JPH09311695A - Quick reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quick reproducing device by which an excellent reproduction result can be obtained when a quick reproduction is carried out. SOLUTION: The subject device, in which a coded data stored in a semiconductor memory 10 by a frame unit, which is a predetermined time length, is decoded and a quick reproduction is carried out, is provided with a main control circuit 8, by which the coded data stored in the semiconductor memory 10 is read every predetermined frame interval in the case of quick feed reproduction, time base compression is carried out by using the read coded data of the first frame and the coded data of the second, the third, and the fourth frames following the first frame, and reproduction is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fast-forward reproduction device.

[0002]

2. Description of the Related Art As a conventional fast-forward reproducing apparatus, Japanese Patent Application Laid-Open No. 63-63
A high-speed fast-forward reproduction device described in Japanese Patent Publication No. 254000 is known. This playback device uses ADPCM (Adaptive D
The fast-forward reproduction processing is realized by reading and reproducing coded data which is coded for each frame (250 ms) by skipping a predetermined number of frames by the ifferential Pulse Code Modulation) method.

[0003]

However, in the above-described conventional fast-forward reproducing apparatus, when the fast-forwarding speed is about 2 to 4 times that of the normal reproduction, the frame is skipped and the reproducing process is performed. There are many parts that cannot be heard due to missing audio data.

When the fast-forward speed is increased to about 20 times to perform fast-forward playback at high speed, the phrase to be played is considerably fragmented, so that the silent section is not reproduced and the device is stopped at the position where the user wants to stop. There is a problem that it cannot be done.

The fast-forward reproducing apparatus of the present invention has been made in view of such problems, and an object thereof is to provide a fast-forward reproducing apparatus which can obtain a good reproduction result even when performing fast-forward reproduction. Especially.

[0006]

In order to achieve the above object, a fast-forward reproducing apparatus according to the first invention decodes coded data recorded on a recording medium in a frame unit having a predetermined time length. In the fast-forward reproduction processing, the encoded data recorded on the recording medium is read at predetermined frame intervals, and the read frame-encoded data and the frame-encoded data follow. A control means is provided for performing a time-base compression process using a plurality of frame-encoded data and controlling the reproduction.

The fast-forward reproducing apparatus according to the second invention is the fast-forward reproducing apparatus according to the first invention, wherein the control means performs time-axis compression on all the read frames when the reproduction speed is less than a predetermined value. When the reproduction speed is higher than a predetermined value, the frame-coded data read and a predetermined number of frame-coded data following the frame-coded data are subjected to the time-axis compression process and reproduced. At the same time, control is performed so that a predetermined number of subsequent frames are not reproduced.

A fast-forward reproducing apparatus according to a third aspect of the present invention is the fast-forward reproducing apparatus according to the second aspect, wherein the predetermined value is four times the normal reproduction speed. That is, the fast-forward reproduction device according to the first aspect of the present invention decodes the encoded data recorded in the recording medium in units of frames having a predetermined time length and performs fast-forward reproduction, and then encodes the encoded data recorded in the recording medium. Is read out every predetermined frame interval,
The read frame encoded data and a plurality of frame encoded data subsequent to the frame encoded data are used to perform a time-axis compression process and reproduce the frame.

A fast-forward reproducing apparatus according to a second aspect of the present invention is the fast-forward reproducing apparatus according to the first aspect of the present invention, wherein when the reproduction speed is equal to or lower than a predetermined value, all the read frames are time-axis compressed and reproduced. However, when the reproduction speed is higher than a predetermined value, the frame encoded data read,
The time-axis compression processing is performed on the frame-encoded data following the frame-encoded data and the frame-encoded data is reproduced, and the subsequent frame is controlled not to be reproduced.

Further, the fast-forward reproducing apparatus according to the third aspect of the present invention is such that, in the fast-forward reproducing apparatus of the second aspect, a reproduction speed that is four times the normal reproduction speed is used as the predetermined value.

[0011]

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 digital voice recording / reproducing apparatus to which the fast-forward reproducing apparatus of the present invention is applied. In FIG. 1, a microphone 1 includes a digital signal processing unit (hereinafter referred to as DSP) 5 via an amplifier (AMP) 2, a low pass filter (LPF) 3 and an analog / digital (A / D) converter 4. It is connected to the A1 terminal. In addition, the speaker 13 is an amplifier (AMP)
It is connected to the A2 terminal of the DSP 5 via 12 and a digital / analog (D / A) converter 11.

The A3 terminal of the DSP 5 is connected to the data input / output (I / O) buffer 7 via the control circuit 6.
The A4 terminal is directly connected to the data input / output (I / O) buffer 7. The data input / output (I / O) buffer 7 is connected to the T1 terminal of the main control circuit 8 as a control means. The main power switch (S
The battery BAT is connected via W1) 16, the memory control circuit 9 is connected to the T3 terminal, the semiconductor memory 10 as a removable recording medium to the device is connected to the T4 terminal, and the T5 terminal is driven. A display 15 is connected via the circuit 14.

Further, the main control circuit 8 has a recording button REC as an operation button, a play button PL, a stop button ST, a fast forward button FF, a fast rewind button REW, an I (instruction) mark button I, an E (end) mark. Button E and the like are connected.

The main control circuit 8 controls the operation of the DSP 5, the memory control circuit 9 and the semiconductor memory 10 in response to the operation of the above-mentioned operation buttons and switches. The main control circuit 8 controls the drive circuit 14 to control the display 1.
5 displays various information such as an operation mode.

Further, the inside of the semiconductor memory 10 is composed of a temporary recording medium section and a main recording medium section. As the main recording medium, for example, a flash memory, a magneto-optical disk, a magnetic disk, a magnetic tape, or the like is used. Further, as the temporary recording medium, for example, one that can read and write at a relatively high speed as compared with the main recording medium such as SRAM, EEPROM, high dielectric memory or flash memory is used.
In this embodiment, of these, a flash memory is used as the main recording medium and an SRAM is used as the temporary recording medium. The address, which is the information indicating the recording position of the audio information, may be recorded in the detachable semiconductor memory 10, and a semiconductor memory (not shown) attached to the memory control circuit 9 provided on the recording / reproducing apparatus side ( It may be recorded in an internal recording section).

FIG. 2 is a diagram showing a recording configuration of the semiconductor memory 10 described above. That is, the memory space is roughly divided into the index section 10A and the audio data section 10B. The index section 10A includes a plurality of voice message files 10B1,1 recorded in the voice data section 10B.
0B2, 10B3, ... Operation start position information 10A1, operation end position information 10A2, recorded date and time, information 10A3 relating to other code modes and operation conditions, and the current operation in the audio data section 10B. Operating position information 10A4 indicating the position is recorded.

The above-mentioned I mark and E mark are as follows. The I mark is a mark that is recorded by the person who recorded the text at the time of recording by operating the I mark button I in order to indicate the priority relationship between the plurality of texts recorded in the semiconductor memory 10. As a result, when performing typing or the like while playing back a text in which a typist or secretary is recorded, it is possible to perform typing according to the priority relationship designated by the text recorder. Further, the E mark is used to indicate a break between a plurality of documents, and the person who recorded the text can record the E mark by operating the E mark button E to notify the typist of the break of the document.

In the above configuration, when recording audio,
An analog signal obtained from the microphone 1 is amplified by an amplifier (AMP) 2 and a low-pass filter (LP
F) After passing through 3, the signal is converted into a digital signal by an analog / digital (A / D) converter 4 and input to the DSP 5. The DSP 5 compresses this digital signal under the control of the control circuit 6 and sends it as audio data to the main control circuit 8 via the data input / output (I / O) buffer 7. The main control circuit 8 gives an appropriate address signal to the memory control circuit 9 and records the audio data supplied from the data I / O buffer 7 in the semiconductor memory 10.

During audio reproduction, the main control section 8 reads out audio data recorded in the semiconductor memory 10 and supplies it to the DSP 5 via the data I / O buffer 7. DSP
The audio data is decompressed in 5, converted into an analog signal by a digital / analog (D / A) converter 11, amplified by an amplifier (AMP) 12, and then the speaker 1
3 is output.

Next, details of the fast-forward reproduction processing of the above-mentioned digital audio recording / reproducing apparatus will be described with reference to the flowchart of FIG. First, when the fast-forward button FF or the fast-reverse button REW shown in FIG. 1 is pressed during the reproducing operation, the mode is changed to the fast-forward reproducing mode. In order to simplify the description, the fast-forward reproduction speed is fixed at 20 times the speed during reproduction. First, the DSP 5 carries out a four-fold time base compression process from the position indicated by the current encoded data read pointer (step S1). The details of the quadruple time base compression processing will be described later, but here, from the first frame to the fourth frame.
TDHC (Time Domain Harmonic Compr.
The description will be made assuming that compressed audio data of one frame length is generated by performing time compression processing by the ession) method.

The compressed data of one frame length obtained by this compression is converted into an analog signal by the D / A converter 11 shown in FIG. 1, amplified by the amplifier (AMP) 12, and then output by the speaker 13. While the voice is being output, the CPU 8 detects whether or not any one of the fast-forward button FF and the fast-reverse button REW is pressed (step S2), and if the fast-forward button FF is pressed. For example, it is recognized as fast-forwarding, and the position indicated by the encoded data read pointer is advanced by 16 frames to obtain new operation start position information 10A1 (FIG. 2) (step S3). This means that the frame has advanced by 20 frames from the first reproduction position. That is,
Operation start position information 10A1 is obtained by performing quadruple time compression.
The position indicated by the coded data read pointer as is at the head of the coded data of the fifth frame, and by advancing by 16 frames further than this, it advances by 20 frames.

On the other hand, when it is detected in step S2 that the fast-reverse button REW is pressed, it is recognized as the fast-reverse processing, and the position indicated by the current encoded data read pointer is returned by 24 frames ( Step S
4).

Next, it is detected whether the fast-forward button FF or the fast-return button REW is released (step S
5) If the separation is detected, it is recognized that the fast-forward reproduction has ended, and the process is exited. Otherwise, jumping to step S1 and repeating the above-mentioned processing, the 20-fold speed fast-forward reproduction processing is performed.

In the above description, the fast-forward reproduction process fixed at 20 × speed is limited, but for example, the fast-forward process is started and initially starts at 2 × speed, 4 ×, 6 ×, 8 ×.
The magnification is increased every 2 seconds such as double, 10 times, and final is 20 times. At this time, the time axis compression processing for the double speed fast-forward playback processing is doubled, and the four-speed fast forward playback processing is performed. For the above, the time axis compression processing of 4 times is performed, and the time axis compression processing of 4 times is also performed for the subsequent magnifications. Here, in all of the fast-forward reproduction processing of 4 times or more, the time axis compression processing of 4 times is performed because the processing speed becomes slower or the reproduction is performed when more frames are compressed than the time axis compression of 4 times. This is because the content of the content cannot be understood. For the above reason, in the present embodiment, the time axis compression is performed from 2 times to a maximum of 4 times as the reproduction level within the range in which the processing speed and the contents can be understood.

Next, details of the quadruple time base compression processing in step S1 of the flow chart shown in FIG. 3 will be described with reference to FIGS. 4 and 5. In this time compression processing, the time axis compression is performed by the TDHC method as described above, and the time axis compression is performed on the audio data of one frame length using the encoded data of four frames. First, the encoded data for one frame (here, the encoded data of the first frame shown in FIG. 5A) is read from the position indicated by the current encoded data read pointer, and the decoding process is performed (step S10). . Next, a waveform obtained by performing windowing processing on the speech waveform of the decoded coded data using a window that decreases at a constant reduction rate as shown in FIG. Yes (step S11). Next, the encoded data of the second frame shown in FIG. 5 (A) is read out and a decoding process is performed (step S12). Then, the decoded speech waveform is obtained by performing a windowing process using a window having a characteristic opposite to that of step S11 as shown in FIG. 5B, that is, a window increasing at a constant increase rate. The waveform is set to (b) (step S13). Next, the waveform obtained by adding the above waveforms (a) and (b) is defined as (c) (step S1).
4). At this point, the waveform (c) is a waveform whose time axis is doubled.

Next, the encoded data of the third frame shown in FIG. 5 (A) is read out and a decoding process is performed (step S).
15). Next, the waveform obtained by multiplying the voice waveform of the decoded coded data by the window having the same characteristics as in step S11 is defined as (d) (step S16). Next, the encoded data of the fourth frame shown in FIG. 5 (A) is read out and a decoding process is performed (step S17). Then, a waveform obtained by multiplying the decoded voice waveform by the window having the same characteristics as in step S13 is set as (e) (step S18). Next, the waveform obtained by adding the waveforms (d) and (e) is defined as (f) (step S19). At this time, the waveform (f) is twice the time-axis compressed data obtained by adding the third frame and the fourth frame.

Here, the waveform obtained by performing windowing processing using a window that decreases at a constant reduction rate on the audio data (c) that has been further time-compressed by a factor of 2 is taken as (g) (step S20). ), And the waveform obtained by performing the windowing process using the window that increases at a constant increase rate on the waveform (f) is defined as (h) (step S21). Next, the waveforms (g) and (h) are added to obtain the audio data (i) which is time-axis compressed four times (step S22). The audio signal (i) of one frame length which is time-axis compressed four times as much as D
The signal is output from the speaker 13 via the / A converter 11 and the amplifier (AMP) 12 (step S23), and the process exits.

In the above-described embodiment, when the fast-forward reproduction speed is equal to or lower than the predetermined value (four times speed in this case), the read frame is not skipped and the encoded data of the first frame,
Main control as a control means for performing time-axis compression processing and reproduction using all encoded data of a plurality of frames (here, second, third, and fourth frames) following this first frame It is controlled by the circuit 8. Therefore, in the fast-forward reproduction process of about 2 to 4 times, the time-axis-compressed sound is reproduced, so that a good reproduction result can be obtained, and the user can understand the reproduced content. .

When the fast-forward reproduction speed is higher than a predetermined value (four times speed in this case), the read frame encoded data of the first frame and a predetermined number of frames (second and second frames) following the frame encoded data. (3rd and 4th frames), the encoded data is time-axis compressed and reproduced, and a predetermined number of frames thereafter (16 frames from the 5th to 20th frames) are skipped without being reproduced. Are controlled. Therefore, for example, in the case of fast-forward reproduction at a high speed of 10 times or 20 times, by performing time-axis compression, it is possible to distinguish between voiced and silent even if the reproduced content cannot be understood. It can be stopped. In this way, the operator can obtain a desired reproduction result according to the set fast-forward reproduction speed, regardless of whether the fast-forward reproduction speed is equal to or lower than the predetermined value or equal to or higher than the predetermined value.

[0030]

According to the invention described in claim 1, there is an effect that a good reproduction result can be obtained even when performing fast-forward reproduction. According to the inventions described in claims 2 and 3, in addition to the effect of the invention described in claim 1, there is an effect that a reproduction result desired by the user can be obtained according to the set fast-forward reproduction speed. .

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a digital audio recording / reproducing apparatus to which a fast-forward reproducing apparatus of the present invention is applied.

FIG. 2 is a diagram showing a recording configuration of the semiconductor memory shown in FIG.

FIG. 3 is a flowchart for explaining details of fast-forward reproduction processing according to the present embodiment.

FIG. 4 is a flowchart showing details of a quadruple time base compression process in the flowchart shown in FIG.

FIG. 5 is a diagram for explaining details of a fourfold time base compression process in the flowchart shown in FIG.

[Explanation of symbols]

1 ... Microphone, 2 ... Amplifier (AMP), 3 ... Low pass filter (LPF), 4 ... A / D converter, 5 ... Digital signal processing part (DSP), 6 ... Control circuit, 7 ... Data I / O Buffer, 8 ... Main control circuit (CPU), 9 ... Memory control circuit, 10 ... Recording medium (semiconductor memory), 11 ...
D / A converter, 12 ... Amplifier (AMP), 13 ... Speaker, 14 ... Driving circuit, 15 ... Indicator.

Claims (3)

[Claims] 1. A method for decoding coded data recorded on a recording medium in a unit of frame having a predetermined time length to perform fast-forward reproduction, wherein at the time of fast-forward reproduction processing, the encoding recorded on the recording medium is performed. Control for reading data at predetermined frame intervals and performing control so that time-axis compression processing is performed using the read frame-encoded data and a plurality of frame-encoded data that follows this frame-encoded data for reproduction. A fast-forward reproduction device comprising means. 2. When the reproduction speed is less than or equal to a predetermined value, the control means performs time-axis compression processing on all the read frames to reproduce, and when the reproduction speed is greater than the predetermined value, the read frame encoded data and The frame-coded data following the frame-coded data is subjected to the time-base compression processing and played back, and a control is performed so that a predetermined number of frames thereafter are not played back. The fast-forward playback device described in 1. 3. The fast-forward reproduction device according to claim 2, wherein the predetermined value is four times the normal reproduction speed.