A method for determining complexity of a video frame in a live video stream, comprising: obtaining a current video frame to be processed, dividing the current video frame into a specified number of picture blocks; when a frame type of the current video frame is unknown or is recognized not to be an I-frame, calculating an interframe prediction value and an intraframe prediction value of a picture block, determining time complexity of the picture block based on a difference between the interframe prediction value of the picture block and an original pixel value of the picture block and determining space complexity of the picture block based on a difference between the intraframe prediction value of the picture block and the original pixel value of the picture block, and taking the smaller of the time complexity and the space complexity as a complexity of the picture block; when the frame type of the current video frame is recognized to be the I-frame, calculating only the intraframe prediction value of the picture block, determining the space complexity of the picture block based on a difference between the intraframe prediction value of the picture block and the original pixel value of the picture block, and taking the space complexity as the complexity of the picture block; and adding the complexity of each of the picture blocks together to obtain the complexity of the current video frame, wherein the obtained complexity is used for setting a bit rate of the live video stream, wherein determining the time complexity of the picture block includes: performing a discrete cosine transformation on the difference between the interframe prediction value of the picture block and the original pixel value of the picture block and taking a sum of the absolute values of coefficients after the discrete cosine transformation as the time complexity of the picture block; and wherein determining the space complexity of the picture block includes: performing a discrete cosine transformation on the difference between the intraframe prediction value of the picture block and the original pixel value of the picture block and taking a sum of the absolute values of coefficients after the discrete cosine transformation as the space complexity of the picture block. obtaining a current video frame to be processed, dividing the current video frame into a specified number of picture blocks; when a frame type of the current video frame is unknown or is recognized not to be an I-frame, calculating an interframe prediction value and an intraframe prediction value of a picture block, determining time complexity of the picture block based on a difference between the interframe prediction value of the picture block and an original pixel value of the picture block and determining space complexity of the picture block based on a difference between the intraframe prediction value of the picture block and the original pixel value of the picture block, and taking the smaller of the time complexity and the space complexity as a complexity of the picture block; calculating an interframe prediction value and an intraframe prediction value of a picture block, determining time complexity of the picture block based on a difference between the interframe prediction value of the picture block and an original pixel value of the picture block and determining space complexity of the picture block based on a difference between the intraframe prediction value of the picture block and the original pixel value of the picture block, and taking the smaller of the time complexity and the space complexity as a complexity of the picture block; when the frame type of the current video frame is recognized to be the I-frame, calculating only the intraframe prediction value of the picture block, determining the space complexity of the picture block based on a difference between the intraframe prediction value of the picture block and the original pixel value of the picture block, and taking the space complexity as the complexity of the picture block; and calculating only the intraframe prediction value of the picture block, determining the space complexity of the picture block based on a difference between the intraframe prediction value of the picture block and the original pixel value of the picture block, and taking the space complexity as the complexity of the picture block; and adding the complexity of each of the picture blocks together to obtain the complexity of the current video frame, wherein the obtained complexity is used for setting a bit rate of the live video stream, wherein determining the time complexity of the picture block includes: performing a discrete cosine transformation on the difference between the interframe prediction value of the picture block and the original pixel value of the picture block and taking a sum of the absolute values of coefficients after the discrete cosine transformation as the time complexity of the picture block; and wherein determining the space complexity of the picture block includes: performing a discrete cosine transformation on the difference between the intraframe prediction value of the picture block and the original pixel value of the picture block and taking a sum of the absolute values of coefficients after the discrete cosine transformation as the space complexity of the picture block.