Dolby Laboratories

About: Dolby Laboratories is a company organization based out in Amsterdam, Netherlands. It is known for research contribution in the topics: Audio signal & Audio signal flow. The organization has 956 authors who have published 1726 publications receiving 29456 citations.

System and method for automatic selection of audio configuration settings

Abstract: In one embodiment the present invention includes a circuit for automatically adjusting an output of an audio device. The circuit includes a memory circuit, a detector circuit, a control circuit, and an output circuit. The memory circuit stores configuration information. The detector circuit detects environment information related to an environment in which the apparatus is present. The control circuit selects selected configuration information from the memory circuit according to the environment information detected by the detector circuit. The output circuit receives an input audio signal and the selected configuration information, modifies the input audio signal according to the selected configuration information, and generates an output audio signal corresponding to the input audio signal as modified according to the selected configuration information.

Audio encoder and decoder with long term prediction

Abstract: The present invention teaches a new audio coding system that can code both general audio and speech signals well at low bit rates. A proposed audio coding system comprises a linear prediction unit for filtering an input signal based on an adaptive filter; a transformation unit for transforming a frame of the filtered input signal into a transform domain; a quantization unit for quantizing a transform domain signal; a long term prediction unit for determining an estimation of the frame of the filtered input signal based on a reconstruction of a previous segment of the filtered input signal; and a transform domain signal combination unit for combining, in the transform domain, the long term prediction estimation and the transformed input signal to generate the transform domain signal.

Joint optimization of scale factors and Huffman code books for MPEG-4 AAC

Abstract: This paper addresses the optimization problem of minimizing the distortion subject to a rate constraint for an MPEG-4 Advanced Audio Coding (AAC) encoder. We first develop a mathematical model of the AAC encoding process. In previous work, the joint optimization problem is modeled as a Viterbi search for a cheapest path through a trellis. This method involves an iteration over a Lagrangian multiplier. We improve on this method by deriving a very accurate guess for the value of the final Lagrangian multiplier of the iteration as a function of the Perceptual Entropy of the signal and the given rate constraint. This reduces the complexity of the Trellis Search significantly. Whereas previous methods including the Trellis Search did not provide optimal solutions to the problem of minimizing the distortion subject to a rate constraint, we establish two methods that for the first time solve this problem optimally. Our first method is based on the formulation and solution of a Mixed Integer Linear Program, whereas our second method uses a Dynamic Programming solution that does not rely on the iteration over a Lagrangian multiplier. Based on our optimal methods, we evaluate the performance of the heuristic Two Loop Search (TLS), which is used in most commercial AAC implementations to solve the problem under consideration, and the performance of the Trellis Search.

Systems and methods for applying adaptive gamma in image processing for high brightness and high dynamic range displays

Abstract: Systems and methods of image processing are provided for a display having a light source modulation layer and a display modulation layer. A section of a perceptual curve, such as a DICOM curve, is extracted for each frame of image data, based on a profile of expected luminance on the display modulation layer from light emitted by the light source modulation layer. The section of the perceptual curve may be used to determine a desired-total response curve which maps display modulation layer input control values to corresponding output luminance values. The desired-total response curve and a display modulator-specific response curve may be applied to image data to generate control values for driving the display modulation layer.

SESQA: semi-supervised learning for speech quality assessment

Abstract: Automatic speech quality assessment is an important, transversal task whose progress is hampered by the scarcity of human annotations, poor generalization to unseen recording conditions, and a lack of flexibility of existing approaches. In this work, we tackle these problems with a semi-supervised learning approach, combining available annotations with programmatically generated data, and using 3 different optimization criteria together with 5 complementary auxiliary tasks. Our results show that such a semi-supervised approach can cut the error of existing methods by more than 36%, while providing additional benefits in terms of reusable features or auxiliary outputs. Improvement is further corroborated with an out-of-sample test showing promising generalization capabilities.