摘要:
The invention relates to a device for coding video frame sequences, comprising means (1) for measuring the spatial activity of the video frames to be coded, means (1) for measuring the temporal activity of the video frames to be coded, means (2) for coding the frames as a frame structure or as a field structure. According to the invention, the means (2) for coding the frames as a frame structure or as a field structure are able to choose the field or frame structure dynamically as a function of the measurements of spatial and temporal activity of the said frame.
摘要:
The invention relates to a device for coding video frame sequences, comprising means (1) for measuring the spatial activity of the video frames to be coded, means (1) for measuring the temporal activity of the video frames to be coded, means (2) for coding the frames as a frame structure or as a field structure. According to the invention, the means (2) for coding the frames as a frame structure or as a field structure are able to choose the field or frame structure dynamically as a function of the measurements of spatial and temporal activity of the said frame.
摘要:
A device and a method for coding video images by motion compensation. The device incorporates a coding unit and a filtering unit. A calculation unit for calculating a recursivity coefficient as a function of an estimated noise level and a prediction error, a measurement unit for measuring the intra-image correlation and the inter-image correlation, a selection unit for selecting a type of coding applied to the current input image as a function at least of the measurements of the inter-image correlation and of the measurements of the intra-image correlation and as a function of the estimated noise level, a coding unit for coding the current input image as a function of the type of coding selected.
摘要:
The invention relates to a device and a method for coding video images by motion compensation. The device according to the invention incorporates incorporated means of coding and means of filtering. It comprises means of calculation of a recursivity coefficient as a function of an estimated noise level and of a prediction error, means of measurement of the intra-image correlation and of the inter-image correlation, means of selection of a type of coding applied to the current input image as a function at least of the measurements of the inter-image correlation and of the measurements of the intra-image correlation and as a function of the estimated noise level means of coding of the current input image as a function of the type of coding selected.
摘要:
The invention relates to a process for coding digital data of a video sequence for its transmission and a variable bit rate. It is characterized in that the bit rate regulation in respect of the image at the instant n is performed as a function of a bit rate prediction in respect of the transmission channel for the instant n+&tgr;, &tgr; being a constant time between the instant of storage of an image in the buffer of the coder and the instant of output of this image from the buffer of the decoder.
摘要:
Image sequences are advantageously recoded based on an evaluation of complexities before and after trans-coding of the images. Initially, information is extracted representing at least the complexity of recoding each image. A complexity ratio is calculated in accordance with the complexities of images recoded previously using the aforementioned mode to the complexities of the initial coding of said images. After smoothing the complexity ratio undergoes updating. Each image is recoded according to the mode by estimating the complexity of each image to be recoded as the product of the complexity of the initial coding of the image by the smoothed complexity ratio for the mode.
摘要:
The invention relates to a device for recoding images, using a given set throughout, from a video stream comprising image sequences initially coded according to at least one mode. The inventive device comprises: means of extracting information which is associated with the recoding of images, said information representing at least the complexity of recoding each image; means of extracting information, such as coding complexity information, which is associated with the initial coding of the images; means of calculating a ratio, called the complexity ratio, of the complexities of recoding images recoded previously using the aforementioned mode to the complexities of the initial coding of said images; means of updating a smoothed complexity ratio for said mode according to the complexity ratio; and means of recoding each image according to said mode by estimating the complexity of each image to be recoded as the product of the complexity of the initial coding of said image by the smoothed complexity ratio for said mode. The invention is suitable for MPEG-2 and H26L coding.
摘要:
The present invention relates to a method and a device for monitoring the quality of video data having to undergo coding and decoding, making it possible to maintain predetermined constant quality of the video data after decoding. The method is such that information representing the complexity of video data to be coded is received from at least one coder. For each video-data item to be coded, a reference quantization value is calculated as a function of the complexity. For each video-data item to be coded, a reference throughput calculated as a function of the reference quantization value and of the value of the predetermined constant quality is calculated and transmitted to the coder, allowing the coder to code each video data item so as to obtain video data at the predetermined quality, after decoding.
摘要:
The invention relates to a process, to a device for smoothing dark regions of images and to a coding system. a noise level is associated with each image and a luminance value is associated with each pixel, a threshold value is calculated, at least two values delimiting a smoothing range are defined, for each current pixel, the luminance of the pixel is compared with the said values, if the luminance of the current pixel lies in a smoothing range, the luminance of several pixels in an analysis window is compared with the said values, if the luminance of certain pixels lies in the same range as the value of the luminance of the current pixel, the value of the luminance of the current pixel is modified as a function of the said threshold values.
摘要:
A device for regulating bit rate in a system for statistically multiplexing several streams of MPEG 2 coded images is disclosed. The statistical multiplexing system includes a device (1) for allocating bit rate using the complexity calculated by a bit rate regulating device (10). Each coder E(i) of an image stream includes a first coding device (20) for performing spatial coding, a second coding device and a memory for storing the complexity X1st| of the last image coded spatially by the first coding device. The complexity (X−GOP) of the last group of pictures is coded by the second coding device (30). Device (10) regulates the bit rate of coder E(i) for determining the complexity value for the next image coded by the second coding device (30), using stored complexity values. This complexity value is transmitted to the bit rate allocator (1) to determine the next bit rate sent to the coder E(i).