JPH06348295A - Voice band dividing and decoding device - Google Patents

Abstract

PURPOSE:To add an equalizer function with a simple constitution by providing an adjustment means between an inverse quantization processing circuit and a synthetic filtering circuit and employing the features of a voice band dividing and coding system. CONSTITUTION:The device is provided with an adjustment means (gain varying circuits) 16 which are placed between an inverse quantization processing circuit 12 and a synthetic filtering circuit 14 and adjust the size of the voice data for every band outputted by the circuit 12. The circuit 16 is provided for every band and is controlled by the signal from a tone quality operation panel 18. When a user operates the panel to emphasize higher frequencies, the circuit 16 of a higher band increases the voice level. If the user operates the panel to attenuate middle frequencies, the circuit 16 of the middle band lowers the voice level. Thus, by only providing gain varying circuits 16 in a conventional voice band dividing and decoding device, voice frequencies for every band are compensated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice band division decoding device. In particular, the present invention relates to an audio decoding LSI for an MPEG standard compliant player that expresses a decompressed moving image and decompressed audio synchronously based on compressed moving image data and compressed audio data in a moving image karaoke, CD-I moving image player and the like.

[0002]

2. Description of the Related Art As a coding method for band-compressing a voice signal, voice band division coding has been well known. For example, an example is shown in JP-A-3-248376 (G11B20 / 18). In this voice band division encoding, a voice signal is divided into a plurality of bands and compressed, and the compressed data is multiplexed and transmitted.

In the voice band division decoding device, the received voice data is decoded into a plurality of bands of voice data, which is then synthesized by the synthesis filter circuit to restore the original voice signal. Meanwhile, some audio devices have an equalizer function for adjusting the sound quality according to the preference of the user.

[0004]

The present application is to add this equalizer function to a voice band division decoding apparatus. In particular, the present application adds the equalizer function with a simple configuration by utilizing the characteristics of the voice band division coding method.

[0005]

A speech band division decoding apparatus according to the present invention comprises an inverse quantization processing circuit (12) and a synthesis filter circuit.
An adjusting means (16) provided between the inverse quantization processing circuit (12) and the inverse quantization processing circuit (12) for adjusting the size of the audio data for each band.
It is characterized by including.

[0006]

According to the present invention, of the audio signals from the inverse quantization processing circuit (12), the level of the audio data in a desired frequency band is changed by the adjusting means (16), so that the synthesis filter circuit
Adjust the frequency characteristics of the audio signal output from (14).

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. (12) is an inverse quantization circuit. Inverse quantization circuit (12)
Inputs voice band division encoded data and outputs voice data for each band. Here, in order to simplify the explanation, there are three bands of a high band, a middle band, and a low band.

(14) is a synthesis filter circuit. (16) (1
6) and (16) are the variable gain circuit which is the feature of the present application. The gain variable circuit (16) is provided for each band and is controlled by a signal from the sound quality operation panel (18). In other words, when the user performs an operation that emphasizes high frequencies,
The high-frequency gain variable circuit (16) raises the audio level. Further, when the user performs an operation of attenuating the mid-range, the mid-range gain variable circuit (16) lowers the audio level.

As described above, in this embodiment, the voice frequency can be corrected for each band only by providing the gain variable circuit (16) in the conventional voice band division decoding apparatus. Although the number of bands is three in the present embodiment, the present invention is not limited to this. Further, the gain variable circuit (16) of the present embodiment
Can adjust the level, but this may be such that the output of audio data is turned on / off to cut a specific frequency band.

Further, if the dequantization circuit (12) includes the range information indicating the loudness of the sound data in each empty band, the range information may be replaced.
Further, the size of the audio waveform data in the audio data may be variable.

[0011]

The adjusting means (16) of the present invention is provided between the inverse quantization processing circuit (12) and the synthesis filter circuit (14).
For this reason, in the equalizer processing of separating the sound into bands for adjusting the frequency characteristic, adjusting the level, and synthesizing again, except for the level adjustment, the same processing as that of the audio band division decoding processing is performed, so that the circuit can be simplified. Can be achieved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

[Explanation of symbols]

 12 ... Inverse quantization processing circuit. 14 ... Band synthesis filter circuit, 16 ... Gain variable circuit (adjusting means).

Claims (2)

[Claims] 1. A speech band division decoding device comprising an inverse quantization processing circuit (12) and a synthesis filter circuit (14) for synthesizing speech data for each band from the inverse quantization processing circuit (12). An adjusting means (16) provided between the inverse quantization processing circuit (12) and the synthesis filter circuit (14) for adjusting the size of the audio data for each band from the inverse quantization processing circuit (12). ). A voice band division decoding device comprising: 2. The adjusting means (16) sets the size of audio data in a desired band to zero.
Voice band division decoding device.