Abstract: The invention relates to a method of generating a down-sampled video from a coded video, said down-sampled video being composed of output down-sampled frames having a smaller format than input frames composing said coded video, said input coded video being coded according to a block-based technique and comprising quantized DCT coefficients defining DCT blocks, said method comprising an error decoding step for delivering a decoded data signal from said coded video, said error decoding step comprising at least a variable length decoding sub-step applied to said quantized DCT coefficients in each DCT block for delivering variable length decoded DCT coefficients defining, a prediction step for delivering a motion-compensated signal of a previous output frame, an addition step for adding said decoded data signal to said motion-compensated signal and resulting in said output down-sampled frames.

Abstract: The present invention relates to a transcoding device comprising partial decoding means (PD) for receiving a primary coded signal (S1) and providing a dequantized signal (IQS) including DCT coefficients ; quantization means (Q) for receiving the dequantized signal and providing a quantized signal (QS) using correction matrices (COR); and partial encoding means (PE) for receiving the quantized signal and providing a secondary coded signal (S2). Such a transcoding device allows the primary signal encoded at a first bit rate to be converted into the secondary signal encoded at a second bit rate lower than the first one while an optimum signal quality is maintained.

Abstract: The present invention relates to a transcoding device comprising partial decoding means (PD) for receiving a primary coded signal (S1) and providing a dequantized signal (IQS) including DCT coefficients; quantization means (Q) for receiving the dequantized signal and providing a quantized signal (QS) using correction matrices (COR); and partial encoding means (PE) for receiving the quantized signal and providing a secondary coded signal (S2). Such a transcoding device allows the primary signal encoded at a first bit rate to be converted into the secondary signal encoded at a second bit rate lower than the first one while an optimum signal quality is maintained.

Abstract: In accordance with the MPEG-2 standard for compression of a digital signal representative of a video image, the image is separated into groups of several different types of pictures and those of each type are encoded by respective encoders. Depending on the complexity and bitrates of each picture, the bitrates of the encoders may vary and so must be restored to a constant bitrate by respective output buffers. Also, the global sum of the contents of the individual buffers must be maintained substantially constant so as to provide a constant global bitrate. The invention provides a method and apparatus for bitrate control of each encoder based on a measure of the complexity of the picture being processed thereby and the bitrates which are required in order to maintain a substantially equivalent quality of the pictures encoded by the respective encoders.

Abstract: An infra-red telemeter comprises a pilot oscillator 1 and a controlled oscillator 2 kept in phase with the pilot oscillator 1. The controlled oscillator 2 provides the modulation frequency for transmission, either directly for fine measurement or via a counter 11 which divides by M. for coarse measurement, while the pilot oscillator 1 provides a heterodyne frequency, either directly or after division by N in a counter 17, respectively. After the received modulation signal has been mixed with the heterodyne frequency, a phase detector 18 compares the phase of the mixed signal with the phase of a reference low frequency obtained by the frequency of oscillator 1 being divided by H in counter 17. The phase servo loop operates continuously, in the case of both fine and coarse measurement.