1
OBJECT-BASED VIDEO CODING
USING A DYNAMIC CODING SCHEME
Marc CHAUMONT
1, Stéphane PATEUX
2, Henri NICOLAS
33
IRISA, 35042 Rennes, FRANCE
2
FT R&D, 35512 Cesson-Sévigné, FRANCE
1
LIUPPA, 64013 Pau, FRANCE
CONTEXT :
Video object coding
SOLUTION :
A Global scheme with 4 video object coders (Dynamic Coding) Definition of a common distortion metric
A rate distortion optimization OBJECTIVE :
Demonstrate the competitivity of
Object Coding versus Non Object coding
SLIDE 2 SLIDE 4 SLIDE 4
2
OUR DYNAMIC CODING SCHEME
[ITU-T Rec. H.264 / ISO/IEC 11496-10, 02]
JM5
[Galpin et al. 01]
[Balter et al. 03]
[Cammas et al. 03]
[Marquant 00]
[Pateux et al. 01]
3
STATE-OF-THE ART CODERS
a 3D mesh a texture
+ camera motions
a sprite image
+ parametric motions
a 2D mesh projected textures Bloc motion Bloc textures
3D model-based coder Sprite coder
t+2D wavelet coder
for GOP 0-8H264/AVC object based coder
for GOP 108-119 for GOP 0-90
for image 3
4
RESOLUTION BY LAGRANGIAN FORMULATION : OBJECTIVE :
A COMMON RATE-DISTORTION METRIC
A RATE-DISTORTION OPTIMIZATION
motion projected
texture
coded-decoded motion
projected texture
MSEtext
MSEtext
MSEtext
projected textures coded-decoded Sprite
WLT 3D
m3dcoder
objects
H264/AVC MSEtext MSE
coders
5
13
80 147
109
RESULTS foreman CIF 15Hz
dynamic coding
rate = 99 Kb/s*
PSNRtext = 33.4 dB
H264/AVC coding rate = 100 Kb/s
PSNRtext = 32.9 dB
dynamic coding
rate = 262 Kb/s*
PSNRtext = 36.2 dB
H264/AVC coding rate = 268 Kb/s
PSNRtext = 37.6 dB
R
constraint= 93Kb/s
R
constraint= 256Kb/s
* lossy shape coding : 6 kb/s [chaumont et al. 03]
Background wlt3D
FaceH264/AVC 109 Kb/s
147 Kb/s Background sprite
FaceH264/AVC 13 Kb/s
80 Kb/s
6
RESULTS & CONCLUSION
H264/AVC coding rate = 105 Kb/s
PSNRtext = 26.7 dB dynamic coding
rate = 100 Kb/s*
PSNRtext = 27.2 dB
player : 70 Kb/s (H264/AVC)
background : 25 Kb/s (sprite+affine motion) shape : 5 kb/s
*
CONCLUSION :
A clever rate repartition
A clever coding of each object
Better than H264/AVC at low bit-rate (<256Kb/s, CIF 15Hz) A positive item for object coding approaches
PERSPECTIVES :
Replace time computational consuming step (curves’ extraction & RD optimization) by a simple prediction step.
Use other metrics close to Human Visual System
m3dcoder coding rate = 100 Kb/s
PSNRtext = 31.3 dB
H264/AVC coding rate= 113 Kb/s
PSNRtext = 28.3 dB
Stefan 352x240 15Hz Thabor Stairs CIF 25 Hz
