Koninklijke Philips Corporation N.V.

U.S. Phillips Corporation

Anthony Morel

Arnaud Bourge

The present invention relates to a method of transcoding () a primary encoded signal (S) into a secondary encoded signal (S). Said transcoding method comprising at least a step of decoding a current picture of the primary encoded signal, said decoding step comprising a dequantizing sub-step () for producing a first transformed signal (R), an encoding step, following the decoding step, for obtaining the secondary encoded signal, said encoding step comprising a quantizing sub-step (), and a step of predicting a transformed motion-compensated signal (Rmc) from a transformed encoding error (Re) derived from the encoding step, said prediction step being situated between the encoding and decoding steps. Said method of transcoding further comprises a filtering step (), between the dequantizing sub-step and the quantizing sub-step, for obtaining a better picture quality for low bitrate applications.

Method of transcoding and transcoding device with embedded filters

A video bitrate control method for a video coding system, the coding system generating coded video frames to be stored in a storage device and originating from a sequence of input frames, the method comprising at least a quantization step for applying to the input frames a quantization factor issued from an evaluation step. The evaluation step uses statistics relative to previous coded frames to evaluate a complexity of the current frame to be coded. In parallel, a current bit target for the frame being coded is estimated in relation to the remaining space available in the storage device and the remaining number of frames to be coded in the sequence. Then the quantization factor is derived on the basis of the estimated complexity and the estimated current bit target. This results in an output bitrate for coded frames having CBR or VBR behaviors, leading to a constant quality of the coded video frames, while guaranteeing an optimal filling of the storage device.

Video bitrate control method and device for digital video recording

Transcoding method and device

The invention relates to a transcoder comprising a drift compensating loop (DCL) for compensating a drift signal (Ei) introduced in the transcoding path by a quantization operation (Q2). This drift compensation loop performs a motion compensation of a signal (F1) issuing from a previous dequantization (IQ1) resulting in a prediction signal (P1). The motion compensation is based on the drift signal stored in a memory unit (MEM). The drift signal and the prediction signal may be conveyed in an interlaced or de-interlaced structure. According to the invention, an AMC unit adapts the motion compensation operation with the de-interlaced or interlaced structures of the drift and prediction signals.

Drift-free transcoder and related method

By inserting a downsampling filter between the decoding and re-encoding parts of a transcoder, a reduced resolution transcoding is performed. Before transferring the decoded motion vectors to the encoding part, the motion vectors are processed by additional operations provided in order to take into account the fact that macroblocks before and after the resizing step no longer match.

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Saint Maur des Fosses, France

Anthony Morel