are called real PlayLists. “Real” indicates that the PlayList is created one to one
with a Clip at the same time as the Clip is recorded.
PlayLists can be generated by editing operations in addition to when new recordings are made. One
method of editing is to add a change such as divide, combine, or delete (Fig. 3.1.5.4 to an existing
PlayList. Editing may result in many-to-many relations between real PlayLists and Clips but the valid
part of the clip is always referenced by a real PlayList. Deleting a real PlayList means the Clips which
the PlayList refers to are also erased from the disc.
© Blu-ray Disc Association 2010. All rights reserved.
19
White Paper Blu-ray Disc™ Rewritable Format
User Interface
(1) PlayList and Clip before editing
(2) Divide-operation
Real PlayList
Real PlayList
Clip
Clip
Divide point
Real
PlayList
Real PlayList
No change in Clip layer
Clip
Clip
(3) Combine-operation
Real
PlayList
Combine
Real
PlayList 1
Real
PlayList 2
Clip 1
Clip 2
Real PlayList1
Clip 1
No change in Clip layer
Clip 2
(4) Partial deletion
Delete a portion of Real PlayList
Real PlayList
Clip
Real PlayList
Clip
A portion of Clip
corresponding to
partial deletion is
deleted
Figure 3.1.5.4: Example of editing
There is also the option of creating a new PlayList without altering an existing PlayList. Under the
BD-RE Application Format, this is referred to as creating a virtual PlayList (Fig. 3.1.5.5).
20
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
User Interface
IN1
OUT1
IN2
OUT2
Real PlayList 1
Real PlayList 2
Clip 1
Clip 2
Making a Virtual PlayList which consists of
IN1-OUT1 portion of Real PlayList1 and
IN2-OUT2 portion of Real PlayList2
Virtual PlayList
IN1
OUT1
IN2
PlayItem
OUT2
PlayItem
Real PlayList 1
Real PlayList 2
Clip 1
Clip 2
Figure 3.1.5.5: Creation of Virtual PlayList
New PlayList can be made without any change in existing PlayLists
The virtual PlayList is a sequence of play-items that reference parts of other PlayLists; bridge
sequences, described later, are used to achieve seamless playback even with non-destructive editing.
The BD-RE Application Format provides many other functions to improve ease-of-operation, such
as thumbnails, marks, write protection, and playback-lock of individual discs using passwords.
Thumbnails are small still images and represent directory and PlayList contents in a visual manner.
Under the BD-RE Application Format, thumbnails can be set to represent the entire recorded contents
under the BDAV directory and also individual PlayLists.
A mark is the generic term for an index point that the user sets on the playback timeline to enhance
ease-of-operation. Standard marks provided are bookmarks used for locating specific scenes, skip
marks for skipping certain intervals during playback and resume marks for resuming playback from the
scene where playback was previously stopped. Manufacturers can also add their own mark functions.
Fig. 3.1.5.6 shows the directory/file structure of the BD-RE Application Format where AV streams
and databases are stored.
© Blu-ray Disc Association 2010. All rights reserved.
21
White Paper Blu-ray Disc™ Rewritable Format
User Interface
root
BDAV
Basic BDAV directory
info.bdav
Management information for the parent BDAV directory
menu.tidx
Representative pictures for the parent BDAV directory
menu.tdt1
and/or each PlayList in this BDAV directory are stored as a
menu.tdt2
Thumbnail
mark.tidx
The index information which manages the thumbnail
mark.tdt1
picture of a mark position, and its thumbnail image data
are stored.
mark.tdt2
PLAYLIST
01001.rpls
PlayList file
02002.rpls
PlayList describes construction
information of the PlayList.
10000.vpls
CLIPINF
File extension of “.rpls” shows Real
PlayList and “.vpls” shows Virtual PlayList
:
01000.clpi
Clip Information file。
02000.clpi
One Clip Information file is created for
corresponding Clip AV stream file.
:
Attribute and Characteristic point
Information are stored.
STREAM
01000.m2ts
02000.m2ts
Clip AV stream file
MPEG-2 TS with arrival time stamp is
stored in this file.
:
BDAV1
BDAV2
..
.
Aux BDAV directory
BDAVn
Figure 3.1.5.6: Example of directory and file structure for BD-RE Application format
22
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Editing
6.
Editing
6.1.
Seamless Connection Editing
It is very important for a recording system to have easy-to-use editing functions that enable users to
save wanted sections and cut out unwanted scenes from recorded contents (titles). The BD-RE
Application Format realizes such editing functions through the virtual PlayList. For instance, by using
the virtual PlayList, the user can select highlight scenes from different titles recorded on disc to create
(edit) a new title of highlight scenes and organize/save the new title on disc (Fig. 3.1.5.1, Fig. 3.1.5.5).
As previously described, the BD-RE Application Format adopts MPEG2 and DV formats as its video
recording format (recording codec). When MPEG2 is used for recording, each frame image of the
content is coded into either of three types—I-picture, P-picture, or B-picture—and compressed and
recorded. To give a brief description of the characteristics of the three compressed image types: Ipicture is an image that is coded using only its own data information (intraframe coded picture), Ppicture is an image that is coded based on a prediction of the preceding I-picture or P-picture
(interframe forward-direction predictive coded picture) and B-picture is an image that is coded by
processing the I-picture and P-picture first and then being inserted in between (bi-directional predictive
coded picture). If, as shown in the figure, two scenes are selected from different titles (that is, separate
contents that were recorded at different times) and connected or two scenes separated in time are
selected from the same single recording and connected to create a new title, simply gathering the Clip
AV streams and decoding the streams in succession will cause a break in the MPEG2 compression
pattern at the connection point (editing point) and, as a result, image frames will not be displayed
contiguously. In other words, to display images contiguously even across the point where edited
scenes are connected, the data needs to restructured. The BD-RE Application Format specifies a
structure (mechanism) called a bridge sequence to secure physical contiguousness and ensure
contiguous playback across the editing point. Bridge sequences are managed by the virtual PlayList
which is a logical mechanism. A brief description is provided below of the concept of the bridge
sequence based on Fig. 3.1.6.1.1.
© Blu-ray Disc Association 2010. All rights reserved.
23
White Paper Blu-ray Disc™ Rewritable Format
Editing
IN_time1
OUT_time1
Preceding PlayItem
SPN which indicates the
address of out-point from
this Clip to Bridge Clip
IN_time2
OUT_time2
Succeeding PlayItem
SPN which indicates the
address of in-point from
Bridge Clip to this Clip
Clip 2
Clip 1
Bridge Clip
Seamless connection point of
the preceding PlayItem and the
succeeding PlayItem
Figure 3.1.6.1.1: Bridge sequence
The bridge sequence reconstructs only the required parts as shown in Fig. 3.1.6.1.2 and is designed
to keep data processing of editing points by the recorder to a minimum.
24
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Editing
・・・
Clip 1
I2
B0
B1
Data copied
from Clip 1
B3
Bridge Clip
P5
B3
B4
P8
B6
・・・
(order decoded)
Data copied
from Clip 2
Data reencoded
Data reencoded
B4
B7
P7
B6
i0
p1
p4
b2
b3
B6
B7
b3
b4
p8
b6
b7
Encode type of
original Clip
Seamless
connection point
Clip 2
・・・
b1
p5
b3
b4
p8
b6
b7
i11
b9
b10
p14
b12
b13
・・・
Figure 3.1.6.1.2: Structure of Bridge Clip
During playback, data is decoded in order of Clip 1ÆBridge ClipÆClip 2 as shown in Fig. 3.1.6.1.3
to ensure contiguous playback across the editing point.
© Blu-ray Disc Association 2010. All rights reserved.
25
White Paper Blu-ray Disc™ Rewritable Format
Editing
Title 3
(e.g. Highlight)
Title 1
Title 2
Real PlayList 1
Clip 1
Virtual PlayList
Real PlayList 2
Clip 2
Used for
seamless
connection
Bridge Clip
Figure 3.1.6.1.3: Playback of Bridge sequence
Playback(decode) order is, Clip 1 Î Bridge Clip Î Clip 2.
Seamless playback can be done even on the editing point
6.2.
Audio Dubbing
In general, when recording contents under the BD-RE Application Format, a set of video and audio
data is multiplexed in the transport stream and is recorded as a single Clip. (This transport stream is
called the main-path.) For instance, this mechanism is used for time-shift recording of broadcast
programs.
An important editing function that enhances the recording system is audio dubbing, which allows the
user to easily add other audio data to content after it is recorded. The BD-RE Application Format
realizes an audio dubbing function by providing a mechanism called the sub-path. The sub-path is a
structure that enables the user to select a separate stream during playback of a Clip on the main-path
and play back the stream simultaneously with data on the main-path or by itself. For instance, this
functionality can be used with content on which audio dubbing was performed to play back the audio
data on the main-path and the audio data of a separate Clip on the sub-path at the same time or singly.
Fig. 3.1.6.2.1 shows the relation between the main-path and the sub-path. The playback function of
dubbed audio is optional.
26
© Blu-ray Disc Association 2010. All rights reserved.
White Paper Blu-ray Disc™ Rewritable Format
Editing
Virtual PlayList
PlayItem (main-path)
Sub-PlayItem
(sub-path)
IN1
OUT1
IN2
OUT2
Real PlayList 1
Peal PlayList 2
Clip 1
Clip 2
Figure 3.1.6.2.1: main-path/sub-path
Stream which is decoded synchronously with main video
and audio can be referred by Sub-PlayItem
As shown in the figure, a sub-play-item is logically added to the play-item in the virtual PlayList to
associate a separate Clip (sub-path) to the play-item on the main-path. The playback start time of the
sub–play-item can be associated with the playback time (pts) of the play-item on the main-path. The
recorder determines differences (such as the PCR value) in the timelines of the Clips on the main-path
and the sub-path during playback and commences decoding.
© Blu-ray Disc Association 2010. All rights reserved.
27
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising