Rate control in heterogeneous transcoder

This paper introduces an adaptive rate control algorithm in the heterogeneous video transcoding. First, quite a few I-frames which occupy many bits in pre-encoded MPEG-2 video stream be considered. Perceptual redundancies can be removed from I-frame. if we utilize psychovisual properties of the human visual system (HVS). Second, the course of transcoding can be completed by DCT coefficients requantized. We substitute a bit estimation model in the frequency domain for the model in the spatial domain, which needn´t IDCT and DCT. Experimental results show that the proposed algorithm improves transcoding efficiency and image quantity.