Patent ID: 7170933

Claim:
A method for measuring the video quality of a coded frame of a compressed video stream without access to an original or reference video source and while utilizing only the information embedded in the compressed video stream, comprising: estimating quantization errors of the coded frame of the compressed video stream; estimating blocking effects of the coded frame of the compressed video stream; and measuring the video quality of the coded frame of the compressed video stream by adaptively combining the estimate of quantization errors with the estimate of blocking effects and with motion information on the coded frame of the compressed video stream; wherein: the compressed video stream comprises an MPEG video stream consisting of a sequence of coded frames; an input MPEG video bitstream is partially decoded by an MPEG decoder to obtain (1) inverse quantized DCT coefficients, (2) quantization scale and (3) motion vectors for each frame; and the step of estimating quantization errors includes the step of estimating a probability distribution of the inverse quantized DCT coefficients by applying histogram statistics to the inverse quantized DCT coefficients to derive a histogram, which is then used to estimate a distribution on a piece-wise basis.