In this paper, we propose a flexible framework for DCT-based video encoding that yields very good computation performance tradeoffs. Each of the encoding components features a set of parameters that can be used to control its computational complexity and performance. A sequence of optimum parameter sets have been designed to obtain encoders with varying degrees of computational complexity. A computation control mechanism is proposed within the encoding framework to allow the encoding algorithm to adapt to the available computational resources. This will allow the encoder to run in real time on machines with different computing power levels, while also achieving the best possible reproduction quality. The proposed framework was applied to MPEG-2 and H.263 encoding. Our experimental results show that excellent speed-performance tradeoffs as well as accurate computation control can be obtained using the proposed method.

This paper presents a joint rate control mechanism for MPEG-2 encoding of multiple video sequences. Our method does not require pre-processing of the video signals prior to encoding. The joint rate control is implemented at the frame level, requiring the encoders to communicate amongst each other only once per frame. Experimental results show that our joint rate control yields better performance than other existing methods. The results also show that our joint rate control coding improves the picture quality of the complex video sequences by assigning them more bits, and maintains a good balance in picture quality among the sequences.

The significance of the presence of coarse dark granules in the perivitelline space of oocytes has not been studied before. The study included 2288 intact oocytes [2063 in metaphase II (MII), 136 in metaphase I (MI), and 89 in germinal vesicle (GV)] retrieved in 206 intracytoplasmic sperm injection cycles stimulated by a long agonist protocol. The incidence of granules varied with oocyte maturity. It was detected in 34.3% and 4% of the MII and MI oocytes respectively, while none of the GV oocytes contained granules. The woman's age, hormonal values (oestradiol and progesterone), human chorionic gonadotrophin/oocyte retrieval interval, number of oocytes retrieved, and oocyte retrieval/injection interval were not related to the percentage of granular oocytes. Moreover, there was no correlation between the percentage of granular oocytes and the fertilization and cleavage rates, pregnancy outcome, as well as the implantation rate. Patients were divided into three groups according to the total human menopausal gonadotrophin (HMG) dose they received. There was a statistically significant difference between the three groups in the percentage of granular oocytes [17.4 +/- 5.2% versus 26.7 +/- 3.2% versus 45.4 +/- 4.2% in the low-dose (< 30 ampoules), intermediate dose (31-45 ampoules), and high-dose (> 45 ampoules) groups respectively]. We conclude that granularity in the perivitelline space is probably a physiological phenomenon related to the maturational events in oocytes and enhanced by exposure to high dosages of HMG.