55 results about "Perceptual coding" patented technology

A novel bandwidth extension technique allows information to be encoded and decoded using a fractal self similarity model or an accurate spectral replacement model, or both. Also a multi-band temporal amplitude coding technique, useful as an enhancement to any coding/decoding technique, helps with accurate reconstruction of the temporal envelope and employs a utility filterbank. A perceptual coder using a comodulation masking release model, operating typically with more conventional perceptual coders, makes the perceptual model more accurate and hence increases the efficiency of the overall perceptual coder.

A system provides programming and advertising to a video decoder such as a digital video recorder, computer system, software or hardware player, etc. When a user makes a request to skip a commercial by issuing a command such as 30 second skip forward, alternate media is provided. In some examples, an image advertisement is provided for a predetermined period of time either during the commercial break or when regular programming resumes. In other examples, a substitute commercial is shown. The substitute commercial may be shortened or compressed. The alternate media may be perceptually encoded in a video stream, hidden in a video stream, or provided in a separate stream. In some examples, survey based and neuro-response based data is used to evaluate and select alternate media for particular programming.

A method of modifying the operation of the encoder function and/or the decoder function of a perceptual coding system in accordance with supplemental information, such as a watermark, so that the supplemental information may be detectable in the output of the decoder function. One or more parameters are modulated in the encoder function and/or the decoder function in response to the supplemental information.

The present invention provides an apparatus, method and tangible medium storing instructions for determining tonality of an input audio signal, for selection of corresponding masked thresholds for use in perceptual audio coding. In the various embodiments, the input audio signal is sampled and transformed using a compressed spectral operation to form a compressed spectral representation, such as a cepstral representation. A peak magnitude and an average magnitude of the compressed spectral representation are determined. Depending upon the ratio of peak-to-average magnitudes, a masked threshold is selected having a corresponding degree of tonality, and is used to determine a plurality of quantization levels and a plurality of bit allocations to perceptually encode the input audio signal with a distortion spectrum beneath a level of just noticeable distortion (JND). The invention also includes other methods and variations for selecting substantially tone-like or substantially noise-like masked thresholds for perceptual encoding of the input audio signal.

A perceptual coder is disclosed for encoding image signals, such as speech or music, with different spectral and temporal resolutions for redundancy reduction and irrelevancy reduction. The image signal is initially spectrally shaped using a prefilter. The prefilter output samples are thereafter quantized and coded to minimize the mean square error (MSE) across the spectrum. The disclosed perceptual image coder can use fixed quantizer step-sizes, since spectral shaping is performed by the pre-filter prior to quantization and coding. The disclosed pre-filter and post-filter support the appropriate frequency dependent temporal and spectral resolution for irrelevancy reduction. A filter structure based on a frequency-warping technique is used that allows filter design based on a non-linear frequency scale. The characteristics of the pre-filter may be adapted to the masked thresholds, using techniques known from speech coding, where linear-predictive coefficient (LPC) filter parameters are used to model the spectral envelope of the speech signal. Likewise, the filter coefficients may be efficiently transmitted to the decoder for use by the post-filter using well-established techniques from speech coding, such as an LSP (line spectral pairs) representation, temporal interpolation, or vector quantization.

In a class of embodiments, an audio encoding system (typically, a perceptual encoding system that is configured to generate a single (“unified”) bitstream that is compatible with (i.e., decodable by) a first decoder configured to decode audio data encoded in accordance with a first encoding protocol (e.g., the multichannel Dolby Digital Plus, or DD+, protocol) and a second decoder configured to decode audio data encoded in accordance with a second encoding protocol (e.g., the stereo AAC, HE AAC v1, or HE AAC v2 protocol). The unified bitstream can include both encoded data (e.g., bursts of data) decodable by the first decoder (and ignored by the second decoder) and encoded data (e.g., other bursts of data) decodable by the second decoder (and ignored by the first decoder). In effect, the second encoding format is hidden within the unified bitstream when the bitstream is decoded by the first decoder, and the first encoding format is hidden within the unified bitstream when the bitstream is decoded by the second decoder. The format of the unified bitstream generated in accordance with the invention may eliminate the need for transcoding elements throughout an entire media chain and/or ecosystem. Other aspects of the invention are an encoding method performed by any embodiment of the inventive encoder, a decoding method performed by any embodiment of the inventive decoder, and a computer readable medium (e.g., disc) which stores code for implementing any embodiment of the inventive method.

The invention discloses a compressive perceptual coding and decoding method and a system in a video sensor network, which can achieve high compression ratio and have a good reconstruction effect simultaneously. The method comprises the steps of performing a self-adaptation grouping for original video frames, performing compression perceptual coding measuring for the video frames acquired through the grouping, obtaining an observation vector matrix of each of video frame groups, and performing compressive perceptual decoding reconstruction for the observation vector matrix. Combining a compressive perceptual technique, the method and the system perform measuring, so that reconstruction performance is improved greatly.

The present invention allows video images with improved subjective quality to be transmitted without a concomitant increase in a total number of bits transmitted per frame. Quantization parameters are applied to coefficients of macroblocks within a given video frame. A lower value of quantization parameter is applied near a central region of a video frame. This central region is referred to as a prime video region. Applying a lower quantization parameter to the prime video region has the effect of increasing the bit density within that area thereby improving the video quality. Outside of the prime video region, the bit density is progressively decreased on a macroblock-by-macroblock basis so as to have a zero or near-zero net-gain in bit density over the entire video frame.

A method for digital encoding of an audio stream in which the psychoacoustic modeling bases its computations upon an MDCT for the intensity and a spectral flatness measurement that replaces the phase data for the unpredictability measurement. This dramatically reduces computational overhead while also providing an improvement in objectively measured quality of the encoder output. This also allows for determination of tonal attacks to compute masking effects.

The invention improves HOA sound field representation compression. The HOA representation is analysed for the presence of dominant sound sources and their directions are estimated. Then the HOA representation is decomposed into a number of dominant directional signals and a residual component. This residual component is transformed into the discrete spatial domain in order to obtain general plane wave functions at uniform sampling directions, which are predicted from the dominant directional signals. Finally, the prediction error is transformed back to the HOA domain and represents the residual ambient HOA component for which an order reduction is performed, followed by perceptual encoding of the dominant directional signals and the residual component.

The invention discloses a visual perceptual coding method based on a multi-domain JND (Just Noticeable Difference) model and relates to video information processing. The method comprises the following steps: respectively calculating a space-domain basic JND threshold value, a luminance masking modulation factor, a contrast masking modulation factor and a time domain masking modulation factor of each transformation coefficient in a DCT (Discrete Cosine Transform) block by utilizing a time-space-domain multi-domain JND model so as to obtain the time-space-domain multi-domain JND threshold value of each transformation coefficient; introducing a block perception-based distortion probability evaluative criteria in the transform coding process, and searching a correction factor of each coefficient relative to the JND threshold value through an adaptive searching algorithm so as to obtain a transformation coefficient suppression value; and finally, subtracting the original transformation coefficient from the most appropriate suppression value obtained through corresponding calculation, and taking the coefficient as a novel coefficient to be put at an entropy coding stage. According to the coded suppression strategy of the multi-domain JND model and the block perception-based distortion probability, the coding rate can be effectively reduced on the premise of guaranteeing certain subjective quality, and the compression ratio of the current coding standard is further improved.

The present invention allows higher quality video images to be transmitted without a concomitant increase in a total number of video data bits transmitted per frame. Quantization parameters are applied to coefficients of macroblocks within a given video frame. A lower value of the quantization parameter is applied near a central region of a video frame. This central region is referred to as a prime video region. Applying the lower quantization parameter to the prime video region has the effect of increasing the video data bit density within that area. Outside of the prime video region, the video data bit density per macroblock is decreased so as to have a zero net-gain in bit density over the entire video frame. Furthermore, there may be a plurality of prime video regions where quantization parameters are dynamically coded. In this case, the value of the quantization parameter will increase or decrease within a given prime video region based on a relative importance of a particular prime video region. Consequently, a quantization parameter matrix may vary depending on the video scene.

The invention relates to a multichannel sound signal coding and decoding method and device. The coding method includes: adopting time-frequency transformation to map first multichannel sound signals to be first frequency domain signals, or adopting sub-band filtering to map the first multichannel sound signals to be first sub-band signals; dividing the first frequency domain signals or the first sub-band signals into different time-frequency sub-bands; in each time-frequency sub-band, calculating first statistical characteristics of the first multichannel sound signals; according to the first statistical characteristics, estimating an optimized sub-space mapping model; adopting the optimized sub-space mapping model to map the first multichannel sound signals to be second multichannel sound signals; according to time, frequency and sound channels, performing perceptual coding on at least one group of the second multichannel sound signals and the optimized sub-space mapping model to acquire coded multichannel code stream. In a word, the coding method selects mapping models in a self-adaptive manner, and higher coding efficiency and coding quality can be realized.

The invention relates to a bandwidth extension coding and decoding method and apparatus. The combination of adaptive multiresolution filtering and adaptive time-frequency grid structure and a plurality of linear prediction encoding high-frequency details generates two key technologies, so that the high-frequency part encoding efficiency of digital audio signals and the sound quality of high-frequency part signals can be obviously improved, the low-frequency part of the digital audio signals can still be encoded by means of the traditional perceptual audio coding (for example DRA), and the encoding technology with high subjective sound quality at low bit rate and medium bit rate is realized. In another aspect, an enhancement tool is added on the basis of a current high-quality perceptual coding algorithm such as the DRA, in this way, the downward compatibility with the traditional perceptual coding DRA or other algorithms can be guaranteed. A digital audio encoding and decoding device based on the bandwidth extension coding and decoding method and apparatus can be applied to the fields of satellite HDTV sound accompaniment processing and high-quality audio broadcasting.

A method for stereo audio perceptual encoding of an input signal includes masking threshold estimation and bit allocation. The masking threshold estimation and bit allocation are performed once every two encoding processes. Another method for stereo audio perceptual encoding of an input signal includes performing a time-to-frequency transformation, performing a quantization, performing a bitstream formatting to produce an output stream, and performing a psychoacoustics analysis. The psychoacoustics analysis includes masking threshold estimation on a first of every two successive frames of the input signal.

An apparatus for linear predictive coding of an audio signal comprises a segmentation processor (201) which generates signal segments for the audio signal. An autocorrelation processor (401) for generates a first autocorrelation sequence for each signal segment and a modification processor (403) generates a second autocorrelation sequence for each signal segment by modifying the first autocorrelation sequence in response to at least one psychoacoustic characteristic. A prediction coefficient processor (405) determines linear predictive coding coefficients for each signal segment in response to the second autocorrelation sequence. The invention allows a low complexity linear encoding which takes into account psychoacoustic considerations thereby allowing an improved perceived coding quality for a given data rate.

When compressing an HOA data frame representation, a gain control (15, 151) is applied for each channel signal before it is perceptually encoded (16). The gain values are transferred in a differential manner as side information. However, for starting decoding of such streamed compressed HOA data frame representation absolute gain values are required, which should be coded with a minimum number of bits. For determining such lowest integer number {β e) of bits the HOA data frame representation (C(k)) is rendered in spatial domain to virtual loudspeaker signals lying on a unit sphere, followed by normalisation of the HOA data frame representation (C(k)). Then the lowest integer number of bits is set to (AA).