35results about How to "Guaranteed subjective quality" patented technology

A method and apparatus is provided for implementing quantization in encoding/decoding. Firstly, the quantization on the picture transformed coefficient matrix is performed using a quantization parameter model, that is, the coefficient matrix is modeled as a parameter model represented by only several parameters, in which the parameter model includes two sorts of parameters, frequency band distribution parameters and frequency band weighting parameters. Thus, a quantization matrix conforming to the human vision system can be obtained by controlling the model parameters and the subjective quality of the encoded picture can be easily controlled. Secondly, the method does not need to store or transfer the quantization matrix in the bitstream which help to improve the encoding efficiency. Finally, the quantization on picture transformed coefficients using the method is well adapted to the content information of the picture to be encoded. Therefore, the present invention can improve the subjective quality of the encoded picture.

The invention discloses a visual perceptual coding method based on a multi-domain JND (Just Noticeable Difference) model and relates to video information processing. The method comprises the following steps: respectively calculating a space-domain basic JND threshold value, a luminance masking modulation factor, a contrast masking modulation factor and a time domain masking modulation factor of each transformation coefficient in a DCT (Discrete Cosine Transform) block by utilizing a time-space-domain multi-domain JND model so as to obtain the time-space-domain multi-domain JND threshold value of each transformation coefficient; introducing a block perception-based distortion probability evaluative criteria in the transform coding process, and searching a correction factor of each coefficient relative to the JND threshold value through an adaptive searching algorithm so as to obtain a transformation coefficient suppression value; and finally, subtracting the original transformation coefficient from the most appropriate suppression value obtained through corresponding calculation, and taking the coefficient as a novel coefficient to be put at an entropy coding stage. According to the coded suppression strategy of the multi-domain JND model and the block perception-based distortion probability, the coding rate can be effectively reduced on the premise of guaranteeing certain subjective quality, and the compression ratio of the current coding standard is further improved.

A video coding method provided by the invention uses a fast Gaussian algorithm instead of a traditional SIFT method to extract feature points so that the extracted feature regions are more accurate and the range of key points is smaller; and meanwhile, and after the key points are extracted, corresponding regions of interest are generated, the coding rate of the regions of interest and regions of non-interest is reasonably adjusted and QP values of the two kinds of regions are properly debugged to retain feature information in each frame of an original video, the high quality requirements of the region of interest are achieved, and meanwhile the subjective quality of the entire video is ensured. The video coding method provided by the invention can retain the feature information as much as possible under the same code rate, so that a viewer (a machine) can recognize a specific target more accurately.

The embodiment of the invention provides a video coding rate determination method and device, equipment and a storage medium. The method comprises the steps that the frame type of a current frame to be coded of a video to be coded is determined, and the frame type is an interested frame or a non-interested frame; according to the frame type of the current to-be-coded frame, the pre-coding code rate of the current to-be-coded frame is adjusted to obtain a target coding code rate of the current to-be-coded frame; wherein if the frame type is an interested frame, the precoding code rate of the current to-be-coded frame is improved, and if the frame type is a non-interested frame, the precoding code rate of the current to-be-coded frame is reduced. In the embodiment of the invention, when a video to be encoded is encoded, a human eye vision theory can be combined with video encoding for each frame to be encoded, so that the subjective quality of the encoded video can be improved under thecondition of low encoding rate, and the subjective quality of the video can be guaranteed and the encoding rate can be saved under the condition of high encoding rate.

The application relates to a video encoding method for limiting quantization parameter. The method comprises the following steps: firstly performing prediction, and then reducing space redundancy andtime redundancy of a video image according to intra-frame prediction and inter-frame prediction; secondly performing conversion, removing the relevancy between adjacent data and the space redundancy through the conversion to a frequency domain from a time domain; and finally performing quantization, wherein the compression efficiency can be improved by adjusting the computed quantization parameterin different from the traditional method of directly adopting the computed quantization parameter, and the code stream waste is avoided; and encoding an encoding unit by adopting an entropy encodingway. By adopting the video encoding method disclosed by the application, the compression efficiency is improved and the bandwidth cost is reduced in the premise of guaranteeing the subjectivity quality.

The invention discloses a method and a device for coding images. The method includes dividing an image into code blocks and processing the code blocks; selecting processing techniques for the code blocks according to characteristics of coding coefficients of the image; scanning coding coefficients in reversed order; adaptively contracting brightness and chromaticity coefficients according to the selected processing techniques. The method and the device have the advantages that a reasonable process for contracting the coefficients is designed, so that values of high-frequency coefficients can be reduced without affecting the subjective visual quality, the coding rate is reduced, and the coding efficiency is improved.

The invention discloses an H.264 code rate control frame skipping optimization method, and solves the technical problem of buffer overflow or continuous frame skipping under the condition of scene switching or complex object motion. The method comprises the following implementation steps: setting initialization related parameters; calculating a target bit and a quantization parameter of the current frame; setting a frame skipping related threshold value; calculating the motion complexity of the current frame; calculating a bit factor of the current frame; performing special frame skipping processing on the first three frames; performing normative frame skipping processing from the fourth frame; encoding the current frame; and updating the relevant parameters after frame skipping, and performing frame skipping optimization on the next frame. According to the method, firstly, MAD is replaced with motion complexity, secondly, different buffer occupancy rates are set for different motion complexity, and finally, whether frame skipping occurs or not is judged by integrating the motion complexity, the buffer occupancy rates and bit factors of uncoded frames. The subjective quality of thevideo is effectively improved, and the method is mainly used for code rate control frame skipping optimization.

The invention discloses a video coding method based on a perceptual noise channel model, which comprises the following steps: S1, establishing a perceptual noise channel model considering visual jitter noise and just noticeable distortion (JND) noise; S2, dynamically estimating the quantification step length of visual jitter, calculating visual jitter noise, and calculating JND noise; S3, calculating a perception noise weight factor; S4, optimizing a rate-distortion cost function according to the perception noise weight factor; and S5, encoding a code tree unit (CTU) based on the optimized rate distortion cost function. Compared with the prior art, the method introduces the human eye visual perception characteristic, and can effectively save the video coding rate and improve the video compression performance on the basis of ensuring the good subjective quality of the coded video.

The invention discloses a dynamic point cloud coding rate distortion optimization method based on visual perception and partitioning. The method comprises the following steps: mapping color information of a character dynamic point cloud into a color video, and mapping geometric information into a geometric video; obtaining a tolerance threshold value of color distortion through the background brightness masking degree and the color texture masking degree of each pixel in the color video, and further obtaining a perception-based quantization parameter offset of each tree structure unit; obtaining a tolerance threshold value of geometric distortion through the geometric complexity masking degree of each pixel in the geometric video, and further obtaining a perception-based quantization parameter offset of each tree structure unit; combining the occupancy graph to obtain an occupancy graph-based quantization parameter offset of each tree structure unit in the color video and the geometric video; different quantization parameters are adopted for tree structure units belonging to the region of interest or the full perception region or the partial perception region or the non-perception region; the method has the advantages that the coding efficiency can be effectively improved, and the subjective quality can be ensured.