35 results about "Video quality degradation" patented technology

System and method to detect video quality degradation in a video stream received by a telecommunications endpoint, the method including: locating reference features characteristic of content in the received video stream; calculating reduced reference features from the located reference features; receiving reduced reference features of a transmitted video stream, the transmitted video stream corresponding to the received video stream; calculating a distance between the reduced reference features in the received video stream and the reduced reference features of the transmitted video stream; and detecting video quality degradation when the calculated distance exceeds a predetermined threshold.

The invention provides a photographing parameter setting method and a mobile terminal. The problem that the quality of camera photographing and videos is deteriorated, which is caused by conflicts generated by a camera working according to different control information of different controllers, is solved. The setting method provided by the invention comprises the steps that the scene feature information of a photographing scene is acquired when the camera acquires a preview image; different photographing parameters are set for each camera application according to the scene feature information; and the camera applications are applications which call the default components of the camera to realize default functions. According to the invention, the problem that conflicts are easily generated by the camera which works according to different control information sent by different controllers is avoided, and the effect of the image finally output by the camera is effectively improved.

In estimating subjective video quality corresponding to main parameters which are input as an input frame rate representing the number of frames per unit time, an input coding bit rate representing the number of coding bits per unit time, and an input packet loss rate representing a packet loss occurrence probability of an audiovisual medium, a degradation model specifying unit specifies a degradation model representing the relationship between the packet loss rate and the degradation in reference subjective video quality on the basis of the input frame rate and input coding bit rate. A desired subjective video quality estimation value is calculated by correcting the reference subjective video quality on the basis of a video quality degradation ratio corresponding to the input packet loss rate calculated by using the degradation model.

The invention discloses a media stream transmission method and device and aims to solve the problem that the audio and video quality is reduced in the media stream transmission process due to reasons such as packet loss, jitter and / or link breaking in the prior art. The method comprises the following steps: according to a link-building request message sent by a calling terminal and a response message from a called terminal for the link-building request message, conducting media ability negotiation between the calling terminal and the called terminal, and building at least two media channels; according to the negotiated media ability, conducting a media stream transmission through a first media channel; when detecting that an exception occurs in the media stream transmission of the first media channel, selecting the rest one media channel in the at least two media channels as a second media channel, and switching a media stream from the first media channel to the second media channel to be transmitted. The audio and video quality of two communication parties can be ensured through the method and the device.

The embodiment of the invention discloses bandwidth control method, device and system. The method comprises the following steps of: firstly, acquiring the current video sequence complexity information of each path of video signals; then quantifying the current video sequence complexity information of each path of video signals and obtaining a current video sequence complexity grade of each path of video signals according to the complexity information; and finally, distributing a total bandwidth to each path of video signals according to the current video sequence complexity grade of each path of video signals. The invention can achieve the purpose of dynamically distributing the bandwidth of each path of video signals so as to reasonably utilize the total bandwidth and reduce the occurrence probability of video quality reduction.

The invention discloses a multipoint control unit cluster system and method. The system is composed of a media control server (MCS) and a media processing server (MPS). The MCS receives conference information sent by a conference management server, and allocates one or more Multiple MPS for the conference. The MCS multicasts or unicasts the received media streams of the terminals to all the MPSs that provide media processing services for the conference. Each MPS is responsible for the media processing of some of the terminals, performing audio mixing or multi-screen synthesis, and encoding The final media stream is sent to the MCS, and then forwarded to the corresponding terminal by the MCS. When the MCS discovers that an MPS is offline or needs to be maintained, the MCS saves the call information responsible for the MPS into a list to be processed, and migrates the calls to other available MPS one by one, and the terminal calls are still maintained. Connection Status. The invention can solve the problems of media stream delay and audio and video quality degradation caused by MCU cascading, and has simple control logic, high reliability and fault recovery.

The invention discloses an MPEG-2 (Moving Pictures Experts Group-2) to H.264 fast video transcoding method, comprising the following steps of: firstly saving coding macro block modes of macro blocks in a P frame, coding block modes of the macro blocks and four 8*8 direct current coefficients in the macro blocks in MPEG-2 original video decoding process; secondly dividing all macro blocks in the Pframe into five different types of macro blocks according to the saved coding macro types and the coding block modes; thirdly, only self-adaptively selecting the optimal coding mode from the coding modes having larger relativity with the performances of the macro blocks to code the macro blocks in the H.264 coding process. The method largely reduces the number of candidate coding modes for coding the macro blocks in the P frame in the premise of ensuring that the reduction of the video quality is a little and the increment of the code rate is not much, thereby effectively reducing the time complexity of macro code coding mode selection in the H.264 coding process, and reducing the MPEG-2 to H.264 video transcoding time, i.e. improving the MPEG-2 to H.264 video transcoding efficiency.

The invention discloses a partial reconstruction-based quality optimization method for scalable video coding. The method comprises the following steps of: setting a truncation degree and a layer weight; performing partial reconstruction or entropy coding on a residual error conversion coefficient; calculating macro block distortion of a base layer and an enhancement layer; selecting an optimal mode for determining base layer macro blocks; traversing all macro blocks in a coding frame on the base layer so as to obtain the code stream of the base layer; selecting an optimal mode for determiningenhancement layer macro blocks; traversing all macro blocks in a coding frame on the enhancement layer so as to obtain the code stream of the enhancement layer; and calculating and storing error diffusion distortion and error diffusion sensitivity. In the method, the residual error conversion coefficient is selectively truncated in a coding process, so that combined optimization of video quality at different target code rates is realized, and the problem of video quality reduction caused by the conventional code stream extraction method is solved; and simultaneously, an improved code stream extraction algorithm is used in a combined way, so that video quality is further enhanced.

The invention discloses an information hiding method of HEVC video based on Hamming code+1, which utilizes the Hamming code+1 algorithm formed by combining the (1,3,2) matrix coding algorithm and the LSBMR algorithm in steganographic coding, according to the The embedded three-bit secret information modifies the prediction mode to complete the information embedding, and embeds three-bit secret information in four consecutive 4×4 intra-frame luminance blocks, which not only ensures the hidden capacity, but also reduces the risk of video quality degradation caused by the modification of the prediction mode. Influence, which well guarantees the subjective and objective quality of the video, and greatly reduces the impact of embedding hidden information on the video stream; by analyzing the HEVC codec structure, for the prediction unit with a size of 4×4, the intra-frame prediction coding process The medium modulation prediction mode is the prediction mode with the smallest rate-distortion cost that meets the embedding conditions, and uses the Lagrangian rate-distortion model to adaptively select the prediction unit type of the coding unit. This hidden information embedding method can well ensure that the video subjective and objective quality.

The invention discloses a video deinterlacing method and device used for solving a problem of output video quality degradation due to indiscriminate deinterlacing treatment for different application scenes in the prior art. The video deinterlacing method includes reading video frames contained in an input video flow frame by frame and recognizing and reading static areas and roll title areas in the read video frames separately; performing deinterlacing treatment on the recognized static areas, the roll title areas and motion areas separately, wherein the motion areas include areas in the videoframes except the static areas and the roll title areas.