Video Compression Standards : A
Comparative Analysis of H.264, Dirac
and AVS P2
By Sudeep Gangavati
ID 1000717165
EE5359 Spring 2012,
UT Arlington
Objective and motivation
• The goal – to compare H.264/AVC, AVS P2 and Dirac
• Video quality assessment – MSE, PSNR, SSIM
• Ever increasing demand for video compression
• Several different video coding standards have
been developed to address the needs efficient
video coding for multitude of applications like
video streaming, TV broadcasting, 3D TV, Freeviewpoint TV etc. [24].
H.264/AVC Features
• The most widely used video coding standard
Fig. 1 Video coding standards evolution [12]
Features
• Motion compensated coding structure
• Picture  slices  MBs  subMBs  blocks
 pixels. This is shown in Figure 3.
• Only 4:2:0 chroma format was supported
earlier and 4:2:2 , 4:4:4 were added later. This
is shown in Figure 2.
• I , P and B slices
• Derived slices SI and SP
Fig 2. 4:4:4, 4:2:2, 4:2:0 sampling patterns
Fig 3. H.264 syntax
Profiles and levels
•
•
•
•
Main Profile
Baseline Profile
Extended Profile
High Profile
H.264 Profiles
Fig.4 H.264 profiles [1]
H.264 Encoder
Fig. 5 Encoder structure for H.264 [2]
H.264 Decoder
Fig.6 Decoder structure of H.264 [2]
Intra and Inter Predictions
Intra Prediction :
•
•
•
•
Uses spatial prediction to reduce spatial redundancy.
4 X 4 luma – 9 modes
16 X 16 luma – 4 modes
8 X 8 luma- 9 modes
Intra prediction modes for 4X4 luma
Fig.7(a) Intra prediction modes [6]
The samples above and to the left, labelled A-M in Figure 7 have previously
been encoded and reconstructed and are therefore available in the encoder
and decoder to form a prediction reference.
Intra Prediction Modes for 16x16 luma
• Again the previously encoded samples directly above
and to the left of the macroblock have been
reconstructed and are used for the prediction
Fig 7 (b) Intra prediction modes for 16x16 luma [6]
Inter prediction
 Uses motion estimation and motion compensation
(MC).
1 macroblock partition of
16*16 luma samples and
associated chroma samples
Macroblock
partitions
2 macroblock partitions of
16*8 luma samples and
associated chroma samples
2 macroblock partitions of
8*16 luma samples and
associated chroma samples
0
0
0
Sub-macroblock
partitions
2 sub-macroblock partitions
of 8*4 luma samples and
associated chroma samples
2 sub-macroblock partitions
of 4*8 luma samples and
associated chroma samples
0
0
0
0
1
2
3
1
1
1 sub-macroblock partition
of 8*8 luma samples and
associated chroma samples
4 sub-macroblocks of
8*8 luma samples and
associated chroma samples
4 sub-macroblock partitions
of 4*4 luma samples and
associated chroma samples
0
1
2
3
1
1
Fig.8 H.264 Inter prediction [5]
De-blocking filter[5]
• Is used to reduce the blocking artifacts.
• Since the filter is present in the loop , it prevents the propagation of the
blocking artifacts.
Fig. 9 Boundaries in a macroblock to be filtered (luma boundaries shown with solid lines
and chroma boundaries shown with dotted lines) [1]
AVS China[7]
• AVS-Audio Video Standard
• Standardization includes system, audio, video
and digital copyright management.
• Goal – to achieve coding efficiency with
reduced complexity.
AVS Parts [3]
Fig. 10 AVS China parts [3]
AVS P2 Encoder [7]
Fig. 11 AVS part 2 encoder [7]
AVS P2 decoder
Fig 11 (a) AVS P2 decoder block diagram [7]
Intra Prediction in AVS[7]
• Spatial prediction is used in intra coding in AVS
part 2.
• The Intra prediction is based on 8x8 block
• The intra prediction method is derived from
the neighboring pixels in left and top blocks
Intra Prediction contd.
Fig.12 (a) Five different modes for intra luminance prediction[16]
Inter prediction [16]
• Inter prediction in AVS is by motion compensation
and motion estimation [16].
• As shown in the Figure 12 (b), the macroblock can
have 16 x 16, 8 x 16, 16 x 8 or 8 x 8 [16].
Fig 12 (b) Macroblock sizes [16]
Dirac
• Dirac is a video codec originally developed by
BBC
• This technique is used from web streaming of
videos to HD TV applications to storage of
content.
• Dirac can compress any resolution picture
• The encoder and decoder diagrams are shown
in Figure 13 (a) and (b) respectively.
Dirac encoder and decoder :
Figure 13 (a) Dirac encoder[8]
Figure 13 (b) Dirac decoder[8]
Dirac pro Features
Dirac pro supports the following technical aspects [9]:
•
•
•
•
•
•
•
Intra-frame coding only
10 bit 4:2:2
No subsampling
Lossless or visually lossless compression
Low latency on encode/decode
Support for multiple HD image formats and frame rates
Low complexity for decoding
Experimental Results
Implementation of DIRAC Software 1.02:
Video sequence: news_qcif.yuv.
Width: 176, Height: 144.
Total number of frames: 300
Number of frames used for encoding: 100.
Frame rate: 25 FPS. File Size: 3713kB.
Quality
Factor
Compressed
File Size
Bit rate
(kBps)
Y-PSNR(dB)
Y-MSE
Y-SSIM
Comrpession
Ratio
0
38
9.573
25.773
187.13
0.79
98:1
5
61
15.571
32.134
39.588
0.95
60:1
10
369
96.301
46.699
1.41
0.98
10:1
15
1278
130.12
51.799
0.743
0.99
2.9:1
Table 1: Parametric values for Dirac video codec
Experimental Results contd.
Quality
Factor = 5
Quality
Factor = 0
Quality
Factor = 10
Fig.14 Output of Dirac video codec at different Quality Factors
Video sequence: foreman_qcif.yuv
Width: 176; Height: 144.
Total number of frames: 300
Number of frames used for encoding: 100.
Frame rate: 25 FPS; File Size: 3713kB
Quality
Factor (QF)
Compressed
File Size (kB)
Bitrate
(kBps)
Y-PSNR (dB)
Y-MSE
Y-SSIM
Compressio
n Ratio
0
27
8.991
21.5
301.56
0.6875
138:1
5
58
12.675
28.91
110.12
0.8613
64:1
10
581
140.673
43.675
0.827
0.979
6:1
15
1340
170.342
49.556
0.667
0.99
2.7:1
Table 2. Parametric values of Dirac video codec for foreman_qcif video
•
QF=0
QF=05
QF=10
QF=15
Fig.15 Output of Dirac video codec at different Quality Factors for foreman_qcif video
Implementation of AVS software
Video sequence used: news_qcif.yuv
Width: 176;Height: 144
Total number of frames: 300; Number of frames used: 100
Frame rate: 25 FPS; File Size: 3713kB
QP=0
QP=10
QP=50
Fig.16 Output of AVS video codec at different Quality Factors for news_qcif video
Fig.17 Output of AVS video codec at different Quality Factors for foreman _qcif video
Implementation of AVS software
Quantization
Parameter (QP)
Compressed
File Size
Bit rate
(kBps)
Y-PSNR(dB)
Y-MSE
Y-SSIM
Comrpession
Ratio
0
980
554.19
54.773
0.2587
0.9997
3:1
10
442
219.12
49.72
0.5525
0.9945
9:1
30
64.0
156.49
38.49
9.23
0.9760
58:1
50
12.0
29.26
27.96
104.13
0.8506
309.7
Table 3. Parametric values of AVS video codec for news_qcif video
QP
Compressed
file size
Bitrate
Y-PSNR
Y-MSE
Y-SSIM
Compressio
n Ratio
0
1123
478.88
52.658
0.2823
0.998
3:1
10
450
278.9
48.775
0.781
0.9903
8.25:1
30
70
79.66
35.231
13.56
0.867
53:1
50
14
24.5
29.780
146.32
0.776
265:1
Table 4. Parametric values of AVS video codec for foreman_qcif video
Implementation of H.264 software (JM 18.0)
Quantization
Parameter
(QP)
Compressed
File Size
Bit rate
(kBps)
Y-PSNR(dB)
Y-MSE
Y-SSIM
Comrpession
Ratio
0
279
685.19
60.773
0.21619
0.999
13:1
10
208
410.21
48.545
0.9653
0.9947
17.8:1
30
123
155.62
35.721
17.4211
0.8626
30:1
50
35
29.49
28.736
224.23
0.7644
27.5:1
Table 5. Parametric values of H.264 video codec for news_qcif video
Quantization
Parameter
(QP)
Compressed
File Size
Bit rate
(kBps)
Y-PSNR(dB)
Y-MSE
Y-SSIM
Comrpession
Ratio
0
379
485.19
62.773
0.21619
0.999
9:1
10
210
340.21
54.67
0.7769
0.9947
18:1
30
98
155.62
34.721
14.4211
0.8626
39:1
50
25
39.49
27.736
236.23
0.6944
27.5:1
Table 6. Parametric values of H.264 video codec for foreman_qcif video
Plots of PSNR (dB) vs. Bitrate (kBps)
PSNR vs Bitrate
65
60
55
50
P S N R (dB)
45
40
35
H.264
30
AVS
25
Dirac
20
15
10
5
0
0
50
100
150
200
250
300
350
400
450
500
550
600
650
Bitrate (kBps)
Fig18. Plot of PSNR vs. Bitrate for different codecs for news_qcif video
700
750
Plots of PSNR (dB) vs. Bitrate (kBps) contd..
60
55
50
45
P S N R (dB)
40
35
30
H.264
25
AVS
Dirac
20
15
10
5
0
0
50
100
150
200
250
300
350
400
450
500
550
Bitrate (kBps)
Fig 19. Plot of PSNR vs. Bitrate for different codecs for foreman_qcif video
Plots of MSE vs. Bitrate
MSE vs Bitrate
250
200
150
MSE
H.264
AVS
Dirac
100
50
0
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
Bitrate (kBps)
Fig 20. Plot of MSE vs. Bitrate for different codecs for news_qcif video
Plots of MSE vs. Bitrate contd..
MSE vs Bitrate
325
300
275
250
225
200
MSE
Dirac
175
AVS
150
H.264
125
100
75
50
25
0
0
100
200
300
400
Bitrate (kBps)
Fig 21. Plot of MSE vs. Bitrate for different codecs for foreman_qcif video
500
600
Plot of SSIM vs. Bitrate
SSIM vs. Bitrate
1.2
1
SSIM
0.8
H.264
0.6
AVS
Dirac
0.4
0.2
0
0
100
200
300
400
500
600
Bitrate (kBps)
Fig 22. Plot of SSIM vs. Bitrate for different codecs for news_qcif video
700
800
Plot of SSIM vs. Bitrate
SSIM vs. Bitrate
1.2
1
SSIM
0.8
H.264
0.6
AVS
Dirac
0.4
0.2
0
0
100
200
300
400
Bitrate
Fig 23. Plot of SSIM vs. Bitrate for different codecs for foreman_qcif video
500
600
Computational complexity
Computational complexity
1200
Time in seconds
1000
800
H.264
600
AVS
Dirac
400
200
0
Codecs
Fig 24. Plot of time taken by each codec at QP=30 and QF=10
Conclusions
• The plots and tabulations show that with the increase in bitrate, there is
an increase in PSNR and SSIM and reduction in the MSE.
• Therefor from the plots and the tables, it can be concluded that H.264
provides optimum performance with respect to PSNR, MSE and SSIM over
AVS part 2 and Dirac.
• Regarding the computational complexity, H.264 is more complex than the
other two standards viz., AVS part 2 and Dirac. This is due to the fact that
H.264 supports several prediction modes and has varied macroblock sizes
when compared to AVS and Dirac.
References
[1] Soon-kak Kwon, A. Tamhankar and K.R. Rao, “Overview of H.264 / MPEG-4 Part 10 (pp.186-216)”,
Special issue on “ Emerging H.264/AVC video coding standard”, J. Visual Communication and Image
Representation, vol. 17, pp.186-216, April 2006.
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81-84, March 2002.
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Communications and Image Processing, Proc. of SPIE, vol. 5960, pp. 679-690, July 2005.
[8] “ The Dirac web page” :http://www.bbc.co.uk/rd/projects/dirac/intro.shtml
[9] “Dirac Codec Wiki Page ” at http://en.wikipedia.org/wiki/Dirac(codec)
[10]“Dirac Pro web page” at http://www.bbc.co.uk/rd/projects/dirac/diracpro.shtml
[11] “Video on the web “ a http://etill.net/projects/dirac_theora_evaluation/
[12] J.Lou “Advanced video codec optimization techniques”, Doctoral Dissertation, Electrical
Engineering Department, University of Washington, August 2009
References
[13] H.264 AVC JM Software : http://iphome.hhi.de/suehring/tml/
[14] H.264 decoder: http://www.adalta.it/Pages/407/266881_266881.jpg
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Vegas, 2004.
[16] X. Wang et al., “Performance comparison of AVS and H.264/AVC video coding standards” J.
Comput. Sci. & Technol., vol.21, No.3, pp.310-314, May 2006.
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[18] S. Swaminathan and K.R. Rao, “Multiplexing and demultiplexing of AVS CHINA video with AAC
audio,” TELSIKS 2011, Nis, Serbia, 5-8 Oct. 2011.
[19] Dirac Pro Software : http://diracvideo.org/download/
[20] M. Tun, K.K. Loo and J. Cosmas, “Semi-hierarchical motion estimation for the Dirac video codec,”
2008 IEEE International Symposium on Broadband Multimedia Systems and Broadcasting, pp.1–6,
March 31-April 2, 2008.
[21] T. Davies, “The Dirac Algorithm”: http://dirac.sourceforge.net/documentation/algorithm/,
2008.
[22] Dirac video codec – A programmer's guide:
http://dirac.sourceforge.net/documentation/code/programmers_guide/toc.htm
[23] A. Ravi and K.R. Rao, “Performance analysis and comparison of the Dirac video codec with
H.264 / MPEG-4 Part 10 AVC,”IJWMIP, vol.4, pp.635-654, No.4, 2011.
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No.4, April 2012