Overview of H.264 / MPEG-4 Part10

1
Overview of H.264 /MPEG-4 Part10
2004. 10. 20.
Soon-kak Kwon, A. Tamhankar, K. R. Rao Dongeui
University, T-Mobile, University of Texas at
Arlington
2
Contents

1. Introduction
2. Layered Structure
3. Video Coding Algorithm
4. Error Resilience
5. Comparison of Coding Efficiency
6. Conclusions

3
Introduction

• Scope of Image and Video Coding Standards
• Only the Syntax and Decoder are standardized
• Optimization beyond the obvious
• Complexity reduction for implementation
• Provides no guarantees of quality

Input (image / video)
Pre-Processing
Encoding
Output (image / video)
Post-Processing Error Recovery
Decoding
Scope of Standard
4
Introduction

• Video Coding Standards

Year
Main Applications
Standard
1992-1999, 2000
Image
JPEG, JPEG2000
1995-2000
Fax
JBIG
1990
Video Conferencing
H.261
1995, 2000
DTV, SDTV
H.262, H.262
1998, 2000
Videophone
H.263, H.263
1992
Video CD
MPEG-1
1995
DTV, SDTV, HDTV, DVD
MPEG-2
2000
Interactive video
MPEG-4
Multimedia Content description Interface
2001
MPEG-7
2002
Multimedia Framework
MPEG-21
2003
Advanced Video Coding
H.264/MPEG-4 part 10
Fidelity Range Extensions (High profile), Studio
editing, Post processing, Digital cinema
2004 August
5
Introduction

• MPEG-1
• Formally ISO/IEC 11172-2 (93), developed by
  ISO/IEC JTC1 SC29 WG11 (MPEG) use is fairly
  widespread, but mostly overtaken by MPEG-2
• Superior quality compared to H.261 when operated
  at higher bit rates ( ? 1Mbps for CIF 352x288
  resolution)
• Provides approximately VHS quality between
  1-2Mbps using SIF 352x240/288 resolution
• Additional technical features
• Bi-directional motion prediction (B-pictures)
• Half-pel motion vector resolution
• Slice-structured coding
• DC-only D pictures

6
Introduction

• Predictive Coding with B Pictures

I
B
P
B
P
7
Introduction

• MPEG-2 / H.262
• Formally ISO/IEC 13818-2 ITU-T H.262,
  developed (1994) jointly by ITU-T and ISO/IEC
  SC29 WG11 (MPEG) Now in wide use for DVD and
  standard high-definition DTV (the most commonly
  used video coding standard)
• Primary new technical features
• Support for interlaced-scan pictures
• Also
• Various forms of scalability (SNR, Spatial,
  Temporal and hybrid)
• I-picture concealment motion vectors
• Essentially same as MPEG-1 for progressive-scan
  pictures, and MPEG-1 forward compatibility is
  required
• Not especially useful below 2-3Mbps (range
  2-5Mbps SDTV broadcast, 6-8Mbps DVD, 18Mbps
  HDTV), picture skipping not easy

8
Introduction

• H.263 The Next Generation
• ITU-T Rec. H.263 (v1 1995) The next generation
  of video coding performance, developed by ITU-T
  the current premier ITU-T video standard (has
  overtaken H.261 as dominant videoconferencing
  codec)
• Superior quality to prior standards at all bit
  rates (except perhaps for interlaced video)
• Wins by a factor of two at very low rates
• Version 2 (late 1997 / early 1998) version 3
  (2000) later developed with a large number of new
  features
• Profiles defined early 2001
• H.263 H.263 (Extensions to H.263)

9
Introduction

• MPEG-4 Visual Baseline H.263 and Many Creative
  Extras
• MPEG-4 Visual (formally 14496-2, v1 early 1999)
  Contains the H.263 baseline design and adds
  essentially all prior features and many creative
  new extras
• Segmented coding of shapes
• Scalable wavelet coding of still textures
• Mesh coding
• Face animation coding
• Coding of synthetic and semi-synthetic content
• 10 12-bit sampling
• More
• v2 (early 2000) v3 (early 2001) added later

10
Introduction

• Relationship to Other Standards
• Same design to be approved in both ITU-T / VCEG
  and ISO/IEC / MPEG
• In ITU-T / VCEG this is a new separate standard
• ITU-T Recommendation H.264
• ITU-T Systems (H.32x) is modified to support it
• In ISO/IEC / MPEG this is a new part in the
  MPEG-4 suite
• Separate coded design from prior MPEG-4 visual
  (Part 2)
• New part 10 called Advanced Video Coding (AVC
  similar to AAC MPEG-2 as separate audio codec)
• Not backward or forward compatible with prior
  standards
• MPEG-4 Systems / File Format modifying to support
  it
• H.222.0 MPEG-2 Systems are also be modified to
  support it
• IETF working on RTP payload packetization

11
Introduction

• History of H.264 / MPEG-4 part 10
• ITU-T Q.6/SG16 started work on H.26L (L Long
  Range)
• July 2001 H.26L demonstrated at MPEG (Moving
  Picture Experts Group) call for technology
• December 2001 ITU-T VCEG (Video Coding Experts
  Group) and ISO/IEC MPEG started a joint project
  Joint Video Team (JVT)
• May 2003 Final approval from ISO/IEC and ITU-T
• The standard is named H.264 by ITU-T and MPEG-4
  part 10 by ISO/IEC
• Fidelity Range Extensions (August 2004) Amendment
  1
• Transport of MPEG-4 AVC on MPEG-2 TS Amendment 3

12
Introduction

• Purpose of H.264 / MPEG-4 part 10
• Higher coding efficiency than previous standards,
  MPEG-1,2,4 part 2, H.261, H.263
• Simple syntax specifications
• Seamless integration of video coding into all
  current protocols
• More error robustness
• Various applications like video broadcasting,
  video streaming, video conferencing, D-Cinema,
  HDTV
• Network friendliness
• Balance between coding efficiency, implementation
  complexity and cost - based on state-of the-art
  in VLSI design technology

13
Introduction

• H.264 / MPEG-4 part 10 Architecture

14
Introduction

• Applications of H.264 / MPEG-4 part 10 A Broad
  range of applications for video content including
  but not limited to the following
• Video Streaming over the internet
• CATV Cable TV on optical networks, copper, etc.
• DBS Direct broadcast satellite video services
• DSL Digital subscriber line video services
• DTTB Digital terrestrial television broadcasting,
  cable modem, DSL
• ISM Interactive storage media (optical disks,
  etc.)
• MMM Multimedia mailing
• MSPN Multimedia services over packet networks
• RTC Real-time conversational services
  (videoconferencing, videophone, etc.)
• RVS Remote video surveillance
• SSM Serial storage media (digital VTR, etc.)
• D Cinema Content contribution, content
  distribution, studio editing, post processing

15
Introduction

• Profiles and Levels for particular applications
• Profile a subset of entire bit stream of
  syntax,
• different decoder design based on the
  Profile
• Four profiles Baseline, Main, Extended and High

Applications
Profile
Video Conferencing Videophone
Baseline
Digital Storage Media Television Broadcasting
Main
Streaming Video
Extended
High
Content contribution Content distribution Studio
editing Post processing
16
Introduction

• Specific coding parts for the Profiles

17
Introduction

• Common coding parts for the Profiles
• I slice (Intra-coded slice) the coded slice by
  using prediction only from decoded samples within
  the same slice
• P slice (Predictive-coded slice) the coded
  slice by using inter prediction from
  previously-decoded reference pictures, using at
  most one motion vector and reference index to
  predict the sample values of each block
• CAVLC (Context-based Adaptive Variable Length
  Coding) for entropy coding

18
Introduction

• Coding parts for Baseline Profile
• Common parts I slice, P slice, CAVLC
• FMO Flexible macroblock order macroblocks may
  not necessarily be in the raster scan order. The
  map assigns macroblocks to a slice group
• ASO Arbitrary slice order the macroblock
  address of the first macroblock of a slice of a
  picture may be smaller than the macroblock
  address of the first macroblock of some other
  preceding slice of the same coded picture
• RS Redundant slice This slice belongs to the
  redundant coded data obtained by same or
  different coding rate, in comparison with
  previous coded data of same slice

19
Introduction

• Coding parts for Main Profile
• Common parts I slice, P slice, CAVLC
• B slice (Bi-directionally predictive-coded slice)
  the coded slice by using inter prediction from
  previously-decoded reference pictures, using at
  most two motion vectors and reference indices to
  predict the sample values of each block
• Weighted prediction scaling operation by
  applying a weighting factor to the samples of
  motion-compensated prediction data in P or B
  slice
• CABAC (Context-based Adaptive Binary Arithmetic
  Coding) for entropy coding

20
Introduction

• Coding parts for Extended Profile
• Common parts I slice, P slice, CAVLC
• SP slice the specially coded slice for
  efficient switching between video streams,
  similar to coding of a P slice
• SI slice the switched slice, similar to coding
  of an I slice
• Data partition the coded data is placed in
  separate data partitions, each partition can be
  placed in different layer unit
• Flexible macroblock order (FMO)
• Arbitrary slice order (ASO)
• Redundant slice (RS)
• B slice
• Weighted prediction

21
Introduction

• Profile specifications

High
Extended
Main
Baseline
X
X
X
I P Slices
X
X
X
X
Deblocking Filter
X
X
X
X
¼ Pel Motion Compensation
X
X
X
X
Variable Block Size (16x16 to 4x4)
X
X
X
X
CAVLC/UVLC
X
X
X
Error Resilience Tools Flexible MB Order, ASO,
Red. Slices
X
SP/SI Slices
X
X
X
B Slice
X
X
X
Interlaced Coding
X
X
CABAC
X
Data Partitioning
22
Introduction
 
 

• Application requirements

 
 
23
Introduction

• Level corresponding to processing power and
  memory capability of a codec

24
Introduction

• Parameter set limits for each Level

25
Layered Structure

• Two Layers Network Abstraction Layer (NAL),
  Video Coding Layer (VCL)
• NAL
• Abstracts the VCL data hence the name Network
  Abstraction Layer
• Header information about the VCL format
• Appropriate for conveyance by the transport
  layers or storage media
• NAL unit (NALU) defines a generic format for use
  in both packet based and bit-streaming systems
• VCL
• Core coding layer
• Concentrates on attaining maximum coding
  efficiency

26
Layered Structure

• Elements of VCL

27
Layered Structure

• Supporting picture format 420 chroma sampling
• CIF
• Format
• QCIF
• format

28
Video Coding Algorithm

• Block diagram for H.264 encoder

29
Video Coding Algorithm

• Block diagram for H.264 Decoder

30
VC Algorithm Intra Prediction

• Exploits Spatial redundancy between adjacent
  macroblocks in a frame
• 4 x 4 luma block
• 9 prediction modes 8 Directional predictions
  and 1 DC prediction
• (vertical 0, horizontal 1, DC 2,
  diagonal down left 3, diagonal down right 4,
• vertical right 5, horizontal down
  6, vertical left 7, horizontal up 8)

samples a, b, , p the predicted ones for the
current block, above and left samples A, B, , M
previously reconstructed ones
31
VC Algorithm Intra Prediction

• Example of 4 x 4 luma block
• Sample a, d predicted by round(I/4 M/2
  A/4), round(B/4 C/2 D/4) for mode 4
• Sample a, d predicted by round(I/2 J/2),
  round(J/4 K/2 L/4) for mode 8

32
VC Algorithm Intra Prediction

• 16 x 16 luma
• 4 prediction modes
• (vertical 0, horizontal 1, DC 2, plane 3)
• Plane works well in smoothly varying luminance.
• A linear plane function is fitted to the upper
  (H) and left side (V) samples
• (8x8) luma (FRExt only) similar to 4x4 luma with
  low pass filtering of the predictor to improve
  prediction performance

Plane
33
VC Algorithm Intra Prediction

• Chroma always operates using full MB prediction
• (8x8) 420 Format
• (8x16) 422
• (16x16) 444
• (Similar to 16x16 luma block but different mode
  order)
• 4 Prediction modes
• (DC 0, Horizontal 1, Vertical 2, Plane 3)

34
VC Algorithm Inter Prediction

• Exploits temporal redundancy
• Prediction of variable block sizes
• Sub-pel motion compensation
• Deblocking filter
• Management of multiple reference pictures

35
VC Algorithm Inter Prediction

• Prediction of variable block size
• A MB can be partitioned into smaller block sizes
• 4 cases for 16 x 16 MB, 4 cases for 8 x 8 Sub-MB
• Large partition size homogeneous areas, small
  detailed areas
• Cannot mix the two partitions .i.e. cannot have
  16x8 and 4x8 partitions
• When sub-MB partition (8x8) is selected, the
  (8x8) block can be further partitioned

36
VC Algorithm Inter Prediction

• Sub-pel motion compensation
• Better compression performance than integer-pel
  MC
• Expense of increased complexity
• Outperforms at high bit rates and high
  resolutions

37
VC Algorithm Inter Prediction

• Sub-pel accuracy
• A distinct MV can be sent for each sub-MB
  partition. ME can be based on multiple pictures
  that lie in the past or in the future in display
  order. Reference picture for ME is selected at
  the MB partition level. Sub-MB partitions within
  the same MB partition must use the same reference
  picture.

38
VC Algorithm Inter Prediction

• Half-pel interpolated from neighboring
  integer-pel samples using a 6-tap Finite Impulse
  Response filter with weights (1, -5, 20, 20, -5,
  1)/32
• Quarter-pel produced using bilinear
  interpolation between neighboring half- or
  integer-pel samples

b round((E-5F20G20H-5IJ)/32) a
round((Gb)/2)
39
VC Algorithm Inter Prediction

• Deblocking filter Adaptive
• To reduce the blocking artifacts in the block
  boundary and prevent the propagation of
  accumulated coded noise
• Filtering is applied to horizontal or vertical
  edges of 4 x 4 blocks in a macroblock, adaptively
  on the several levels (slice, block-edge,
  sample)

40
VC Algorithm Inter Prediction

• Management of multiple reference pictures
• To take care of marking some stored pictures as
  unused and deciding which pictures to delete
  from the buffer

Bitstream Output
Video Input

Transform Quantization
Entropy Coding
-
Inverse Quantization Inverse Transform


Intra/Inter Mode Decision
Motion Compensation
Intra Prediction
Deblocking Filtering
Picture Buffering
Motion Estimation
41
VC Algorithm Transform Quantization

• Transform
• Integer transform, multiplier free additions
  and shifts in 16-bit arithmetic
• Hierarchical structure 4 x 4 Integer DCT
  Hadamard transform

Assignment of the indices of DC (dark samples) to
luma 4 x 4 block, the numbers 0, 1, , 15 are
the coding order for (4x4) integer DCT transform
(0,0), (0,1), (0,2), , (3,3) are DC coefficients
of each 4x4 block
Hadamard transform is applied only when (16x16)
intra prediction mode is used with (4x4) IntDCT.
Similarly for the chroma MB size for chroma
depends on 420, 422 and 444 formats
42
VC Algorithm Transform

• 4 x 4 integer DCT
• X input pixels, Y output coefficients
• Y(Cf x CfT) Ef

43
4x4 Inverse IntDCT
Here
In both forward and inverse transforms QP
(Quantization step) is embedded in matrices Ef
and Ei
44
VC Algorithm Transform

• Luma DC coefficients for Intra 16x16 MB
• 16 DC coefficients of 16 (4x4) blocks are
  transformed using Walsh Hadamard transform

YD
where // rounding to the nearest integer
45
VC Algorithm Transform

• Chroma DC coefficients Intra pediction mode (4x4)
  IntDCT
• Walsh Hadamard transform 2 x 2 DC coefficients

, 420
V
U
16
17
2x2 DC
22
19
23
18
AC
20
21
24
25
For 422 and 444 chroma formats Hadamard block
size is increased.
46
VC Algorithm Transform

• Block diagram emphasizing transform

Bitstream Output
Video Input

Transform Quantization
Entropy Coding
-
Inverse Quantization Inverse Transform

• 4 x 4 integer DCT transform
• H
• - Hadamard transform of DC coefficients
• for 16 x 16 Intra luma and 8 x 8 chroma blocks

Intra/Inter Mode Decision
Motion Compensation
Intra Prediction
Deblocking Filtering
Picture Buffering
Motion Estimation
47
VC Algorithm Quantization

• Multiplication operation for the exact transform
  is combined with the multiplication of scalar
  quantization
• Encoder post-scaling and quantization
• Decoder inverse quantization and pre-scaling

X quantizer input Y quantizer output Qstep
quantization parameter, a total of 52 values,
doubles in size for every increment
of 6 in QP 8 for bits per decoded sample. FRExt
expands QP beyond 52 by 6 for each additional bit
of decoded sample SF scaling term
48
VC Algorithm Transform, Quantization

• Rescale and Inverse transform
• Intra (16x16) prediction mode only

49
VC Algorithm Entropy Coding

• All syntax elements other than residual transform
  coefficients are encoded by the Exp-Golomb codes
  (UVLC)
• Scan order to read the residual data (quantized
  transform coefficients) zig-zag, alternate
• Context-based Adaptive Variable Length Coding
  (CAVLC) in All Profiles
• Context-based Adaptive Binary Arithmetic Coding
  (CABAC) in Main Profile

Alternate scan
Zig-zag scan
50

• Exponential Golomb codes (for data elements other
  than tansform coefficients these codes are
  actually fixed, and are also called Universal
  Variable Length Codes (UVLC))

51

• These are variable length codes with a regular
  construction
• M Zeroes 1 INFO
• INFO is an M-bit carrying information.
• The first codeword as no leading zero or
  trailing info.
• Code words 1 and 2 have a single-bit INFO field,
  code words 3-6 have a two-bit INFO field and so
  on.
• The length of each Exp-Golomb codeword is (2M1)
  bits.
• M Floor (Log2 code_num 1)
• INFO code_num 1 2M

52
Decoding

• Read in M leading zeroes followed by 1
• Read in M-bit INFO field
• Code_num 2M INFO 1
• (For codeword 0, INFO and M are zero)
• CAVLC Codes transform coefficients
• CABAC Codes transform coefficients and MV
• All other syntax elements are coded with the
  Exp_Golomb codes

53
VC Algorithm Entropy Coding

• CAVLC handles the zero and /-1 coefficients as
  the different manner with the levels of
  coefficients. The total numbers of zeros and /-1
  are coded. For the other coefficients, their
  levels are coded.
• Encoding steps
• step 1 encode the total number of nonzero
  coefficients and /-1 (trailing ones) values
• step 2 encode the sign of each trailing one in
  reverse order
• step 3 encode the levels of the remaining
  non-zero coefficients in reverse order
• step 4 encode the total number of zeros before
  the last coefficient
• step 5 encode each run of zeros
• H.264 maintains 11 different sets of codes (4 for
  of coefficients and 7 for the actual
  coefficients)
• These are adopted to the current stream or
  context (thus CAVLC)

54
VC Algorithm Entropy Coding

• Example of CAVLC

order
0 1 2 3 4 5 6 7 8 9 16
c0 c1 c2 0 1 1 0 1 0 0 0
coeff.
Step 1 encode for no. of nonzero total
coefficients and 1 or 1 (trailing ones)
from look-up table
no. of nonzero total coefficients 6 (order 0,
1, 2, 4, 5, 7) no. of trailing ones 3 (order
4, 5, 7)

Step 2 encode for sign of trailing one in
reverse order
- (order 7) , (order 5), (order 4)
Step 3 encode for level of remaining non-zero
coefficients in reverse order
c2 (order 2), c1, c0
Step 4 encode for total no. of zeros before the
last coefficient
2 (order 3, 6)
Step 5 encode for run of zeros in reverse order
1 (order 6-5), 0 (order 4), 1 (order 3-2)
55
VC Algorithm Entropy Coding

• CABAC utilizes the arithmetic coding, also in
  order to achieve good compression, the
  probability model for each symbol element is
  updated. Both MV and residual transform
  coefficients are coded by CABAC.
• Encoding steps
• step 1 context modeling Choose a suitable
  model
• step 2 binarization If a symbol is non-binary
  valued it will be mapped into a sequence of
  binary decisions called bins
• step 3 binary arithmetic coding using
  probability estimates provided by context modeling

56
CABAC increases compression efficiency by 10
over CAVLC but computationally more intensive
57
VC Algorithm B Slice

• Generalized Bidirectional prediction
• Supports not only forward/backward prediction
  pair, but also forward/forward and
  backward/backward pairs
• Direct mode
• Derives reference picture, block size, and motion
  vector data from the subsequent inter picture.
• Weighted prediction
• Scaling operation by applying a weighting factor
  to the samples of motion-compensated prediction
  data in P or B slice.
• Pictures coded using B slices can be used as
  references for decoding of subsequent pictures in
  decoding order (with an arbitrary relationship to
  such pictures in display order)

58
VC Algorithm B Slice

• Generalized Bidirectional prediction
• Multiple reference pictures mode
• Two forward references proper for a region just
  before scene change
• Two backward references proper for a region
  just after scene change

59
VC Algorithm B Slice

• Direct mode
• Forward / backward pair of bi-directional
  prediction
• Prediction signal is calculated by a linear
  combination of two blocks that are determined by
  the forward and backward motion vectors pointing
  to two reference pictures.

mvL0 tb ? mvCol / td mvL1 (td tb) ?
mvCol / td where mvCol is a MV used in the
co-located MB of the subsequent picture
60
VC Algorithm B Slice

• Weighted prediction
• Different weights of reference signals for
  gradual transitions from scene to scene, i.e.,
  fade to black (the luma samples of the scene
  gradually approach zero), fade from black
• Different weighted prediction method for a
  macroblock of P slice or B slice
• A prediction signal p for B slice is obtained by
  different weights from two reference signals, r1
  and r2. 
• p w1 ? r1 w2 ? r2
• where w1 and w2 are weighting factors
• Implicit type the factors are calculated based
  on the temporal distance between the pictures
• Explicit type the factors are transmitted in
  the slice header

61
VC Algorithm SP and SI Slices (Extended profile
only)

• Switched slice
• SP slice the specially coded slice for
  efficient switching between video streams,
  similar to coding of a P slice
• SI slice the switched slice, similar to coding
  of an I slice

Allows bit stream switching and additional
functionalities such as random access, fast
forward, reverse and stream splicing.
62
Error Resilience

• Parameter setting
• Flexible macroblock ordering (FMO)
• Redundant slice methods
• Switched slice SP/SI
• Data partitioning
• Arbitrary Slice Order ASO

Only in Extended Profile

63
Data partitioning slices (Extended profile only)

1. Coded data of a slice is placed in three separate
   data partitions A,B C.
2. A has slice header and header data for each MB in
   the splice
3. B has coded residual data for intra and SI slice
   MBs
4. C has coded residual data for inter coded MB
5. Place each partition A, B C in a separate NAL
   unit and transport separately

64
Error Resilience Parameter setting

• The sequence parameter set contains all
  information related to a sequence of pictures
• a picture parameter set contains all information
  related to all the slices belonging to a single
  picture.
• The encoder chooses the appropriate picture
  parameter set to use by referencing the storage
  location in the slice header of each coded slice.

H.264 Encoder
H.264 Decoder
VCL Data transfer with PS 3
1
2
3
3
2
1
Reliable Parameter Set Exchange

• Parameter Set 3
• Video format NTSC
• Motion Resolution ¼
• Enc CABAC
• Frame width 11

65
Error Resilience FMO

• Flexible macroblock ordering allows to assign
  macroblocks to slices in an order other than the
  scan order.
• Assume that all macroblocks of the picture are
  allocated either to slice group 0 or slice group
  1, and the macroblocks in each slice group are
  dispersed through the picture.
• If the packet containing the information of slice
  group 1 is lost during transmission, then the
  lost macroblock can be recovered by the error
  concealment mechanism, since every lost
  macroblock has several spatial neighbors that
  belong to the other slice.
• ASO is similar to FMO. Randomizes data prior to
  transmission. Errors are distributed more
  randomly over the video frames rather than in a
  single block of data.

66
Error Resilience Redundant Slice

• Redundant slices allow to place one or more
  redundant representations of the same
  macroblocks.
• For example, the primary representation can be
  coded with a low quantization parameter (hence in
  good quality), whereas the redundant slice can be
  coded with a high quantization parameter (hence,
  in a much coarser quality, but also utilizing
  fewer bits).
• A decoder reacts to redundant slices by
  reconstructing only the primary slice, if it is
  available, and discarding the redundant slice.
  However, if the primary slice is missing, the
  redundant slice can be reconstructed.

67
Comparison of Coding Efficiency
 

• Subjective verification test
• Comparison of the H.264 Baseline Profile (BP) and
  MPEG-4 part 2 Simple Profile (SP) for the
  multimedia definition (MD). The numbers in the
  table indicate the coding efficiency improvement
  achieved by the H.264 where the codecs being
  compared provide statistically equivalent picture
  quality. The letter T indicates that H.264
  achieved transparency.
• H.264 Baseline Profile achieves a coding
  efficiency improvement of 2 times or greater in
  14 out of 18 statistically conclusive cases.

 
68
Comparison of Coding Efficiency
 
 

• Subjective verification test
• Comparison of H.264 Main Profile (MP) and MPEG-4
  Part 2 Advanced Simple Profile (ASP) for the MD.
• H.264 Main Profile achieves a coding efficiency
  improvement of 2 times or greater in 18 out of 25
  statistically conclusive cases.

 
 
69
Comparison of Coding Efficiency
 
 
 

• Subjective verification test
• Comparison of H.264 Main Profile and MPEG-2 for
  the Standard Definition (SD)
• When compared to MPEG-2 HiQ (real-time High
  Quality), H.264 Main Profile achieves a coding
  efficiency improvement of 1.5 times or greater in
  8 out of 12 statistically conclusive cases.
• When compared to MPEG-2 TM5, H.264 Main Profile
  achieves a coding efficiency improvement of 1.8
  times or greater in 9 out of 12 statistically
  conclusive cases.

 
 
 
70
Comparison of Coding Efficiency
 
 
 
 

• Subjective verification test
• Comparison of H.264 Main Profile and MPEG-2 for
  the High Definition (HD)
• When compared to MPEG-2 HiQ, H.264 Main Profile
  achieves a coding efficiency improvement of 1.7
  times or greater in 7 out of 9 statistically
  conclusive cases.
• When compared to MPEG-2 TM5, H.264 Main Profile
  achieves a coding efficiency improvement of 1.7
  times or greater in 8 out of 9 statistically
  conclusive cases.

 
 
 

71
Comparison of Coding Efficiency
 
 
 
 

• Objective test
• PSNR (between original and reconstructed
  pictures) and bitrate saving results of Tempete
  CIF 15Hz sequence for the video streaming
  application

 
 
HLP High Latency Profile ASP Advanced
Simple Profile H.26L H.264 Main Profile

72
Comparison of Coding Efficiency
 
 
 
 

• Objective test
• PSNR and bitrate saving results of Paris CIF
  15Hz sequence for the video conferencing
  application

CHC Conversational High Compression SP Simple
Profile ASP Advanced Simple Profile H.26L
H.264 Baseline Profile
 
 

73
Conclusions
 
 
 
 

• H.264 outperforms over the previous standards
• Comparison of standards

Feature/Standard MPEG-1 MPEG-2 MPEG-4 part 2 (visual) H.264/MPEG-4 part 10
Macroblock size 16x16 16x16 (frame mode) 16x8 (field mode) 16x16 16x16
Block Size 8x8 8x8 16x16, 16x8, 8x8 16x16, 8x16, 16x8, 8x8, 4x8, 8x4, 4x4
Transform 8x8 DCT 8x8 DCT 8x8 DCT/Wavelet 4x4, 8x8 Int DCT 4x4, 2x2 Hadamard
Quantization Scalar quantization with step size of constant increment Scalar quantization with step size of constant increment Vector quantization Scalar quantization with step size increase at the rate of 12.5
Entropy coding VLC VLC VLC VLC, CAVLC, CABAC
Motion Estimation Compensation Yes Yes Yes Yes, more flexible Up to 16 MVs per MB
Playback Random Access Yes Yes Yes Yes

 
 

74
Conclusions
 
 
 
 

• Comparison of standards (continued)

Feature/Standard MPEG-1 MPEG-2 MPEG-4 part 2 (visual) H.264/MPEG-4 part 10
Pel accuracy Integer, ½-pel Integer, ½-pel Integer, ½-pel, ¼-pel Integer, ½-pel, ¼-pel
Profiles No 5 8 4
Reference picture one one one multiple
Bidirectional prediction mode forward/backward forward/backward forward/backward forward/forward forward/backward backward/backward
Picture Types I, P, B, D I, P, B I, P, B I, P, B, SP, SI
Error robustness Synchronization concealment Data partitioning, FEC for important packet transmission Synchronization, Data partitioning, Header extension, Reversible VLCs Data partitioning, Parameter setting, Flexible macroblock ordering, Redundant slice, Switched slice
Transmission rate Up to 1.5Mbps 2-15Mbps 64kbps - 2Mbps 64kbps -240Mbps
Compatibility with previous standards n/a Yes Yes No
Encoder complexity Low Medium Medium High

 
 

75
Conclusions
 
 
 
 

• Currently the commercial H.264 codecs are widely
  developed by several companies for replacing /
  complementing existing products.
• Related companies
• UBVideo website http//www.ubvideo.com
• LSI Logic website http//www.lsilogic.com
• Microsoft website http//www.microsoft.com
• Envivio website http//www.envivio.com
• Broadcom website http//www.broadcom.com
• Nagravision website http//www.nagravision.com
• Philips website http//www.philips.com
• Polycom website http//www.polycom.com
• PixelTools Corporation website
  http//www.pixeltools.com
• Amphion website http//www.amphion.com

 
 

76
Conclusions
 
 
 
 

• Related companies (continued)
• Ligos Corporation website http//www.ligos.com
• LifeSize website http//www.lifesize.com
• Netvideo website http//www.netvideo.com
• Motorola website http//www.motorola.com
• Vanguard Software Solutions website
  http//www.vsofts.com
• STMicroelectronics website http//us.st.com
• MainConcept website http//www.mainconcept.com
• Impact Labs Inc. website http//www.impactlabs.co
  m
• Sorenson media AVC Pro codec (H.264)
• Blu-Ray Disc Association (BDA) MPEG-4 AVC High
  Profile and Microsofts VC-1 video codec (based
  on Windows Media Video 9 codec) mandatory
  (blu-ray Disc BD-ROM specification)

 
 

77
Conclusions
 
 
 
 

• Related group
• MPEG website http//www.mpeg.org
• JVT website ftp//standards.polycom.com
• www.mpegif.org
• Test software
• http//iphome.hhi.de/suehring/tml/download
• H.264/AVC JM Software http//bs.hhi.de/suehring/
  tml/download
• Test sequences
• http//ise.stanford.edu/video.html
• http//kbs.cs.tu-berlin.de/stewe/vceg/sequences.h
  tm
• http//www.its.bldrdoc.gov/vqeg
• ftp.tnt.uni-hannover.de/pub/jvt/sequences/
• http//trace.eas.asu.edu/yuv/yuv.html

 
 

78
Conclusions
 
 
 
 

• H.264 licensing MPEG LA and Via Licensing are
  now coordinating the licensing terms,
  decoder-encoder royalties for product
  manufacturers and participation fees for video
  streaming services regardless of Profile(s)
• MPEG LA website http//www.mpegla.com
• Via Licensing http//www.vialicensing.co
  m
• FRExtensions
• to 422 and 444 chroma formats
• 12 bit resolution for medical imaging
• Scalable coding/ Lossless coding for digital
  cinema application
• High fidelity coding for the next generation
  optical discs
• Extension for various applications H. Schwartz,
  D. Marpe and T. Wiegand, SNRscalable extension
  of H.264/AVC, ICIP 2004, vol. , pp. ,
  Singapore, Oct. 2004.
• FINAL STAGES OF APPROVAL
• Standard systems and file format support
  specifications
• Standardizing reference software implementation
• Standardizing conformance bit streams and
  specifications

 
 

79
Contacts for Further Information
 
 
 
 

• JVT documents and software on open ftp website
  ftp//standards.polycom.com
• http//iphome.hhi.de/suehring
• JVT reflector subscription
• http/mail.imtc.org/cgi-bin/lyris.pl?enterjvt-ex
  perts
• JVT reflector e-mail
• jvt-experts_at_mail.imtc.org
• JVT management team
• Chair Gary Sullivan (garysull_at_microsoft.com)
• Co-chair Ajay Luthra (aluthra_at_motorola.com)
• Co-chair Thomas Wiegand (wiegand_at_hhi.de)
• Dr. K. R . Rao, UTA rao_at_uta.edu
• Dr. S. K. Kwon, Dongeui University
  skkwon_at_dongeui.ac.kr
• Ms. A. Tamhankar, T-Mobile arundhati_at_ieee.org
• Karsten.suehring_at_hhi.fraunhofer.de

 
 

80
References
1 MPEG-2 ISO/IEC JTC1/SC29/WG11 and ITU-T,
ISO/IEC 13818-2 Information Technology-Generic
Coding of Moving Pictures and Associated Audio
Information Video, ISO/IEC and ITU-T, 1994.
2 MPEG-4 ISO/IEC JTCI/SC29/WG11, ISO/IEC 14
4962000-2 Information on Technology-Coding of
Audio-Visual Objects-Part 2 Visual, ISO/IEC,
2000. 3 H.263 International
Telecommunication Union, Recommendation ITU-T
H.263 Video Coding for Low Bit Rate
Communication, ITU-T, 1998. 4 H.264
International Telecommunication Union,
Recommendation ITU-T H.264 Advanced Video
Coding for Generic Audiovisual Services, ITU-T,
2003. 5 T. Stockhammer, M. Hannuksela, and S.
Wenger, H.26L/JVT Coding Network Abstraction
Layer and IP-based Transport, IEEE ICIP 2002,
Rochester, New York, Vol. 2, pp. 485-488, Sep.
2002.
81
6 P. List, A. Joch, J. Lainema, G. Bjontegaard,
and M. Karczewicz, Adaptive Deblocking Filter,
IEEE Trans. CSVT, Vol. 13, pp. 614-619, July
2003. 7 K. R. Rao and P. Yip, Discrete Cosine
Transform, Academic Press, 1990. 8 I. E.G.
Richardson, H.264 and MPEG-4 Video Compression
Video Coding for Next-generation Multimedia,
Wiley, 2003. 9 H. S. Malvar, A. Hallapuro, M.
Karczewicz, and L. Kerofsky, Low-Complexity
Transform and Quantization in H.264/AVC, IEEE
Trans. CSVT, Vol. 13, pp. 598-603, July
2003. 10 S. W. Golomb, Run-Length Encoding,
IEEE Trans. on Information Theory, IT-12, pp.
399-401, December 1966. 11 D. Marpe, H.
Schwarz, and T. Wiegand, Context-Based Adaptive
Binary Arithmetic Coding in the H.264/AVC Video
Compression Standard, IEEE Trans. CSVT, Vol. 13,
pp. 620-636, July 2003.
82
12 M. Flierl and B. Girod, Generalized B
Picture and the Draft H.264/AVC Video-Compression
Standard, IEEE Trans. CSVT, Vol. 13, pp.
587-597, July 2003. 13 M. Karczewicz and R.
Kurceren, The SP- and SI-Frames Design for
H.264/AVC, IEEE Trans. CSVT, Vol. 13, pp.
637-644, July 2003. 14 S. Wenger, H.264/AVC
Over IP, IEEE Trans. CSVT, Vol. 13, pp. 645-656,
July 2003. 15 ISO/IEC JTC1/SC29/WG11, Report
of The Formal Verification Tests on AVC
(ISO/IEC14496-10 ITU-T Rec. H.264),
MPEG2003/N6231, December 2003. 16 M. Ghanbari,
Standard Codecs Image Compression to Advanced
Video Coding, Hertz, UK IEE, 2003. 17 A.
Joch, F. Kossentini, H. Schwarz, T. Wiegand, and
G. J. Sullivan, Performance Comparison of Video
Coding Standards using Lagrangian Coder Control,
IEEE ICIP 2002, Rochester, New York, Vol. 2, pp.
501-504, Sept. 2002.
83
18 T. Wiegand, G. J. Sullivan, G. Bjontegaard,
and A. Luthra, Overview of the H.264/AVC Video
Coding Standard, IEEE Trans. CSVT, Vol. 13, pp.
560-576, July 2003. 19 MPEG website
http//www.mpeg.org 20 JVT website
ftp//standards.polycom.com 21 MPEG LA website
http//www.mpegla.com 22 H.264 / AVC JM
Software http//bs.hhi.de/suehring/tml/download
23 UBVideo website http//www.ubvideo.com 24
LSI Logic website http//www.lsilogic.com 25
Microsoft website http//www.microsoft.com 26
Envivio website http//www.envivio.com 27
PixelTools Corporation website
http//www.pixeltools.com 28 Nagravision
website http//www.nagravision.com 29 Philips
website http//www.philips.com
84
30 Polycom website http//www.polycom.com 31
MainConcept website http//www.mainconcept.com
32 Amphion website http//www.amphion.com 33
Ligos Corporation website http//www.ligos.com 3
4 LifeSize website http//www.lifesize.com 35
Broadcom website http//www.broadcom.com 36
Netvideo website http//www.netvideo.com 37
Motorola website http//www.motorola.com 38
http//www.mediaware.com 39 Impact Labs Inc.
website http//www.impactlabs.com 40 Vanguard
Software Solutions website http//www.vsofts.com
41 STMicroelectronics website http//us.st.com
www.thomson.net 42 www.conexant.com (H.264
decoder ICs _ HDTV SDTV) 43 www.pixtree.com
85
44 BT Exact--http//www.btexact.bt.com/ 45
DemoGaFrX--www.dolby.com 46 Equator--http//www.
equator.com/ 47 Moonlight--www.elecard.com 48
Sand Video--www.broadcom.com/ 49
VideoLocus-http//www.lsilogic.com/technologies/in
dustry_standards/mpeg_based_standards_h_264.html
50 WW Communications (and DSP
Research)--http//www.wwcoms.com/ 51 Cisco
Systems -- www.cisco.com 52 Deutsche Telekom--
http//www.telekom3.de/en-p/home/cc-startseite.htm
l
86

• 53 FastVDO-- http//www.fastvdo.com/
• 54 Glance Networks---http//www.glance.net
• 55 RADVISION-- www.radvision.com/
• 56 Sun Microsystems--http//www.sun.com/
• 57 S. Srinivasan et al, Windows media video
  9 Overview and applications, Signal Processing
  Image Communication, vol.19, pp. 851-875, Oct.
  2004.
• 57a G. Sullivan and T. Wiegand, Video
  compression from concepts to H.264/AVC
  standard, Proc. IEEE, vol.93, pp. 18-31, Jan.
  2005.
• 57b C. Gomila, The H. 264/MPEG -4 AVC video
  coding standard, Short tutorial, EURASIP News
  Letter, vol. 15, pp. 19-34, June 2004.
• 58 http//ecs.itu.ch

87

• 59 N. Kamaci and Y. Altunbasak, Performance
  comparison of the emerging H.264 video coding
  standard with the existing standards, IEEE ICME,
  pp. , Baltimore, MD, July 2003.
• 60 H. Schwartz, D. Marpe and T. Wiegand,
  SNRscalable extension of H.264/AVC, ICIP 2004,
  vol. , pp. , Singapore, Oct. 2004.
• 61 G. J. Sullivan, P. Topiwala and A. Luthra
  The H.264/AVC advanced video coding standard
  Overview and introduction to the fidelity range
  extensions, SPIE Conf. on applications of
  digital image processing XXVII, vol. 5558, pp.
  53-74, Aug. 2004.
• 62 J. Ostermann et al, Video coding with
  H.264/AVC Tools, performance and complexity,
  IEEE CAS Magazine, vol. pp.7-34, I quarter,
  2004.
• 63 W. Gao et al, AVS The Chinese
  next-generation video coding standard, NAB 2004,
  Las Vegas, NV, April 2004.
• 64 http//www.imtc.org/activity_groups/
  JVT-EXPERTS LIST (FAQ)

88

• 65 H.264 / AVC reference SOFWARE 9.3
• 66 http//iphome.hhi.de/suehring/tml/download/jm
  93.zip
• 67 S. Kumar et al Overview of error resiliency
  schemes in H.264/AVC standard, JVCIR, Special
  Issue on H.264/AVC, VOL. , pp. , June-Aug. 2005.
• 68 www.stmicroelectronics.com WMV 9 and HD
  H.264/AVC decoder chip (STB7100)
• 69 a. Concept Main
• http//www.mainconcept.com/index_flash.shtml
• b. Mpegable
• http//www.mpegable.com/show/home.html
• c. Moonlight
• http//www.moonlight.co.il/cons_xmuxer.php
• Moonlights codec is one of the popular ones in
  the industry and it supports AAC. All the codecs
  have a trial version for download and also sample
  video clips are available.

89

• 70 ST Thomson, Broadcom and Ateme
• http//www.ateme.com/products/h264.php
• have decoder chips for H.264. Ateme has real
  time single chip H.264 Main profile encoder
  (FPGA)
• 71 Moscow State University has published a
  study of current implementation of H.264
  standard, including a widely-used implementation
  of MPEG-4 ASP as a reference.
• The study is available at
• http//compression.ru/video/codec_comparison/mpe
  g-4_avc_h264_en.html
• Some of the results and observations in the
  study may be interesting to H.264/AVC community.
• Another interesting test has been performed in
  December 2004.
• http//www.doom9.org/codecs-104-1.htm The
  methodology is completely different than the one
  used by the Moscow State University.
• It features H264, WM9, RV10, VP6 and MPEG-4 ASP.

90

• http//www.avc-alliance.org
• http//ftp3.itu.int/av-arch/jvt-site
• Http//www.dvdforum.org/29cmtg-resolution.htm\
• High Profile is now officially mandatory for HD
  DVD Video (DVD - Forum).
• http//tinyurl.com/3u9ww (up to 3 recommendations
  can be downloaded per year)
• http//tinyurl.com/6dnck (ISO/IEC 14493-10 -
  MPEG-4 part 10 published standard costs CHF
  260.00 Swiss Franks.)

91
Fidelity Range Extensions

• Slices in a picture are compressed as follows
• ? "Intra" spatial (block based) prediction
• o Full-macroblock luma or chroma prediction 4
  modes (directions) for prediction
• o 8x8 (FRExt-only) or 4x4 luma prediction 9
  modes (directions) for prediction
• 422, 444 Formats
• gt 8 bit depths
• (8x8) integer DCT
• HVS weighting matrices
• Transform bypass lossless mode uses prediction
  and entropy coding of prediction errors
• Residual color transform
• Source editing such as Alpha blending
• High bit rates use RGB color format Y Cg Co
• High resolution

92

• ? "Inter" temporal prediction block based
  motion estimation and compensation
• o Multiple reference pictures
• o Reference B pictures
• o Arbitrary referencing order
• o Variable block sizes for motion compensation
• Seven block sizes
• 16x16, 16x8, 8x16, 8x8, 8x4, 4x8 4x4
• o 1/4-sample luma interpolation (1/4 or
  1/8th-sample chroma interpolation)
• o Weighted prediction
• o Frame or Field based motion estimation for
  interlaced scanned video

93
? Interlaced coding features o Frame-field
adaptation Picture Adaptive Frame Field
(PicAFF) Choice of compression (frame or field)
is selected a the frame level MacroBlock
Adaptive Frame Field (MBAFF) o Field scan ?
Lossless representation capability o Intra PCM
raw sample-value macroblocks o Entropy-coded
transform-bypass lossless macroblocks
(FRExt-only) In the MBAFF, choice of compression
(frame or field) is selected at the
two-vertical-pair-MB pair.
94
? 8x8 (FRExt-only) or 4x4 Integer Inverse
Transform (conceptually similar to the well-known
DCT) ? Residual color transform for efficient
RGB coding without conversion loss or bit
expansion (FRExt-only) ? Scalar quantization ?
Encoder-specified perceptually weighted
quantization scaling matrices (FRExt-only) ?
Logarithmic control of quantization step size as
a function of quantization control parameter
95

• ? Deblocking filter (within the motion
  compensation loop)
• ? Coefficient scanning
• o Zig-Zag (Frame)
• o Field (alternate scan)
• ? Lossless Entropy coding
• o Universal Variable Length Coding (UVLC) using
  Exp-Golomb codes
• o Context Adaptive VLC (CAVLC)
• o Context-based Adaptive Binary Arithmetic
  Coding (CABAC)

96

• ? Error Resilience Tools
• o Flexible Macroblock Ordering (FMO)
• o Arbitrary Slice Order (ASO)
• o Redundant Slices
• ? SP and SI synchronization pictures for
  streaming and other uses

97

• ? Various color spaces supported (YCbCr of
  various types, YCgCo, RGB, etc. especially in
  FRExt)
• ? 420, 422 (FRExt-only), and 444
  (FRExt-only) color formats
• ? Auxiliary pictures for alpha blending
  (FRExt-only)
• Each slice need not use all these tools.
  Depending upon the subset of these tools, a slice
  can be I, P, B, SP or SI. A picture may contain
  different slice types.

98
Slice I (Intra) P (Predicted) B
(Bidirectionally predicted) (Reference for
temporal prediction or non-reference) SP
(Switching P) SI (Switching I)
99
I Slice (MB in I slice and intra MB in P and B
slices) Spatial intra prediction 9 directional
modes for (4x4) or (8x8) blocks. Apply (4 x4)
or (8x8) IntDCT to Intra prediction errors.
Note (8x8) IntDCT for FRExt-only. After
(8x8) IntDCT, HVS weighting is applied to
coefficients (FRExt-only).
100
Quantized transform coefficients are scanned
(zigzag or field) and then entropy coded (CAVLC
or CABAC) PICAFF Field processing similar to
frame mode MBAFF If MB pair in field mode
(frame mode), field (frame) neighbors are
used for spatial prediction.
101

• I Slice (Spatial Prediction)
• (16x16) Luma Corresponding chroma block size
  for full MB prediction
• (8x8) luma prediction (FRExt-only)
• (4x4) Luma prediction

102

• For (16x16) luma, full MB prediction has four
  modes
• Vertical pels in MB predicted from pels just
  above of MB
• Horizontal pels in MB predicted from pels just
  left of MB
• DC pels in MB are predicted as average value of
  the neighboring pels
• Planar Prediction
• Assume MB covers diagonally increasing luma
  values.
• Predictor is formed based upon the planar
  equation.

103

• Chroma spatial prediction (operates on entire MB)
• 420 (8x8) Similar to (16x16) Luma MB
  prediction
• 422 (8x16) Vertical, Horizontal, DC,
  Planar
• 444 (16x16)

104
FRExt Only
For (8x8) luma intra prediction Nine Intra_8x8
prediction modes similar to the nine modes for
Intra_4x4
105
FRExt Only
Integer 8x8 Transform (luma only)
106
FRExt Only HVS Weighting Matrices
107
HVS Weighting Matrices

• Scaling matrix reflecting visual perception is
  simply a multiplier applied during the inverse
  quantization. (This itself is a multiplication)
• Weighting matrices can be customized separately
  for
• 4x4 Intra Y
• 4x4 Intra Cb, Cr
• 4x4 Inter Y
• 4x4 Inter Cb, Cr
• 8x8 Intra Y
• 8x8 Inter Y

108
FRExt Only

• Two scans similar to 4x4 transform switched for
  frame/field coding
• Coefficient scanning is based on the decreasing
  variances and to maximize number of zero-valued
  coefficients along the scan

Frame Zig-Zag
Field
109
Examples of parameters to be encoded

• Parameters Description
• Sequence, picture and Headers and parameters
• slice-layer syntax elements
• Macroblock type mb_type Prediction method for
  each coded macroblock
• Coded block pattern Indicates which blocks
  within a macroblock contain coded
  coefficients
• Quantiser parameter Transmitted as a delta value
  from the previous value of QP
• Reference frame index Identify reference
  frame(s) for inter prediction
• Motion vector Transmitted as a difference (mvd)
  from predicted motion vector
• Residual data Coefficient data for each 4x4 or
  2x2 block

110
Exponential Golomb Codes (for data elements other
than transform coefficients these codes are
actually fixed, and are also called Universal
Variable Length Codes (UVLC))
111

• These are variable length codes with a regular
  construction
• M Zeros 1 INFO
• INFO is an M-bit field carrying information.
• The first codeword has no leading zero or
  trailing INFO.
• Code words 1 and 2 have a single-bit INFO field,
  code words 3-6 have a two-bit INFO field and so
  on.