Submitted by Keyur Shah 1000658106 keyurshahmavsutaedu Under guidance of Dr KRRao Motivation H264 is the most widelyaccepted video standard and has spawned a huge amount of software that implements it viz JM X264 and ID: 663598
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Slide1
Implementation, Performance Analysis & Comparison of H.264 and VP8
Submitted by:
Keyur
Shah (1000658106)
keyur.shah@mavs.uta.edu
Under guidance of Dr.
K.R.RaoSlide2
Motivation:
H.264 is the most widely-accepted video standard
and
has spawned a huge amount of software that implements it viz., JM, X264 and
Ffmpeg
.
[3]
H.264 is used in various
applications like video broadcasting, video streaming, video
conferencing, HDTV, Blu-ray Discs.
VP8
is an open video compression format released by
Google
, originally developed by
On2 Technologies
.[25]
VP8
offers significant gains in compression
performance.
VP8
is less compute intensive to
decode. [8]
VP8
is used as the codec for HTML5, video playback in Internet Explorer 9, Mozilla, Opera
and
Google Chrome. Adobe Flash Player also supports VP8 playback
. [17]Slide3
Goal of the Project (Comparison of VP8 and H.264):
Feature
(parametric
)
comparison
:
Prediction schemes
Transform
In-loop filter
Entropy
coding
Performance
comparison
:
1) Bit
rate
2) PSNR
3) MSE
4)
SSIM [26]
5) Compression
ratio
6) Complexity
(encoding time and decoding time)Slide4
Why H.264?
One of the most widely accepted video coding standards.
Block-oriented motion-estimation based codec.
Higher coding efficiency than previous standards, MPEG-1,2,4, H.261 and H.263. [28]
Simple syntax specifications.
Seamless integration of video coding into all current protocols.
More error robustness.Slide5
Profiles of H.264:
Table 1:
H.264 profiles
[3]Slide6
Specific coding schemes of profiles
Fig 1:
H.264 coding profile schemes
[3]Slide7
WHY VP8?:
Inheriting many great innovations from its predecessors (VP7 and VP6) such as golden frames, processor-adaptive real-time encoding and a low-complexity loop filter, VP8 adds more than fifty new techniques to achieve its goal of outstanding quality at low bitrates, with very low complexity
. [6]
VP8 specifies exact values for reconstructed pixels. This greatly facilitates the verification of the correctness of a decoder implementation as well as avoiding difficult-to-predict visual incongruities between such implementations. [6
]
VP8 offers both VBR (variable bitrate) and CBR (constant bitrate) encoding options
.
CBR attempts to keep the bitrate more
constant,
i.e. the
codec tries to remain within given buffering
constraints.
If the user sets CBR mode but gives very loose buffer restrictions, then the result will start to resemble VBR.Slide8
VP8
has been designed with a wide range of machines in mind, from 60 MHz ARM9 processors to today's highly parallel multi-core processors. It encodes in real-time on low-end
machines
and takes fewer cycles to decode than other leading algorithms. [8
]
Fig 2: Parallel processing in VP8. [8]Slide9
Fig. 3: H.264 encoder block diagram. [3]Slide10Slide11
Fig. 5: H.264 decoder block diagram. [3]Slide12
Parametric Comparison (VP8 and H.264):
Intra Prediction:
Intra prediction is used to guess the content of a block without referring to
other
frames
.
H.264 has three
Intra-Prediction modes
[3]
1
) 4x4
luma
prediction
modes
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)
Fig 6: 4x4
luma
prediction modes. [3]
2
) 16x16
luma
prediction modes :
4 prediction modes (vertical : 0, horizontal : 1, DC : 2, plane : 3) 3) 8x8 chroma prediction mode: Similar to 4x4 luma with low pass filtering of the predictor to improve prediction performance.
a
b
c
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B
C
D
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mode 1
mode 6
mode 0
mode 5
mode 4
a
b
c
d
e
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H
mode 8
mode 3
mode 7Slide13
VP8
has
four
Intra-Prediction modes [22
]
1) H_PRED (horizontal prediction): Fills each column of the block with a copy of the left column,
L
.
2) V_PRED (vertical prediction):
Fills each row of the block with a copy of the above row,
A
.
3) DC_PRED (DC prediction): Fills the block with a single value using the average of the pixels in the row above
A
and the column to the left of
L.
4)
TM_PRED (
TrueMotion
prediction): A mode that gets its name from a compression technique developed by On2 Technologies. In addition to the row
A
and column
L
, TM_PRED uses the pixel
C
above and to the left of the block. Horizontal differences between pixels in
A
(starting from C) are propagated using the pixels from L to start each row.
Fig 7: VP8 intra prediction modes. [22]Slide14
2
) Inter Prediction:
Inter prediction is used to guess the content of a block by referring to
past and/or future
frames
.
There are two primary components to inter prediction: reference frames and motion vectors. The reference frame is a past frame from which to grab pixels from and the motion vectors index an offset into that frame
.
H.264 has three frames:
I-frames, P-frames and
B-frames [3]
1) The
first image in a video sequence is always an
I-frame.
2) A
P-frame, which stands for predictive inter
frame.
3) A
B-frame, or bi-predictive inter
frame. [6]
VP8 has two frames common with H.264, I-frames and P-frame but B-frames are missing here, instead there are
altref
frames (alternative reference).
VP8 also has
alternate prediction frames, called
golden
frames.Slide15
3) Transform and Quantization:
A
) Transform [7]
The general method for transformation in both H.264 and VP8 is the same, each
16×16
macroblock
is divided into
sixteen 4×4
DCT blocks, each of which is transformed by a bit-exact DCT approximation.
The main difference is that in VP8,
DC coefficients of these
bit-exact DCT blocks are
collected into another 4×4 group, which
are
then
Walsh-
Hadamard
transformed. [27]
B) Quantization [7]
The general method here also remains the same but there is a small difference again, H.264 has a built-in
macroblock
-level
quantizer
(adaptive quantization) whereas VP8 does not have it.
Slide16
4) Entropy Coding: Entropy
coding is the process of taking all the information from all the other processes: DCT coefficients, prediction modes, motion vectors, and so forth — and compressing them
lossless
into the final output file
.
VP8 and H.264 use an arithmetic coder for this purpose.
The difference is H.264 uses an adaptive arithmetic coder whereas VP8 uses non-adaptive arithmetic coder. [7]
5) Loop Filter: The
loop filter is run after decoding or encoding a frame and serves to perform extra processing on a frame, usually to remove
blockiness
in DCT-based video formats
.
They have same kind of loop filter with two small differences,
1) VP8 has two modes in loop filtering:
a
simple
mode and a normal
mode.
2)
VP8
filter has wider range
when filtering between
macroblocks
as compared to the H.264 filter. [7]Slide17
Implementation of the Project(Comparison of Parameters for VP8 and H.264):
Performance Comparison:
1) Bit Rate
2) PSNR
3) MSE
4) SSIM [21]
5) Compression Ratio
6) Complexity (encoding time and decoding time)Slide18
Test Sequences:
The test sequences that can be used are in QCIF and CIF (formats)
1) CIF
2) QCIF
Fig(a) : Common Intermediate Format(CIF) 4:2:0
chroma
sampling. [3]
Fig (b): Quadrature Common Intermediate Format (QCIF) 4:2:0
chroma
sampling. [3]Slide19
Software that can be used:
1)
Softwares
for H.264:
f
fmpeg
:
Fast Forwarding
Mpeg, version
0.6.1
. [18]
f
fmpeg
is a free software / open source project that produces libraries and programs for handling multimedia data.
[30]
JM Software: Current
version
17.2 [23]
JM software is the most widely used software for testing H.264/10 AVC.
2)
Softwares
for VP8:
libvpx
:
The VP8
codec SDK, version 0.9.0-5. [6]
l
ibvpx
is a free software/ open source project developed by On2 Technologies to test VP8 codec.
f
fvp8:
ffmpeg
team’s own VP8 decoder, version 0.6.1. [18], [31]
ffvp8 is a free software/ open source project. It is ffmpeg software itself but the latest version (mentioned above) has included libvpx libraries (encoder and decoder). [30], [31]Slide20
REFERENCES:
[1] T.
Wiegand
and G. J. Sullivan, “The H.264 video coding standard”, IEEE Signal Processing Magazine, vol. 24, pp. 148-153, Mar. 2007.
[2] D.
Marpe
, T.
Wiegand
and G. J. Sullivan, “The H.264/MPEG-4 AVC standard and its applications”, IEEE Communications Magazine, vol. 44, pp. 134-143, Aug. 2006.
[3] S. K. Kwon, A.
Tamhankar
and K. R.
Rao
, “Overview of H.264/MPEG-4 Part 10” J. Visual Communication and Image Representation, vol. 17, pp.186-216, Apr. 2006.
[4] A.
Puri
, X. Chen and A.
Luthra
, “Video coding using the H.264/MPEG-4 AVC compression standard”, Signal Processing: Image Communication, vol. 19, pp. 793-849, Oct. 2004.
[5]
http://www-ee.uta.edu/Dip/Courses/EE5359/
Thesis%20Project%20table%20docs/Padiathesis
.
pdf
–
“Complexity reduction for VP6 to H.264 transcoder using motion vector reuse”, M.S. Thesis, EE Dept., UTA, May2010.
[6] VP8 Data Format and Decoding Guide
WebM
Project
Google On2,
http://www.webmproject.org/Slide21
[7] http://x264dev.multimedia.cx/archives/377-
The first in-depth technical analysis of VP8.
[8]
http://
www.eetimes.com/design/signal-processing-dsp/4017748/The-VP8-video-codec-High-compression-low-complexity-
EE Times Design: The VP8 video codec: High compression + low complexity.
[9] G. J. Sullivan, “ The H.264/MPEG-4 AVC video coding standard and its
deployment status”, SPIE/VCIP 2005, vol.5960, pp.709-719, Beijing, China, July 2005.
[10]
K.
Onthriar
, K. K. Loo and Z.
Xue
, “Performance comparison of emerging Dirac video codec with H.264/AVC”, IEEE International Conference on Digital Telecommunications, vol. 06, page: 22, issue: 29-31, Aug. 2006.
[11]
http
://
trace.eas.asu.edu/yuv/index.html
- Video test
sequences
(
YUV 4:2:0
)
[12]
http://iphome.hhi.de/suehring/tml/
- JM software source code
[13]
I.E.Richardson
, “
The H.264 Advanced Video Compression Standard”,
2
nd
Edition, Wiley, 2010.Slide22
[14] http://www.webmproject.org/code/repository-layout/
- VP8 Video Codec Library.
[15]
http://www.webmproject.org/code/
- Explore the
WebM
Source Code for VP8.
[16]
http://multimedia.cx/eggs/vp8-the-savior-codec/
-
VP8: The Savior Codec.
[17]
http://en.wikipedia.org/wiki/VP8
- General VP8 information.
[18]
http://www.ffmpeg.org/
-
FFmpeg
software.
[19]
http://en.wikipedia.org/wiki/HTML_5
- General HTML5 information.
[20]
https://ece.uwaterloo.ca/~z70wang/research/ssim
/
-
The SSIM Index for Image Quality
Assessment.
[21]
http://multimedia.cx/eggs/vp8-transform-and-quantization
/
- VP8 encoder and decoder explanation.[22] http://blog.webmproject.org/search/label/vp8#uds-search-results - Inside WebM Technology: VP8 Intra and Inter Prediction.[23] http://iphome.hhi.de/suehring/tml/ - JM Software Download.[24] http://iphome.hhi.de/suehring/tml/JM%20Reference%20Software % 20Manual%20(JVT-AE010).pdf – JM Software Installation Guide.[25] www.on2.com – On2 Technologies (VP8 developers). Slide23
[26] Z. Wang
, et al,
“Image Quality Assessment: From Error Visibility
to Structural Similarity”,
IEEE
Transactions on Image Processing, vol.
13,
no.
4,
Apr. 2004.
[27]
http://
en.wikipedia.org/wiki/Hadamard_transform
- General information on Walsh
Hadamard
Transform.
[28]
http://www.stanford.edu/class/ee398b/handouts/lectures
/ 03-StandardsH261H263.pdf
– H.261 and H.263 overview.
[29]
http://hawkeye.arrozcru.org
/
- Latest
ffmeg
software for win32 and win64.
[30]
http://
x264dev.multimedia.cx/archives/499
- ffvp8 and
libvpx
comparison.