[M4IF Technotes] Coder efficiency

[Yang, Wei Jian (Mac)]

Dear MPEG4 experts:
When I use Momusys as reference MPEG4 codec, I find that something
interesting.
This DCT-like coder has much better efficiency than MPEG2
Simulating environment is:
1. MPEG2 coder: 1996, MPEG Software Simulation Group, MP   ML
2. MPEG4 coder: MoMuSys-FDIS-V1.0-990812 simple profile
3. Akiyo.yuv
4. 96000kbps, MPEG2 TM5 Rate Control
Compare result is: (bits/PSNR-Y(db))
	    I		P	B	 ......
MPEG2	37740/32         7234/32.6   9979/33.1
MPEG4	47982/37.8      678/37.5     80/37.7
I find that MPEG2 coder produce much more MVs in P and B than those in
MPEG4.
I guess in MPEG4, it uses a more efficient MB type decision policy in Motion
Estimation.
I know MPEG4 adopts quarter-pixel prediction, but does it has such high
impact on
ME efficiency? 
Any comments?
Thanks
Mac
Yang, Wei Jian (Mac)
Bell labs, Shanghai
Lucent Technologies (China) Co., Ltd.
Tel:         8621-5450-4555  ext. 8610
Fax:        8621-5490-2106
E-mail:   yangwj   lucent.com