35 results about "Video quality degradation" patented technology

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 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 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.