Patent ID: 8804820

Claim:
A method of performing rate control in a video transcoding system, comprising the steps of: receiving an input video bitstream including a plurality of video frames encoded in a first coding format; obtaining, at a look-ahead bitstream analyzer, frame coding complexity information for at least some of the plurality of video frames; for each of at least some of the plurality of video frames: decoding the video frame, the video frame including a plurality of macroblocks; obtaining local coding complexity information for each of at least some of the plurality of macroblocks included in the video frame; performing bit allocation for the video frame using at least some of the frame coding complexity information obtained at the look-ahead bitstream analyzer; selecting a quantization parameter (QP) appropriate for the bit allocation using at least the local coding complexity information for the video frame; and using the selected QP, encoding the video frame in a second coding format as one of a predictive frame (P-frame), an intra-coded frame (I-frame), and a bidirectional predictive frame (B-frame); having encoded at least some of the plurality of video frames in the second coding format as P-frames or I-frames, adaptively modifying a B-frame rate between at least one pair of P-frames or I-frames based at least on local coding complexity information obtained for a current video frame included in the plurality of video frames; and providing the plurality of video frames encoded in the second coding format in an output video bitstream.