A Novel Rate Control Method for H.264/AVC Based on Frame Complexity and Importance - Advanced Concepts for Intelligent Vision Systems - page 75

(a) PSNR fluctuation of moniter (b) PSNR fluctuation of salesman

(c) PSNR fluctuation of akiyo (d) PSNR fluctuation of mumdaughter

Fig. 3. PSNR fluctuation comparison between the proposed method and JVT-G012

curve is given in Fig. 2, with Bjontegaard delta PSNR (BDPSNR) [14] comparing the
difference between two RD curves.
From Fig.2, it is clear that the proposed method has a better coding efficiency,
especially in middle bandwidth. The BDPSNR of the proposed method is improved by
up to 0.541 dB for moniter, the minimum improvement is 0.248dB for sales-
man, a sequence with normal motion and less scene change sequence. Additional
comparisons are given in Table 2, where PSNR standard deviation,

1

n

∑

2

PSNRσ= ( PSNR − PSNR ) , is used to describe PSNR fluctuation. Standard

i

n − 1

i = 1

deviation is a parameter to measure numerical value spread out degree in mathematics.
In Table 2, it is clear that the PSNR standard deviation, PSNRσ, of the proposed
method decreases from 0.134dB to 1.514dB compared to JVT-G012, it implies that
the rate-control accuracy of the proposed method is better that of JVT-G012. Clearer
results are listed in figure show the PSNR fluctuation under the condition as target bit