Fast frame optimization in an audio encoder
    12.
    发明授权
    Fast frame optimization in an audio encoder 有权
    音频编码器中的快速帧优化

    公开(公告)号:US06952677B1

    公开(公告)日:2005-10-04

    申请号:US09673463

    申请日:1998-04-15

    CPC classification number: G10L19/002

    Abstract: In a transform encoder for audio data, encoded data in the form of mantissas, exponents and coupling data is packed into fixed length frames in an output bitstream. The fields within the frame for carrying the different forms of data are variable in length, and apace within the frame must be allocated between them to fit all of the required information into the frame. The space required by the various data types depends on certain encoding parameters, which are calculated for a particular frame before the data is encoded, thus ensuring that the encoded data will fit into the frame before the computationally expensive encoding process is carried out. Information in relation to, for example, transform length, coupling parameters and exponent strategy are determined, which allows the space required for the coupling and exponent data to be calculated. The mantissa encoding parameters can then be iteratively determined so that the encoded mantissas will fit into the frame with the other encoded data. The determined encoding parameters are stored and the audio data is encoded according to those parameters after it has been determined that the encoded data will fit into the frame.

    Abstract translation: 在用于音频数据的变换编码器中,尾数形式的编码数据,指数和耦合数据被打包到输出比特流中的固定长度帧中。 用于承载不同形式数据的帧内的字段的长度是可变的,并且帧内的间隔必须在它们之间分配以将所有所需的信息适配到帧中。 各种数据类型所需的空间取决于在数据被编码之前针对特定帧计算的某些编码参数,从而确保在执行计算昂贵的编码处理之前编码的数据将适合于帧。 确定与例如变换长度,耦合参数和指数策略相关的信息,这允许计算耦合所需的空间和指数数据。 然后可以迭代地确定尾数编码参数,使得编码尾数将与其他编码数据拟合到帧中。 存储确定的编码参数,并且在确定编码数据将适合于帧之后,根据这些参数来编码音频数据。

    Multi-precision technique for digital audio encoder
    13.
    发明授权
    Multi-precision technique for digital audio encoder 有权
    数字音频编码器的多精度技术

    公开(公告)号:US07680671B2

    公开(公告)日:2010-03-16

    申请号:US11530313

    申请日:2006-09-08

    CPC classification number: G10L19/0212 G10L19/16

    Abstract: AC-3 is a high quality audio compression format widely used in feature films and, more recently, on Digital Versatile Disks (DVD). For consumer applications the algorithm is usually coded into the firmware of a DSP Processor, which due to cost considerations may be capable of only fixed point arithmetic. It is generally assumed that 16-bit processing is incapable of delivering the high fidelity audio, expected from the AC-3 technology. Double precision computation can be utilized on such processors to provide the high quality; but the computational burden of such implementation will be beyond the capacity of the processor to enable real-time operation. Through extensive simulation study of a high quality AC-3 encoder implementation, a multi-precision technique for each processing block is presented whereby the quality of the encoder on a 16-bit processor matches the single precision 24-bit implementation very closely without excessive additional computational complexity.

    Abstract translation: AC-3是一种高质量的音频压缩格式,广泛应用于影片以及最近的数字多功能磁盘(DVD)上。 对于消费者应用,算法通常被编码到DSP处理器的固件中,由于成本考虑可能仅能够进行固定点算术。 通常假设16位处理不能提供来自AC-3技术的高保真音频。 这种处理器可以利用双精度计算来提供高品质; 但是这种实现的计算负担将超出处理器启用实时操作的能力。 通过对高品质AC-3编码器实现的广泛的仿真研究,提出了一种用于每个处理块的多精度技术,其中16位处理器上的编码器的质量非常接近单精度24位实现,而不需要额外的附加 计算复杂度。

    Fast modified discrete cosine transform method
    15.
    发明授权
    Fast modified discrete cosine transform method 有权
    快速修正离散余弦变换法

    公开(公告)号:US07203717B1

    公开(公告)日:2007-04-10

    申请号:US10129046

    申请日:1999-10-30

    CPC classification number: G06F17/142

    Abstract: A technique for computationally efficient evaluation of the Modified Discrete Cosine Transform (MDCT) using the Fast Fourier Transform (FFT) method is presented in which the input of the FFT block consists of a sequence of N complex numbers, and this complex data is evaluated using an N/2-Point FFT only, thereby descreasing computation burden almost by two.

    Abstract translation: 提出了一种使用快速傅里叶变换(FFT)方法对修正离散余弦变换(MDCT)进行计算有效评估的技术,其中FFT块的输入由N个复数序列组成,该复数数据使用 只有N / 2点FFT,从而使计算负担几乎降低2。

    Universal sampling rate converter for digital audio frequencies
    16.
    发明授权
    Universal sampling rate converter for digital audio frequencies 有权
    数字音频通用采样率转换器

    公开(公告)号:US07177812B1

    公开(公告)日:2007-02-13

    申请号:US10312205

    申请日:2000-06-23

    CPC classification number: H03H17/0642

    Abstract: A method for conversion of input audio frequency data, at an input sample frequency, to output audio frequency data, at an output sample frequency. The input data is subjected to expansion to produce expanded data at an output sample frequency. The expanded data is interpolated to produce output data. In one embodiment of the invention the interpolation is effected by a process that also filters the output data. In another embodiment, the input data is sampled by an integer factor to produce expanded data, the expanded data is then interpolated to produce the output data. Also disclosed is a method of transition of a signal output, at one frequency, to a signal output at another frequency. The signal output at said one frequency is faded out over a period, and the signal output at said other frequency is faded in over that period. Both signal outputs are combined to produce the signal output over said period. Apparatus for effecting the methods is also disclosed.

    Abstract translation: 一种在输入采样频率下以输入采样频率转换输入音频数据以输出音频数据的方法。 对输入数据进行扩展,以输出采样频率产生扩展数据。 扩展的数据被内插以产生输出数据。 在本发明的一个实施例中,内插是通过也对输出数据进行过滤的过程实现的。 在另一个实施例中,以整数因子对输入数据进行采样以产生扩展数据,然后内插扩展数据以产生输出数据。 还公开了一种将一个频率的信号输出转换成另一频率的信号输出的方法。 在所述一个频率处的信号输出在一段时间内消失,并且在该周期内以所述另一频率输出的信号衰减。 两个信号输出被组合以产生在所述周期上的信号输出。 还公开了用于实现该方法的装置。

    Multi-precision technique for digital audio encoder
    17.
    发明授权
    Multi-precision technique for digital audio encoder 有权
    数字音频编码器的多精度技术

    公开(公告)号:US07117053B1

    公开(公告)日:2006-10-03

    申请号:US09830441

    申请日:1998-10-26

    CPC classification number: G10L19/0212 G10L19/16

    Abstract: AC-3 is a high quality audio compression format widely used in feature films and, more recently, on Digital Versatile Disks (DVD). For consumer applications the algorithm is usually coded into the firmware of a DSP Processor, which due to cost considerations may be capable of only fixed point arithmetic. Commercial AC-3 Encoders have been successfully implemented on 20-bit and 24-bit word-length processors. However, it is generally assumed that 16-bit processing is incapable of delivering the high fidelity audio, expected from the AC-3 technology. Double precision computation can be utilised on such processors to provide the high quality; but the computational burden of such implementation will be beyond the capacity of the processor to enable real-time operation. Through extensive simulation study of a high quality AC-3 Encoder implementation, a multi-precision technique for each processing block is presented whereby the quality of the encoder on a 16-bit processor matches the single precision 24-bit implementation very closely without excessive additional computational complexity.

    Abstract translation: AC-3是一种高质量的音频压缩格式,广泛应用于影片以及最近的数字多功能磁盘(DVD)上。 对于消费者应用,算法通常被编码到DSP处理器的固件中,由于成本考虑可能仅能够进行固定点算术。 商用AC-3编码器已经在20位和24位字长处理器上成功实现。 然而,通常假设16位处理不能提供来自AC-3技术的高保真音频。 这种处理器可以利用双精度计算来提供高品质; 但是这种实现的计算负担将超出处理器启用实时操作的能力。 通过对高品质AC-3编码器实现的广泛的仿真研究,提出了一种用于每个处理块的多精度技术,其中16位处理器上的编码器的质量非常接近单精度24位实现,而不会过多的附加 计算复杂度。

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