JP2677054B2 - Coded signal duplication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coded signal copying apparatus for copying a coded signal having a frame from a first recording medium to a second recording medium.

[0002]

2. Description of the Related Art A conventional coded signal duplicating apparatus will be described below.

First, the structure of the encoded signal will be described with reference to FIG. Encoded signal is divided into multiple sub-bands
Signal separated by frames with a certain time interval
Is a band-division coded signal for coding. Bandwidth
The split coding is, for example, BB Review Tech.
Nical (EBU REVIEW TECHNICAL)
Issue 230, pages 71-94, August 1988
Represented "Low bit rate code of high quality audio signal
Introduction of the MASCAM system ”(LOWBIT-R
ATE CODING OF HIGH-QUALIT
Y AUDIO SIGNALS AN INTROD
UCTION TO THE MASCAM SYSTEM
EM). In FIG. 5, the first 501 is frame synchronization information indicating frame synchronization. 502 is allocation information indicating the number of allocated bits of the level information of each partial band. Reference numeral 503 is level information indicating the maximum signal level of the absolute value of the signal in the frame for each partial band. Reference numeral 504 is sample data in which a signal of each partial band in the frame is normalized using the level information 503 and data quantized according to the number of allocated bits represented by the allocation information 502 is arranged in each partial band order. Here, if the allocation information 502 is all "0", bits are not assigned to all partial bands, so that the sample data is not used for decoding and the reproduced signal is silent.

FIG. 4 is a block diagram of this conventional coded signal duplicating apparatus. In FIG. 4, 401 is a reproducing means, 402 is a decoding means, 403 is an encoding means, and 404 is a recording means.

The operation of the coded signal duplicating apparatus configured as described above will be described below.

First, the reproduction means 401 reproduces and outputs the reproduction coded signal 405 having the structure shown in FIG. 5 from the first recording medium. The decoding means 402 receives the reproduced coded signal 405, dequantizes the sample data according to the allocation information in the frame, and outputs the reproduced signal 406 using the level information. The encoding means 403 inputs the reproduced signal 406, obtains level information 503 representing the maximum signal level of each sub-band in the frame, normalizes each sub-band signal using this, and determines each sub-band according to the allocation information. The quantized sample data is obtained, and the recording coded signal 40 having the configuration of FIG.
7 is output. The recording means 404 records the encoded signal 407.
Is recorded on the second recording medium.

[0007]

However, in the above conventional configuration, the reproduction coded signal 4 by the reproduction means 401 is used.
When an uncorrectable error occurs in the allocation information 402 of the reproduction coded signal 405 at the time of outputting 05, the recorded coded signal 407 having the erroneous allocation information is the second
It is recorded and reproduced on the recording medium of. If the allocation information is incorrect, correct sample data cannot be cut out. During reproduction of the duplicate encoded signal on the second recording medium, the sample data of each partial band in the frame cut out by this erroneous allocation information is dequantized and reproduced, so that this portion is abnormal. Therefore, there is a problem that the sound quality of the reproduced signal deteriorates.

Further, once the reproduced coded signal 405 is decoded by the decoding means 402, a reproduced signal 406 is outputted,
Since the recording coded signal 407 is obtained by encoding the reproduction signal 406 by the encoding means 403, the encoding means 403 performs the encoding every time the copying is repeated, so that an error occurs and the sound quality of the recording encoded signal is improved. It had a problem of deterioration.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a coded signal duplicating apparatus for reducing deterioration of sound quality due to duplication of a recorded coded signal.

[0010]

In order to achieve this object, a coded signal duplicating apparatus of the present invention comprises a delay means for delaying a reproduction coded signal for a predetermined time and outputting a delay coded signal, and a reproduction coding. Frame synchronization information detecting means for detecting frame synchronization of the signal and outputting a frame synchronization detection signal;
Allocation information position prediction means for outputting an allocation information position prediction signal for predicting the position of allocation information indicating a data array in the reproduction coded signal from the frame synchronization detection signal, and allocation information from the allocation information position prediction signal and an error flag If there is an allocation error from the allocation error signal and the delayed encoded signal, the allocation error determination means that outputs an allocation error signal that indicates that there is an error in the corresponding frame will be silenced when the encoded signal is reproduced. Of the allocation information is rewritten so as to indicate that there is no data.

[0011]

According to the present invention, the frame synchronization information detecting means outputs the frame synchronization detecting signal from the reproduced coded signal, and the allocation information position predicting means outputs the allocation information position predicting signal from the frame synchronization detecting signal. The allocation error determining means outputs an allocation error signal indicating that there is an error in the allocation information from the allocation information position prediction signal and the error flag, and the encoded signal muting means allocates the allocation error signal and the delayed encoded signal when an allocation error occurs. By rewriting the information so as to indicate that there is no data, a recording coded signal is output so that the corresponding frame becomes silent during reproduction and decoding.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a coded signal duplicating apparatus according to an embodiment of the present invention. In FIG. 1, 101 is a reproducing means for outputting a reproduction coded signal 108 from the first recording medium and an error flag 109 indicating that there is an uncorrectable error during reproduction. 102 is a reproduction coded signal 10
8 is a delay unit that inputs 8 and outputs a delay encoded signal 111. Reference numeral 103 is a frame synchronization information detecting means for inputting the reproduction coded signal 108 and outputting a frame synchronization detection signal 110. An allocation information position predictor 104 receives the frame synchronization detection signal 110 and outputs an allocation information position prediction signal 112. 106 is an allocation information position prediction signal 112 and an error flag 109
Is an allocation error determining means for inputting an input and outputting an allocation error signal 113. Reference numeral 105 denotes a coded signal mute means for inputting the delay coded signal 111 and the allocation error signal 113 and outputting a record coded signal 114. Reference numeral 107 denotes a recording unit that inputs the recording coded signal 114 and records it on the second recording medium.

FIG. 2 is a detailed block diagram of the coded signal duplicating apparatus according to the embodiment of the present invention. In FIG. 2, 201 is a reproduction coded signal 2 from the first recording medium.
10 and an error flag 211 indicating that an error has occurred during reproduction. Reference numeral 202 denotes a first delay device which inputs the reproduction coded signal 210 and outputs the delay coded signal 214. Reference numeral 203 denotes a frame synchronization information detector which receives the reproduction coded signal 210 and outputs a frame synchronization detection signal 212. 204 receives the frame synchronization detection signal 212 and inputs allocation information position prediction signal 213
Is an allocation information position predictor that outputs 20
5 receives the allocation information position prediction signal 213 and the error flag 211 and receives the allocation error detection signal 21.
It is an allocation error detector that outputs 5. 20
A second delay unit 6 receives the allocation information position prediction signal 213 and outputs a delayed allocation information position prediction signal 216. Reference numeral 208 denotes an allocation error detection signal 215 and a delayed allocation information position prediction signal 21.
6 is an allocation error signal generator that inputs 6 and outputs an allocation error signal 217. A coded signal mute unit 207 receives the delay coded signal 214 and the allocation error signal 217 and outputs a record coded signal 218. Reference numeral 209 is a recorder for inputting the recording coded signal 218 and recording it on the second recording medium.

In FIG. 2, 201-204, 207,
Reference numeral 208 is the same component as 101 to 104, 105, 107 in FIG. 1, and the allocation error detector 205, the second delay unit 206, and the allocation error signal generator 208 in FIG. 2 determine the allocation error in FIG. 4 shows a detailed configuration of the means 106.

The operation of the coded signal duplicating apparatus of this embodiment having the above-mentioned configuration will be described below with reference to FIG.

First, the reproducer 201 outputs a reproduction coded signal 210 and an error flag 211 indicating that there is an uncorrectable error during reproduction from the reproduction signal of the first recording medium (not shown). The first delay unit 202 delays the reproduction coded signal 210 of the regenerator 201 by time τ and outputs a delay coded signal 214. The frame synchronization information detector 203 detects the frame synchronization information 501 from the reproduction coded signal 210 of the reproduction device 201 and outputs the frame synchronization detection signal 212. The allocation information position predictor 204 outputs an allocation information position prediction signal 213 for predicting the position of allocation information indicating a data array in the reproduction coded signal 210 from the frame sync detection signal 212 of the frame sync detector 203. The allocation error detector 205 receives the error flag 211 of the regenerator 201 and the allocation information position prediction signal 213 of the allocation information position predictor 204 as input, and makes an error during the period when the allocation information position prediction signal 213 predicts that the allocation information is allocation information. When the flag 211 becomes "H", the allocation error detection signal 215 indicating that there is an error in the allocation information of the reproduction coded signal 210 becomes "H", and the next allocation information position prediction signal 2
It is reset to "L" at the rising edge of 13. The second delay unit 206 delays the allocation information position prediction signal 213 of the allocation information position predictor 205 by the same time τ as the delay coded signal 214 and outputs a delayed allocation information position prediction signal 216. The allocation error signal generator 208 is the allocation error detector 2
05 allocation error detection signal 215 and second delay device 206 delayed allocation information position prediction signal 21
6 is input, and delayed allocation information position prediction signal 21
6 the allocation error detection signal 215 in the period predicted as the allocation information of the delay coded signal 214.
Is "H", the allocation error signal 217 is "H", and if the allocation error detection signal 215 signal is "L", the allocation error signal 217 is "L".
become. The encoded signal mute unit 207 is the first delay unit 2
02 delay-coded signal 214 of 02 and allocation error signal 217 of allocation error signal generator 208 are input. When allocation error signal 217 is "H", the reproduction signal is generated when all the corresponding frames of allocation information 402 are reproduced and output. The recorded coded signal 21 is rewritten to "0" indicating that there is no data so as to be silent.
8 is output. The recorder 209 is an encoded signal mute device 2
The recording coded signal 218 of 08 is recorded on the second recording medium (not shown).

As described above, according to this embodiment, the first delay unit (202) that outputs the delayed encoded signal 214, the frame synchronization information detector (203) that outputs the frame synchronization detection signal 212, Allocation information position prediction signal 21 for predicting the position of allocation information 502
Allocation information position predictor for outputting 3 (204)
An allocation error detector (205) that outputs an allocation error detection signal 215 indicating that the allocation information 502 has an error, and a second delay device (206) that outputs a delayed allocation information position prediction signal 216. An allocation error signal generator (208) that outputs an allocation error signal 217, and is applicable when reproducing a coded signal that is duplicated by rewriting all allocation information 502 to "0" when the allocation error signal 217 is "H". In the case where there is an uncorrectable error in the allocation information at the time of reproducing the reproduced coded signal 210 by the reproducer 201, by providing the coded signal mute device (207) which outputs the recorded coded signal so that the frame becomes silent. Write all allocation information to "0" Since the bits are not assigned to each partial band when the corresponding frame is played back, the sample data is not used for decoding and the playback signal becomes silent and does not appear in the playback signal as an abnormal sound. It is possible to reduce deterioration of sound quality.

[0019]

As described above, according to the present invention, the allocation information is rewritten from the allocation error signal and the delay coded signal so as to indicate that there is no data at the time of allocation error, so that the corresponding frame can be reproduced at the reproduction coded signal reproduction. By providing the coded signal mute means for outputting the recorded coded signal so that the sound becomes silent, the coded signal duplicating apparatus can be realized with a simple structure without using the decoding means and the coding means. Since the encoding means is not used, the encoded signal is duplicated and recorded from the first recording medium to the second recording medium, so that the sound quality is deteriorated by decoding, quantization in encoding, and quantization error in dequantization. Can be prevented. Also, in the event of an allocation error, the allocation information is updated to indicate that there is no data instead of incorrect allocation information, so that when the corresponding frame is reproduced and output, the reproduced signal is silenced and no abnormal noise is generated. Therefore, it is possible to reduce the deterioration of the sound quality when the encoded signal is copied.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a coded signal duplicating apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a coded signal duplicating apparatus in the embodiment.

FIG. 3 is a signal timing chart showing the operation of the coded signal duplicating apparatus in the embodiment.

FIG. 4 is a block diagram showing a configuration of a conventional coded signal duplication device.

FIG. 5 is a schematic diagram showing a configuration of a coded signal used in a conventional coded signal duplication device.

[Explanation of symbols]

 101 reproducing means 102 delay means 103 frame synchronization information detecting means 104 allocation information position predicting means 105 allocation error determining means 106 encoded signal muting means 107 recording means

Claims (1)

(57) [Claims] 1. A coded signal reproducing means for reproducing a reproduction coded signal from a first recording medium and outputting an error flag indicating an uncorrectable error during reproduction, and delaying the reproduction coded signal for a predetermined time. A delay means for outputting a delay encoded signal; a frame synchronization information detecting means for detecting frame synchronization information of the reproduction encoded signal and outputting a frame synchronization detection signal; The allocation information position prediction means for outputting the allocation information position prediction signal for predicting the position of the allocation information indicating the data array of, and the allocation information position prediction signal and the error flag indicate that there is an error in the allocation information. Allocation error determining means for outputting an allocation error signal indicating the allocation error, If the allocation error signal and the delayed coded signal cause an allocation error, the allocation information is rewritten so as to indicate that there is no data so that the corresponding frame becomes silent when the duplicated coded signal is reproduced. A coded signal duplicating apparatus comprising: a coded signal mute means for outputting a record coded signal; and a recording means for recording the record coded signal on a second recording medium.