429 results about "Subjective quality" patented technology

The apparatus for constructing a multi-channel output signal using an input signal and parametric side information, the input signal including the first input channel and the second input channel derived from an original multi-channel signal, and the parametric side information describing interrelations between channels of the multi-channel original signal uses base channels for synthesizing first and second output channels on one side of an assumed listener position, which are different from each other. The base channels are different from each other because of a coherence measure. Coherence between the base channels (for example the left and the left surround reconstructed channel) is reduced by calculating a base channel for one of those channels by a combination of the input channels, the combination being determined by the coherence measure. Thus, a high subjective quality of the reconstruction can be obtained because of an approximated original front/back coherence.

By utilizing parameters derivable from a compressed bit-stream, measures are obtained of the subjective quality of a decoded picture, without the necessity for reference to source material. A blockiness measure is derived both locally and globally and used to control a de-blocking filter. An estimate of signal-to-noise ratio is derived from quantization values.

A subjective quality monitoring system for packet based multimedia signal transmission systems estimates the parameters of a statistical model representing the probabilities of said packet based transmission system being in a low loss state or a high loss state and uses said estimates to predict the subjective quality of the multimedia signal. The quality monitoring system comprises a plurality of quality monitoring functions located at the multimedia to packet conversion points.

Speech signal classification and encoding systems and methods are disclosed herein. The signal classification is done in three steps each of them discriminating a specific signal class. First, a voice activity detector (VAD) discriminates between active and inactive speech frames. If an inactive speech frame is detected (background noise signal) then the classification chain ends and the frame is encoded with comfort noise generation (CNG). If an active speech frame is detected, the frame is subjected to a second classifier dedicated to discriminate unvoiced frames. If the classifier classifies the frame as unvoiced speech signal, the classification chain ends, and the frame is encoded using a coding method optimized for unvoiced signals. Otherwise, the speech frame is passed through to the “stable voiced” classification module. If the frame is classified as stable voiced frame, then the frame is encoded using a coding method optimized for stable voiced signals. Otherwise, the frame is likely to contain a non-stationary speech segment such as a voiced onset or rapidly evolving voiced speech signal. In this case a general-purpose speech coder is used at a high bit rate for sustaining good subjective quality.

The invention discloses a coding method for a three-dimensional video. The method comprises the following steps of: inputting a first frame image which comprises image texture information and depth information at a plurality of different viewpoints at the same time so as to form depth pixel images of the plurality of the viewpoints; selecting a viewpoint which is closest to a center as a main viewpoint and mapping the depth pixel image of each viewpoint onto the main viewpoint; acquiring motion information from the texture information by a motion target detection method, rebuilding all depth pixel points in the mapped depth pixel images by using the depth information and/or the motion information to acquire a background image layer image and one or more foreground image layer images; and coding the background image layer image and the foreground image layer images respectively, wherein the depth information and the texture information are coded respectively. The invention also discloses a decoding method for the three-dimensional video, a coder and a decoder. The coding method is particularly suitable for coding a multi-viewpoint video sequence with a stationary background, can enhance prediction compensation accuracy and decreases code rate on the premise of ensuring subjective quality.

A linear prediction coefficient of a signal represented in a frequency domain is obtained by performing linear prediction analysis in a frequency direction by using a covariance method or an autocorrelation method. After the filter strength of the obtained linear prediction coefficient is adjusted, filtering may be performed in the frequency direction on the signal by using the adjusted coefficient, whereby the temporal envelope of the signal is transformed. This reduces the occurrence of pre-echo and post-echo and improves the subjective quality of the decoded signal, without significantly increasing the bit rate in a band extension technique in the frequency domain represented by SBR.

A video encoding/decoding system based on 3D wavelet decomposition and the human perceptual model is implemented. JND is applied in quantizer design to improve the subjective quality of compressed video. The 3D wavelet decomposition helps to remove spatial and temporal redundancy and provides scalability of video quality. In order to conceal the errors that may, occur under bad wireless channel conditions, a slicing method and a joint source channel coding scenario, that combines RCPC with CRC and utilizes the distortion information to allocate convolutional coding rates are proposed. A new subjective quality index based on JND is presented and used to evaluate the overall system performance at different signal to noise rations (SNR) and at different compression ratios. Due to the wide use of arithmetic coding (AC) in data compression, it is considered as a readily available unit in the video codec system for broadcasting. A new scheme for conditional access (CA) sub-system is designed based on the compression graphic property of arithmetic coding. Its performance is analyzed along with its application in a multi-resolution video compression system. This scheme simplifies the conditional access sub-system and provides satisfactory system reliability.

The embodiment of the invention discloses method and device for processing images in quantification, which improve the subjective quality of quantification-coded images on a simpler basis without affecting the performance of a coding and decoding system. The method comprises the following steps of: converting an image block to obtain a conversion coefficient matrix corresponding to the image block; dividing regions for the conversion coefficient matrix according to a pre-set division mode; counting a statistic of each divided region; and carrying out the quantification adjustment on the corresponding region in the conversion coefficient matrix of the image block according to the statistic of the region.

The invention discloses a method, a device and a system for compressing and decompressing transparent images and belongs to the field of digital images. The method comprises the following steps of: acquiring color channel information and transparent color channel information of original transparent images; performing loss compression on the color channel information to obtain color channel compression information, and performing lossless compression on the transparent color channel information to obtain transparent color channel compression information; and performing compression data synthesis on the color channel compression information and the transparent color channel compression information to obtain compressed transparent images. By the scheme provided by the invention, the transparent color channel information of the transparent images is subjected to lossless compression, while the color channel information is subjected to loss compression, the compressed transparent color channel information and color channel information are organized according to a specific format, redundancy contained in the image information is removed to the greatest extent, the compression efficiency of the transparent images is improved and the subjective quality of the images is not obviously reduced.

The invention relates to a quality assurance (QA) system of internet protocol television (IPTV) services, comprising a management server which is arranged at the head end of an IPTV system and subjective quality estimation devices which are arranged at each IPTV terminal respectively, wherein the management server is connected with the subjective quality estimation devices by IPTV system networks, and the subjective quality estimation devices are integrated into a service quality measurement and control module in a set top box (STB) of each IPTV terminal. The invention also relates to a QA method of IPTV services by using the system. In the method, the service quality measurement and control module is used for measuring and controlling the service quality of a video which is played by the STB of the IPTV terminal so as to acquire the subjective quality score; and the subjective quality score is compared with a threshold, and if the subjective quality score is lower than the threshold, an alarm is sent out, thus realizing subjective quality estimation for the client of the IPTV system, and perfecting the quality detection modes of the IPTV services. The system provided by the invention is simple in structure, and the method provided by the invention is low in operating cost and easy and convenient in application modes.

The invention provides a scalable video coding method where a region of interest has transmission priority. In the method, the region of interest is treated with default setting or optionally chosen by a user at a receiving terminal during coding. The bit stream of an enhancement layer is treated in different manners according to the fact that whether an instruction is received from the region of interest (ROI) when the instruction is sent. If the instruction from the ROI is not received, the encoded bit stream is packed according to a preset order and an obtained channel bandwidth; if the instruction from the ROI is received, a coding and recoding module recodes after coding according to the position and the size of the region of interest and has the transmission priority so as to ensure that the region of interest of the user at the receiving terminal is more clear to improve the subjective quality of the video. When an encoded video streaming media is transmitted or a quasi-real-time video is transmitted by the scalable video coding method of the invention, the user at the receiving terminal can optionally choose the region of interest and the video effect of the region of interest can be greatly improved, therefore, not only precious transmission bandwidth resources is saved, but also the subjective quality of the video is improved.

The invention provides an HEVC (High Efficiency Video Coding) code rate control method based on region-of-interest. The HEVC code rate control method based on region-of-interest comprises the steps: generating a spatial domain significance graph of the current frame according to a GBVS (Graph Based Visual Saliency) model; generating a time domain significance graph of the current frame through motion vector information; integrating the time domain significance graph and the spatial domain significance graph by using the consistency normalization method to obtain the eventual significance graph; performing regional division for the current frame image by using the significance graph so as to divide the region into a region-of-interest and a non-region-of-interest; performing bit distribution for the region-of-interest and the non-region-of-interest respectively; performing bit distribution for each LCU in the current frame according to the significance; calculating lambda and a QP (Quantization Parameter) value according to the distributed code rate, and clipping and correcting the lambda and the QP value; and performing coding by using the eventually obtained lambda and the QP value. The HEVC code rate control method based on region-of-interest can improve the subjective quality for video coding and accurately control the output bit at the same time.

In accordance with the present invention, a portion of a packetized data stream is copied from a data network without interfering with the flow of the data in the network. A known test signal is then substituted for the information contained in each copied packet to prepare a pseudo-media packet stream. The known test signal is encoded and packetized using the same methods used for the copied data stream. The pseudo-media signal is then recovered from the pseudo-media stream using the same depacketizing and decoding methods to be used on the copied packetized data stream. The recovered signal is an accurate representation of the state of the media stream since it has gone through the same packetization/depacketization and encoding/decoding procedures and includes all of the same faults of the copied data stream. The subjective quality of the recovered signal is then measured providing an accurate measure of the subjective quality of the copied media stream.

The invention relates to a video quality automatic evaluation method and an evaluation method, relating to the evaluation of wireless video communication, which can confirm the evaluation property, reduce needed reference data and reduce calculation complexity, therefore, the evaluation mode is adaptive to the evaluation application facing wireless network. The method comprises: processing content pre-check on the reference video not compressed; according to the average activity of each activity region, dividing the check on the video characters into high and low activity region character checks, to attain the check parameters representing the spatial domain and time domain characters which express the characters of the video sections in each activity region; weighting the check parameters of the spatial domain and time domain characters of each activity region to build the spatial domain and time domain character parameters of the whole video, realizing the projection between the check parameters and the subjective quality expression according to a preset video quality evaluation database, to realize the automatic evaluation on the video quality facing wireless network.

Disclosed is a method and device for realizing quantification in coding/decoding, which mainly comprises: firstly, quantification used in image switching coefficient matrix adopts quantification form of parameter model, the parameter model is a parameter model which needs only several parameters to present and it includes a frequency band distributing structure and frequency band parameters. Thereby, the quantified matrix satisfying human eye visual properties is obtained by the control of several parameters, and the subjective quality of image after coding is controlled and quantified; secondly, the method does not need to transmit or memorize the quantified matrix in codes flow, thus the coding efficiency is improved; finally, for the quantified computation of the image switching coefficients, this method can well adapt to the character of the content information in the image. Thus, this invention can improve subjective quality of the image after quantified coding.

The invention discloses a method for video or image deblocking filter and the device thereof. According to the block types of the two sides of a boundary and a motion vector, whether to perform deblocking filter is judged, and a needed filter strength when deblocking filter is needed is selected, and then deblocking filter is carried out in accordance with the filter strength and image content. Compared with current deblocking filter method, the deblockign filter method can improve the objective quality and the subjective quality of an image and the adaptability of filter without increase of calculation complexity and storage complexity.

Systems and methods of perceptual quality monitoring of video information, communications, and entertainment that can estimate the perceptual quality of video with high accuracy, and can be used to produce quality scores that better correlate with subjective quality scores of an end user. The systems and methods of perceptual quality monitoring of video can generate, from an encoded input video bitstream, estimates of one or more quality parameters relating to the video, such as the coding bit rate parameter, the video frame rate parameter, and the packet loss rate parameter, and provide these video quality parameter estimates to a predetermined video quality estimation model. Because the estimates of the video quality parameters are generated from the encoded input video bitstream as it is being received, the systems and methods are suitable for use as QoE monitoring tools.

The invention discloses a video service quality-based hybrid selective repeat method, which mainly solves the problems of reduced data transmission quantity, large transmission delay and poor video information continuity caused by unnecessary cost in the prior art. The method is implemented by the following steps of: first, calculating a video subjective quality objectified value by utilizing a video subjective quality objectifying model, and calculating a data transmission redundancy range which cannot cause network congestion by using a network broadband which feeds back from a receiving end to a transmitting end; then, according to the data transmission redundancy range, allocating proportions to forward error correction redundancy and selective repeat redundancy to optimize the video subjective quality objectified value; and finally, selecting a code pattern for coding according to the forward error correction redundancy, and determining the number of packets needing to be repeated according to the selective repeat redundancy. In the method, forward error correction control and selective repeat error control are taken into consideration at the same time, so that the time cost and the network cost are reduced; therefore, the method can be used in a video transmission system.

The invention discloses a coding mode selection method for HEVC (high efficiency video coding). The method comprises the step of prejudging CTU partition mode, CU coding mode and PU interframe coding mode in the HEVC according to the space and time domain features in the current coding image content, so the traverse quantity in the mode selection in an HEVC frame is reduced. The HEVC efficiency is improved under the premise of not influencing the image coding quality. The code stream output by the method accords with the HEVC standards, the coding mode selection can be realized by further combining the perception characteristic of the vision of a human eye, and the subjective quality of the coded image is improved.

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.

A subjective quality estimating part (11) receives an undeteriorated reference video signal (RI) and a deteriorated video signal (PI) produced from the reference video signal, calculates video signal feature values for both the signals, and according to a difference between the calculated video signal feature values of the signals, estimates a subjective quality of the deteriorated video signal. A feature value calculating part (12) calculates the video signal feature values of the reference video signal. A correction information storing part (13) stores correction information that corresponds to video signal feature values and is used to correct the subjective quality. A correction calculating part (14) receives the video signal feature values of the reference video signal from the feature value calculating part (12), retrieves correction information corresponding to the received video signal feature values from the correction information storing part (13), and transfers the retrieved correction information to a correcting part (15). According to the transferred correction information, the correcting part (15) corrects the subjective quality estimated by the subjective quality estimating part (11).