Ecole De Technologie Superieure

Vantrix Corporation

Other

Socovar, Limited Partnership

Stéphane Coulombe

Steven Pigeon

Soroosh Rezazadeh

Jean-François Franche

Maged E Beshai

Didier Joset

Christian Desrosiers

Luc Trudeau

Isabelle Metoevi

Jean-Francois Franche

Francois Caron

Firouzeh Golaghazadeh

Mohammadreza Jamali

Hicham Layachi

Guangyi Chen

Francis Roger Labonte

Carlos Vazquez

Vivien Boussard

François Caron

Esmaeil Hojati

A computer-implemented technique for correcting a data packet having a payload and cyclic redundancy check information provides a list of possible packet errors by algorithmic operations of forcing and cancelling bits at certain positions using a generator polynomial, while maintaining the equivalence relationship with the original syndrome, performed explicitly using arithmetic operations or implicitly using a table representative of such arithmetic operations. Correction can then be implemented using an error chosen from the list.

Methods and systems for bit error determination and correction

A method, device and system for correcting errors in a group of received packets having a redundant packet. The method includes determining an inconsistent bit indicator for a bit position of the packets, determining a bit reliability indicator indicative of a potential bit error location in at least one packet, calculating a number of potential bit error locations for the bit position and identifying a correctable bit location accordingly. A method, device and system for correcting an error in a received packet. The method is adapted to calculate a checksum value of the received packet, verify if the checksum value is indicative of at least one bit error in the received packet, identify a predefined Checksum Pattern Type (CPT) according to the checksum value and determine at least one bit error event (BEE) accordingly. A method, device and system for decoding a plurality of received fountain encoded symbols.

Checksum-aided forward error correction of data packets

Checksum-filtered decoding, checksum-aided forward error correction of data packets, forward error correction of data using bit erasure channels and sub-symbol level decoding for erroneous fountain codes

Methods and systems for determining motion vectors in a motion estimation process of a video encoder are provided. Embodiments of the present invention provide a solution for the problem of unnecessary cost function evaluations, found when combining the successive elimination method with a predetermined list of candidate motion vectors search ordering. In order to solve this problem, embodiments of the present invention provide an adaptive scan ordering of block matching candidates within a search area. Advantageously, embodiments of the present invention will only evaluate necessary cost functions, without impacting rate-distortion.

Methods and systems for determining motion vectors in a motion estimation process of a video encoder

A video intermodal transcoder converts a compressed bitstream formulated according a type-1 compression scheme to a type-2 compressed bitstream formulated according to a type-2 compression scheme. The transcoder includes an augmented type-1 decoder, a transcoder kernel, and an augmented type-2 encoder. The transcoder kernel performs processes of creating motion-vector candidates and pre-computing prediction errors for each cell of a predefined image coding block and for each candidate motion vector for repetitive use in evaluating various image partitions. In an implementation where the type-1 compression scheme follows the H.264 standard and the type-2 compression scheme follows the HEVC standard, the transcoder exploits the flexibility of the coding-tree structure and other HEVC features to significantly reduce the bit rate of the compressed bit stream. The pre-computation of prediction errors significantly reduces the processing effort, hence increases the throughput of the transcoder.

Method and apparatus for video intermodal transcoding

A method and apparatus for optimal signal encoding based on reference data relating encoded-signal characteristics to encoding parameters are disclosed. Reference vectors of encoding parameters and corresponding measurements of encoded-signal characteristics are used to establish a functional relationship between each characteristic and the encoding parameters. Candidate vectors of encoding parameters are identified based on user-defined boundaries of both the encoding parameters and acceptable encoded-signal characteristics. A figure of merit is determined for each candidate vector and the candidate vector of highest figure of merit is presented to an encoder.

Optimal signal encoding based on experimental data

Methods and systems for encoding video data are provided. Evolving standards for video encoding such as High Efficiency Video Coding (HEVC) standard require a significant increase in computational complexity for both inter and intra encoding. The method includes calculating an approximate cost of each of a first set of prediction modes. Then selecting a second set of prediction modes from the first set of prediction modes based on probability distributions associated with each of the modes in the first set of prediction modes, the second set having substantially fewer prediction modes than the first. A number of candidate prediction modes prior to rate distortion optimization (RDO) is reduced. Experimental results show that the proposed method provides substantial time reduction and negligible quality loss as compared to the HEVC reference.

Method and system for fast mode decision for high efficiency video coding

Methods and systems for parallel rate-constrained motion estimation in a video encoder are provided. Embodiments of the present invention provide a solution for the problem of the reliance upon spatial dependencies when processing parallel RCME on a frame. In order to solve this problem, embodiments of the present invention determine a list of at least two Motion Vector Predictor Candidates (MVPC), determine, in parallel for at least two of said at least two MVPCs, corresponding Motion Vector Candidates (MVC) using Rate-Constrained Motion Estimation (RCME) and determine the optimal Motion Vector (MV) among the determined MVCs based on rate distortion optimization.

Method and system for parallel rate-constrained motion estimation in video coding

A video encoder with rate-constrained search ordering feature for reducing computational cost of motion estimation in video coding has been provided. The video encoder has a motion estimation module for determining vector encoding costs for respective motion vectors corresponding to candidate blocks in a video frame, and assigning an order for evaluating a rate-constrained cost of each candidate block based on the determined vector encoding costs.

Video encoder and motion estimation apparatus therefor with rate-constrained search ordering of candidate blocks

System and method for optimizing a transcoding session between multiple terminals are disclosed. The method determines properties of the transcoding session, including a number of terminals participating in the transcoding session, media characteristics supported by each terminal, a measure of performance of the transcoding session to be optimized, and optionally a proportion of time involved in the transcoding session for each terminal. Then a cost function characterizing the measure of performance of the transcoding session and depending on the above properties of the transcoding session is built, followed by optimizing the cost function with respect to said measure of performance to determine an optimal measure of performance for the transcoding session and optimal values for the media characteristics for each terminal. In one embodiment, codecs used by multiple terminals and computational complexity of the transcoding session are optimized. A corresponding system for optimizing the transcoding session is also provided.

System and method for optimizing a communication session between multiple terminals involving transcoding operations

Methods and systems for rate-constrained search ordering algorithms for reducing computational cost of motion estimation in video coding have been provided. Conventional search orderings, such as spiral search, can weaken the filtering criterion of rate-constrained successive elimination algorithms. Simulation results provided herein above demonstrate that, on average, the amount of SAD (sum of absolute differences) operations required to encode the tested sequences, is reduced using embodiments of the invention, when compared to the conventional implementations of spiral search for example. Advantageously, for sequences with unpredictable motion, this reduction may be greater than 5%, and may even exceed 10% when smaller block partitions are evaluated.

Method and system for rate-constrained search ordering

Methods of optimal encoding of signals to be compatible with characteristics of target receivers while meeting constraints pertinent to sizes of encoded signals or capacities of paths communicating signals to the target receivers are disclosed. The methods are based on analytical modeling of the encoding process guided by experimental data relating measured performance indicators of encoded signals of diverse classifications to respective encoding parameters. A computationally-efficient technique is devised to determine optimal encoding parameters based on pre-processed data derived from the analytical models. The methods may be implemented at an encoder of original signals or a transcoder of pre-encoded signals.

Method and apparatus for signal encoding realizing optimal fidelity

In real-time video applications, where unreliable networks are commonplace, corrupted video packets can affect adversely the visual quality. In this patent application, we present an improved method and system for video error correction based on maximum likelihood. Rather than discarding corrupted video packets, the method estimates the likeliest syntactically valid video slice content based on these packets. We present two embodiments, which permits solving the problem at the slice-level, and a simplified solution operating at the syntax element-level. The performance of the method is evaluated using the H.264 baseline profile. Unlike existing video error concealment methods, we correct errors in the bitstream instead of reconstructing missing pixels. Simulation results show that the proposed method yields improved visual quality, and is also computationally simpler than existing state-of-the-art error concealment methods. A corresponding system for video error correction is also provided.

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Brossard, Canada

Stéphane Coulombe