Thomson Licensing

Thomson Licensing S.a.

Other

Nextream France

Nextream S.a.

Thomas Broadcast Systems

Patrice Alexandre

Xavier Ducloux

Ludovic Noblet

Olivier Le Meur

Claude Perron

Jean-Yves Babonneau

Jean-Luc Soulard

Jean-Louis Yves Diascorn

Patrick Dumenil

Jean Chatel

Pascal Gravoille

Gildas Guelou

Thierry Lavenan

Jean-Christophe Morizur

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.

Device and method for recoding a video data stream

The invention lies within the area of image compression coding, in particular of MPEG type, which uses recoding help data. The invention affords a solution for reusing the help data selectively. To this end, the invention adjoins an electronic signature representative of the constraints of the coder. Thus, it becomes possible to determine whether the help data are reusable or not for a subsequent coding using other constraints.

Method of coding a video image stream with a view for subsequent recoding using the same type of code

The invention relates to a device for coding video frame sequences, comprising According to the invention, the means () 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.

Device and method for coding video data

A multiplexing device is coupled to various coding devices. The multiplexing device does not attempt to mutually synchronize the various coding devices but, instead, circumvents such synchronization while making it possible to work with the various coding devices and to obtain synchronous actions at the input of the multiplexer. In particular, the multiplexing device transmits control commands and an instant of action to each of the coding devices.

Device and method for multiplexing associated with a coding device

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.

Device and process for coding video images by motion compensation

The invention relates to a process, to a device for smoothing dark regions of images and to a coding system.

Spatial smoothing process and device for dark regions of an image

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.

Method and device for controlling the quality of video data

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 ( ) for allocating bit rate using the complexity calculated by a bit rate regulating device ( ). Each coder E(i) of an image stream includes a first coding device ( ) for performing spatial coding, a second coding device and a memory for storing the complexity X &verbar; of the last image coded spatially by the first coding device. The complexity (X ) of the last group of pictures is coded by the second coding device ( ). Device ( ) regulates the bit rate of coder E(i) for determining the complexity value for the next image coded by the second coding device ( ), using stored complexity values. This complexity value is transmitted to the bit rate allocator ( ) to determine the next bit rate sent to the coder E(i).

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Cesson Sévigné, France

Patrice Alexandre