摘要:
A parametric coding method and apparatus are provided for coding a multichannel digital audio signal. The method includes a coding step for coding a signal from a channel reduction matrixing of the multichannel signal. The coding method also includes: obtaining, for each frame of predetermined length, spatial information parameters of the multichannel signal; dividing the spatial information parameters into a plurality of blocks of parameters; selecting a block of parameters as a function of the index of the current frame; and coding the block of parameters selected for the current frame.
摘要:
A method and apparatus for the parametric encoding of a stereo digital-audio signal. The method includes encoding a mono signal produced by downmixing applied to the stereo signal and encoding spatialisation information of the stereo signal. Downmixing includes determining, for a predetermined set of frequency sub-bands, a phase difference between two stereo channels; obtaining an intermediate channel by rotating a first predetermined channel of the stereo signal through an angle obtained by reducing the phase difference; determining the phase of the mono signal from the phase of the signal that is the sum of the intermediate channel and the second stereo signal, and from a phase difference between, on the one hand, the signal that is the sum of the intermediate channel and the second channel and, on the other hand, the second channel of the stereo signal. Also provided are a decoding method, an encoder and a decoder.
摘要:
A parametric coding method and apparatus are provided for coding a multichannel digital audio signal. The method includes a coding step for coding a signal from a channel reduction matrixing of the multichannel signal. The coding method also includes: obtaining, for each frame of predetermined length, spatial information parameters of the multichannel signal; dividing the spatial information parameters into a plurality of blocks of parameters; selecting a block of parameters as a function of the index of the current frame; and coding the block of parameters selected for the current frame.
摘要:
A method and apparatus for the parametric encoding of a stereo digital-audio signal. The method includes encoding a mono signal produced by downmixing applied to the stereo signal and encoding spatialization information of the stereo signal. Downmixing includes determining, for a predetermined set of frequency sub-bands, a phase difference between two stereo channels; obtaining an intermediate channel by rotating a first predetermined channel of the stereo signal through an angle obtained by reducing the phase difference; determining the phase of the mono signal from the phase of the signal that is the sum of the intermediate channel and the second stereo signal, and from a phase difference between, on the one hand, the signal that is the sum of the intermediate channel and the second channel and, on the other hand, the second channel of the stereo signal. Also provided are a decoding method, an encoder and a decoder.
摘要:
A method and decoder are provided for parametrically decoding a stereo digital audio signal. The method includes synthesizing the stereo signal, per frequency sub-band, on the basis of a decoded mono signal ({circumflex over (M)}[j]), arising from a downmix of the stereo signal and from spatial information parameters of the stereo signal, in such a way that the signals obtained have the following form: L ^ [ j ] = c 1 [ j ] · M ^ 1 [ j ] R ^ [ j ] = c 2 [ j ] · M ^ 2 [ j ] , with {circumflex over (L)}[j] and {circumflex over (R)}[j] being channels of the synthesized signal, {circumflex over (M)}1[j] and {circumflex over (M)}2[j] being signals that are a function of the decoded mono signal and c1[j], c2[j] being gains, wherein the gains are calculated as follows: c 1 [ j ] = 2 I ^ [ j ] I ^ [ j ] + 1 c 2 [ j ] = 2 I ^ [ j ] + 1 with Î[j] being an amplitude ratio between the two channels of the stereo signal, obtained from the decoded parameters.
摘要翻译:提供了一种用于对立体声数字音频信号进行参数解码的方法和解码器。 该方法包括:基于由立体声信号的下混合产生的解码单声道信号({回旋(M)} [j]),从每个频率子带合成立体声信号,并根据 立体声信号,使得获得的信号具有以下形式:L ^ [j] = c 1 [j]·M ^ 1 [j] R ^ [j] = c 2 [j] (M)} 1 [j]中的{回旋(L)} [j]和{convflex over(R)} [j]是合成信号的通道, 2(j)是作为解码单声道信号的函数的信号,c1 [j],c2 [j]是增益,其中增益计算如下:c 1 [j] = [j] + 1 c 2 [j] = 2 I ^ [j] + 1,其中Î[j]是立体声信号的两个声道之间的振幅比, 从解码参数获得。
摘要:
The invention relates to an arithmetic encoding by bit planes (MSB, . . . , LSB), that comprises using tables of probability to have a 0 or 1 bit for encoding each bit plane. According to an embodiment of the invention, the probability tables are calculated dynamically for each signal frame based on a probability density model (Mod) corresponding to the distribution (H) of the signal (X) on each frame.