JPH0512802A - Recording and reproducing device for compression-encoding signal - Google Patents

Abstract

PURPOSE:To reduce deterioration in signal quality caused through the repetition of compression and expanding by controlling the frame phase for encoding with the frame phase for duplication as a reference when the compression- encoding signal is duplicated for the purpose of editing, etc. CONSTITUTION:In a frame synchronization detecting part 2, the frame synchronization of a first encoding signal S1 which is reproduced in a reproducing part 1 is detected. In a decoding part 3, the encoding signal S1 is decoded in accordance with this frame synchronization, and a reproducing signal S3 is outputted. In a frame synchronization generating part 4, a second frame synchronization signal is outputted with the detected frame synchronization as a reference and at a timing in which the same sample of the reproduced signal S3 comprises one frame. In an encoding part 5, the reproduced signal S3 is encoded in accordance with this frame synchronization, and a second encoding signal S5 is outputted. The second encoding signal S5 is recorded by a recording part 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression coded signal recording / reproducing apparatus for compressing and coding a signal in frame units for recording and reproducing, and more particularly to a compression coded signal recording / reproducing method for reproducing a compression coded signal. It relates to the device.

[0002]

2. Description of the Related Art In recent years, with the progress and development of coding techniques, techniques for coding digital signals such as voice and images to record and reproduce with high efficiency have been put into practical use. In speech, techniques for constructing frames such as subband coding and transform coding to perform high efficiency coding are being widely applied. Under such circumstances, there are many demands for copying the compression-coded audio signal for the purpose of editing or the like.

A conventional compression coded signal recording / reproducing apparatus for copying such a compression coded signal will be described below.

FIG. 5 is a block diagram of this conventional compression coded signal recording / reproducing apparatus. Here, for encoding and decoding, for example, subband coding is used.
In FIG. 5, the reproduction unit 51 reproduces the first encoded signal S51 from the first recording medium (not shown). The frame synchronization detector 52 detects frame synchronization from the first encoded signal S51 and outputs the first frame synchronization signal S52. The decoding unit 53 decodes the first coded signal S51 according to the first frame synchronization signal S52, and reproduces the reproduced signal S5.
3 is output. The frame synchronization generator 54 outputs the reproduction signal S5.
Count the number of samples that make up one frame from three,
The second frame synchronization signal S54 is output. Encoding unit 5
5 is a reproduction signal S according to the second frame synchronization signal S54
53 is encoded and the second encoded signal S55 is output.
The recording unit 56 records the second encoded signal S55 on a second recording medium (not shown).

FIG. 6A is a timing chart for explaining the operation of this compression-coded signal recording / reproducing apparatus. From the reproduction unit 51, the frames m, m + of the first encoded signal S51
It is assumed that 1, m + 2, ... Are output. The frame synchronization detector 52 detects the synchronization information of each frame and outputs the first frame synchronization signal S52 as shown in the figure. The decoding unit 53 first receives the first frame synchronization signal S52 according to the first frame synchronization signal S52.
The frame m of the encoded signal S51 is decoded and the sample sequence indicated by a of the reproduced signal S53 is output. Frame m +
1, m + 2, ... Are similarly decoded. The frame synchronization generator 54 counts the samples of the reproduction signal S53 and outputs the second frame synchronization signal S54 at the frame cycle. The encoding unit 55 uses the second frame synchronization signal S5.
4, the sample sequence represented by b of the reproduction signal S53 is encoded and output as the frame n of the second encoded signal S55.

[0006]

However, in the above-mentioned conventional configuration, the phase relationship between the first frame synchronization signal S52 and the second frame synchronization signal S54 is equal to the number of samples constituting one frame. Therefore, in many cases, they do not match as shown in the example of FIG. Generally, in the case of performing compression encoding on a frame-by-frame basis, compression is performed by extracting a common parameter from a signal and encoding it within one frame. For example, the maximum level of the signal in the frame is detected as a common parameter, and the samples in the frame are normalized to increase the number of quantization bits and perform compression. At this time, if the phase relationship between the first frame synchronization signal that is a reproduction frame and the second frame synchronization signal that is a recording frame is arbitrary, different sample sequences a as shown in the example of FIG. And the sample sequence b are decoded and encoded respectively. For example, when the common parameter is the maximum level in the frame, as shown in the example of FIG. 6B, the maximum level is different between the sample sequence a and the sample sequence b, and the sample in the frame is different at the maximum level different from the frame m in frame n. Are quantized, resulting in frame n
The part of the sample sequence a in which the sample is quantized is restricted by the coarser quantization of frame m or frame n, and the remaining part of frame n is frame m + 1.
Or frame n, whichever is the coarsest quantization. Therefore, there is a problem that the signal is gradually deteriorated by repeating compression and expansion.

It should be noted that the output of the reproducing section 51 is directly recorded in the recording section 56.
With the configuration for recording in step 2, when an uncorrectable error occurs in the reproducing section 51, processing such as interpolation cannot be performed.

The present invention solves the above-mentioned problems of the prior art. When the coded signal is copied, the coded frame at the time of reproduction and the coded frame at the time of recording are matched with the sample forming the frame. Therefore, it is an object of the present invention to provide a compression-coded signal recording / reproducing device in which deterioration of sound due to repeated compression and expansion is small.

[0009]

To achieve this object, a compression coded signal recording / reproducing apparatus of the present invention comprises a reproducing means for reproducing and outputting a first coded signal from a first recording medium, A frame synchronization detecting means for detecting the frame synchronization of the compression encoding from the first encoded signal and outputting the first frame synchronization signal; and a first synchronization signal inputting the first encoded signal and the first frame synchronization signal. Decoding means for decoding the first coded signal based on the frame synchronization signal of No. 1 as a frame reference and outputting a reproduction signal, and inputting the first frame synchronization signal,
Using this as a time reference, the timing is such that the sample of the reproduced signal that constitutes the encoded frame by encoding becomes the same as the sample of the reproduced signal included in the encoded frame of the first encoded signal. A frame synchronization generating means for outputting a second frame synchronization signal, a reproduction signal and a second frame synchronization signal are inputted, and the reproduction signal is coded with the second frame synchronization signal as a frame reference.
And a recording means for inputting the second coded signal and recording it on the second recording medium.

Further, the compression coded signal recording / reproducing apparatus of the present invention comprises a reproducing means for reproducing and outputting the first coded signal from the first recording medium, and a frame synchronization for compression coding from the first coded signal. Of the first frame synchronization signal and the first frame synchronization signal, and the first coded signal and the first frame synchronization signal are input to the first frame synchronization signal as a frame reference. Decoding means for decoding the encoded signal and outputting a reproduction signal, and the reproduction signal and the first frame synchronization signal are input, the reproduction signal and the first frame synchronization signal are modulated, and a digital audio interface signal is output. And a digital audio interface modulating means for inputting and demodulating the digital audio interface signal to output a recording signal and a third frame synchronization signal. The digital audio interface demodulation means and the third frame synchronization signal are input, and the samples of the recording signal forming the encoded frame by encoding with the time reference as the time reference are within the encoded frame of the first encoded signal. A frame synchronization generating means for outputting a second frame synchronization signal at the same timing as the sample of the reproduced signal included therein, and a recording signal and a second frame synchronization signal are inputted and a second frame synchronization is inputted. It has an encoding means for encoding the recording signal with the signal as a frame reference and outputting the second encoded signal, and a recording means for inputting the second encoded signal and recording it on the second recording medium. .

[0011]

According to the present invention having the above-described structure, the frame synchronization detecting means detects the encoded frame signal at the time of decoding, and the frame synchronization generating means generates the encoded frame signal at the time of encoding based on this signal. Thus, the coded frame synchronization of the decoding means and the coded frame synchronization of the coding means can be matched with the samples forming the frame.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a compression coded signal recording / reproducing apparatus according to a first embodiment of the present invention. In FIG. 1, a reproducing unit 1 reproduces a first encoded signal S1 from a first signal recording medium (not shown). The frame synchronization detector 2 detects frame synchronization from the first encoded signal S1 and outputs a first frame synchronization signal S2.
The decoding unit 3 decodes the first encoded signal S1 according to the first frame synchronization signal S2 and outputs a reproduction signal S3. The frame synchronization generator 4 generates the first frame synchronization signal S
The second frame synchronization signal S4 synchronized with 2 is output.
The encoding unit 5 encodes the reproduction signal S3 according to the frame of the second frame synchronization signal S4, and outputs the second encoded signal S5.
Is output. The recording unit 6 records the second coded signal S5 on a second signal recording medium (not shown).

FIG. 2 is a timing chart for explaining the operation of this compression coded signal recording / reproducing apparatus. Frames m, m + 1, m + of the first encoded signal S1 from the reproduction unit 1
2, ... Is output. The frame synchronization detector 2 detects the synchronization information of each frame to detect the first frame synchronization signal S
2 is output as shown. The decoding unit 3 first decodes the frame m of the first encoded signal S1 according to the first frame synchronization signal S2, and outputs the sample sequence indicated by a of the reproduced signal S3. The frames m + 1, m + 2, ... Are similarly decoded. The frame synchronization generator 4 outputs the second frame synchronization signal S4 at a timing such that the sample sequence indicated by a of the reproduction signal S3 is encoded into one frame with the first frame synchronization signal S2 as a time reference. The encoding unit 5 encodes the sample sequence indicated by a of the reproduction signal S3 according to the second frame synchronization signal S4 and outputs it as the frame n of the second encoded signal S5.

In the example of FIG. 2, since the delay time due to decoding and encoding is one encoded frame, the timings of the first frame synchronization signal S2 and the second frame synchronization signal S4 match, but This timing does not always match depending on the delay time of decoding and encoding.

As described above, according to the present embodiment, the frame synchronization detector 2 detects the coded frame at the time of decoding, and the frame synchronization generator 4 generates the second frame synchronization signal with this signal as a reference. By doing so, the coded frame synchronization of the decoding unit 3 and the coded frame synchronization of the coding unit 5 are made to coincide with the samples forming the frame of the reproduction signal S3, and the sound generated by repeating compression and expansion is reproduced. Can be reduced.

FIG. 3 is a block diagram of a compression coded signal recording / reproducing apparatus according to the second embodiment of the present invention. In FIG. 3, the reproducing unit 1 reproduces the first coded signal S1 from a first signal recording medium (not shown). The frame synchronization detector 2 detects frame synchronization from the first encoded signal S1,
The first frame synchronization signal S2 is output. The decoding unit 3 decodes the first encoded signal S1 according to the first frame synchronization signal S2 and outputs a reproduction signal S3. The digital audio interface modulator 7 receives the reproduction signal S3 and the first frame synchronization signal S2, modulates them, and outputs them as a digital audio interface signal S6. The digital audio interface signal S6 is, for example, a signal of a digital audio interface format defined by IEC958. The digital audio interface demodulation unit 8 inputs the digital audio interface signal S6, demodulates it, and outputs a recording signal S8 and a third frame synchronization signal S7. The frame synchronization generator 4 outputs a second frame synchronization signal S4 synchronized with the third frame synchronization signal S7. The encoding unit 5 encodes the recording signal S8 according to the frame of the second frame synchronization signal S4,
And outputs the encoded signal S5. The recording unit 6 records the second coded signal S5 on a second signal recording medium (not shown). Here, the difference from FIG. 1 is that the reproduction signal S3 and the first frame synchronization signal S2 are modulated into a digital audio interface signal S6 by the digital audio interface modulator 7, and the digital audio interface demodulator 8 demodulates the digital audio interface signal S6. The recording signal S8 and the third frame synchronization signal S7 are demodulated.

FIG. 4 is a timing chart for explaining the operation of this digital audio interface. The frame synchronization detector 2 detects the frame synchronization information of the first coded signal S1 and outputs the first frame synchronization signal S2 as shown in the figure. The decoding unit 3 decodes the first coded signal S1 according to the first frame synchronization signal S2,
A sample sequence represented by D0, D1, D2, ... Of the reproduction signal S3 is output. The digital audio interface modulator 7 modulates a sample of the reproduction signal S3 into a digital audio interface signal S6 as shown in the figure and outputs it. During modulation, the user bit of the first sample D0 at the rising edge of the first frame synchronization signal S2 is set. The digital audio interface demodulation unit 8 demodulates the digital audio interface signal S6 and outputs a third frame synchronization signal S7 from D0, D1, D2, ... And user bits as a recording signal S8. The frame synchronization generator 4 outputs the second frame synchronization signal S4 with the third frame synchronization signal S7 as a time reference. The encoder 5 records the recording signal S according to the second frame synchronization signal S4.
8 is encoded and output as the second encoded signal S5.

As described above, according to the present embodiment, the frame synchronization detector 2 detects the encoded frame signal at the time of decoding, modulates and demodulates this signal by the digital audio interface, and demodulates the third signal. By generating the second frame synchronization signal by the frame synchronization generation unit 4 with the frame synchronization signal S7 as a reference, the encoded frame synchronization of the decoding unit 3 and the encoded frame synchronization of the encoding unit 5 are reproduced. By matching the samples forming the frame, it is possible to reduce the deterioration of sound due to repeated compression and expansion, and to connect a special signal line for transmitting the first frame synchronization signal. Instead, the duplication can be performed by different devices through only the digital audio interface signal.

[0020]

As described above, according to the present invention, the frame synchronization detecting unit detects the encoded frame at the time of decoding, and the frame synchronization generating unit generates the second frame synchronization signal based on this signal. It is possible to reduce the deterioration of sound due to repeated compression and expansion.

Further, according to the present invention, the coded frame signal at the time of decoding is detected by the frame sync detecting section, this signal is modulated and demodulated by the digital audio interface, and the frame is based on the demodulated third frame sync signal. By generating the second frame synchronization signal by the synchronization generation unit, it is possible to reduce the deterioration of sound due to repeated compression and expansion, and
It is possible to perform duplication between different devices via only the digital audio interface signal without connecting a special signal line for transmitting the frame synchronization signal of.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a compression coded signal recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the compressed / encoded signal recording / reproducing apparatus in the first embodiment.

FIG. 3 is a block diagram showing a configuration of a compression coded signal recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a timing chart for explaining the operation of the digital audio interface according to the second embodiment.

FIG. 5 is a block diagram showing a configuration of a conventional compression coded signal recording / reproducing apparatus.

FIG. 6A is a timing chart for explaining the operation of the conventional compressed coded signal recording / reproducing apparatus, and FIG. 6B is a timing chart for explaining the problem of the conventional compression encoded signal recording / reproducing apparatus.

[Explanation of symbols]

1 reproduction section 2 Frame sync detector 3 Decoding section 4 frame synchronization generator 5 Encoding section 6 recording section 7 Digital audio interface modulator 8 Digital audio interface demodulator

Claims (2)

[Claims] 1. A compression-coded signal recording / reproducing apparatus for compression-encoding a signal on a frame-by-frame basis to record and reproduce the same on a recording medium, wherein the first encoded signal is reproduced and output. Reproducing means; frame synchronization detecting means for detecting the frame synchronization of compression encoding from the first encoded signal and outputting a first frame synchronizing signal; the first encoded signal and the first frame And a decoding means for decoding the first coded signal with the first frame synchronization signal as a frame reference and outputting a reproduction signal, and inputting the first frame synchronization signal. With this as a time reference, the sample of the reproduction signal which forms the encoded frame by encoding is the sample of the reproduction signal included in the encoded frame of the first encoded signal, and A frame synchronization generating unit that outputs a second frame synchronization signal at a timing such that the reproduction signal and the second frame synchronization signal are input, and the second frame synchronization signal is used as a frame reference. Compressed coded signal including coding means for coding the reproduced signal and outputting the second coded signal, and recording means for inputting the second coded signal and recording it on the second recording medium Recording / playback device. 2. A compression-coded signal recording / reproducing apparatus for compression-encoding a signal in units of frames to record and reproduce it on a recording medium, wherein the first encoded signal is reproduced and outputted from the first recording medium. Reproducing means; frame synchronization detecting means for detecting the frame synchronization of compression encoding from the first encoded signal and outputting a first frame synchronizing signal; the first encoded signal and the first frame A decoding means for inputting a synchronization signal, decoding the first encoded signal with the first frame synchronization signal as a frame reference, and outputting a reproduction signal; and the reproduction signal and the first frame synchronization. A digital audio interface modulating means for inputting a signal, modulating the reproduction signal and the first frame synchronization signal, and outputting a digital audio interface signal; Digital audio interface demodulation means for inputting a digital audio interface signal, demodulating the digital audio interface signal and outputting a recording signal and a third frame synchronizing signal, and a code for inputting the third frame synchronizing signal as a time reference The second frame at a timing such that the sample of the recording signal that forms the encoded frame by encoding becomes the same as the sample of the reproduction signal included in the encoded frame of the first encoded signal. A frame synchronization generating means for outputting a synchronization signal, the recording signal, and the second frame synchronization signal are input, and the recording signal is encoded with the second frame synchronization signal as a frame reference, and the second encoding is performed. An encoding unit that outputs a signal; and a recording unit that inputs the second encoded signal and records the second encoded signal on a second recording medium. A compression coded signal recording / reproducing apparatus provided.