JPH04324778A - Recorder - Google Patents

Abstract

PURPOSE:To arrange the quality of a reproduction signal of a picture and an audio signal recorded on a memory card to a same degree. CONSTITUTION:The user commands one of compression modes #1, #2, #3 by using a compression mode changeover switch 84 to a system control circuit 50. The system control circuit 50 selects a data compression circuit 28 with respect to a picture and selects a data compression circuit 68 with respect to an audio signal when the mode designated by a compression mode changeover switch 84 is the mode #1, and selects a data compression circuit 30 with respect to a picture and selects a data compression circuit 70 with respect to an audio signal when the mode designated by a compression mode changeover switch 84 is the mode #2, and selects a data compression circuit 32 with respect to a picture and selects a data compression circuit 72 with respect to an audio signal when the mode designated by a compression mode changeover switch 84 is the mode #3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording device for recording still images, audio, and data in a solid-state memory device such as a semiconductor memory.

0002

[Prior Art] In recent years, DRAM and SRA have been used as recording media.
Electronic still cameras have been proposed that use memory cards with solid state memory elements such as M, EEPROM. These electronic still cameras use a method that manages the storage area of a memory card by dividing it into multiple blocks (hereinafter referred to as clusters) of a predetermined storage capacity, and can store not only images but also audio and data. It is specified that it can be recorded.

0003

[Problem to be Solved by the Invention] However, when recording images and audio in association with each other, for example, the user can select compression methods (modes) for images and audio separately.
Due to the difference in compression rates between images and audio, users may feel uncomfortable during playback.

[0004] An object of the present invention is to provide a recording device that eliminates such inconveniences.

[0005]

[Means for Solving the Problems] A recording device according to the present invention is a recording device for recording still images and audio on a recording medium, and includes an image compression means for compressing image information to be recorded, and an audio recording device to be recorded. An audio compression means for compressing information, a compression mode designation means for designating a compression mode of the information, and a compression operation for the image compression means and the audio compression means in a predetermined correspondence relationship according to the specification by the compression mode designation means. The invention is characterized by comprising a control means for setting.

[0006]

[Operation] With the above means, the degree of compression of images and sounds recorded on a recording medium is always maintained in a predetermined correspondence relationship. Therefore, at the time of reproduction, it is possible to enjoy reproduced images and reproduced sounds that do not give a sense of discomfort as a reproduced signal quality.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to an electronic still camera having a playback function will be described below with reference to the drawings. FIG. 1 shows a block diagram of a recording system according to an embodiment of the present invention, and FIG. 2 shows a block diagram of a reproduction system. Components common to the recording system and the reproduction system are given the same reference numerals.

In FIGS. 1 and 2, A is the camera body;
B is a memory card that can be attached to and detached from the camera body A. The storage area of memory card B is divided into a card management area and a data area, and the data area is divided into units called clusters. Information such as images, audio, and data to be recorded is handled in units called packets. Card management area includes header, packet identification,
Directory and memory allocation table (
MAT). The header contains the format number, card number, number of remaining clusters, number of used clusters, last used packet number, first unused cluster number, and card number.
Labels etc. are recorded. The packet identification consists of the type and attribute of each recorded packet and related information between the packets. The directory consists of the number of the starting cluster of each packet. The memory allocation table records, for each cluster, the number of the cluster connected to that cluster.

[0009] The data area is logically handled in units called packets. A packet consists of a packet header and packet data of arbitrary length. The packet header consists of packet information, date and title. The packet information records image and audio encoding methods, compression modes, and recording modes. In the case of an image, the number of horizontal and vertical pixels and the aspect ratio of the pixels are also recorded. Packets are physically distributed and recorded in multiple clusters.

First, the basic operation of the recording system shown in FIG. 1 will be briefly explained. The procedure for storing image information in memory card B is as follows. That is, an object image captured by the photographic lens 10 is made incident on the photoelectric conversion surface of the image sensor 14 for a predetermined period of time by the shutter 12, and the image sensor 14 converts the optical image into an electrical signal. An image signal from the image sensor 14 is outputted by a timing pulse from a timing pulse generation circuit 16, is converted and separated into a luminance signal and a color signal by a video signal processing circuit 18, and is supplied to an A/D converter 20. The A/D converter 20 includes a timing pulse generation circuit 16
Timing pulses from digitize the analog input and apply it to image memory 22. The address counter 22 increments the address it holds in response to the timing pulse from the timing pulse generation circuit 16, and the output data of the A/D converter 20 is written to the address indicated by the address counter 24. .

When one screen worth of image data is written to the image memory 22, the stored data in the image memory 22 is read out from the address by the address counter 26, and the data compression circuits 26, 26 each have a different compression method or compression rate. 2
The signal is applied to the data compression circuit (for example, the circuit 26) selected by the switch 32 among the data compression circuits 8 and 30. As a compression method, for example, adaptive differential PCM (ADPCM)
and adaptive discrete cosine transform (ADCT). The data compressed by the data compression circuit (eg, circuit 26) is written back to image memory 22.

Compression by the compression circuits 26, 28, 30 is as follows:
Different compression formats may be used, or the same compression format may have different compression ratios.

When the compression process for one screen worth of image data is completed, the error correction code generation circuit 36 generates an error correction code (CRC, Reed-Solomon code, etc.) for each predetermined number of compressed data. This error correction code is written to a predetermined address along with the compressed data stored in the image memory 22. The image data (compressed data) to which the error correction code has been added is read from the address specified by the address counter 38 and supplied to the external memory card B via the memory card interface 40. .

Memory card B has interface 4
4, a memory control circuit 46 and a memory circuit 48. Prior to storing image data, the system control circuit 50:
Management data (starting cluster number, attributes of stored data, data compression method, correspondence with other stored data, etc.) is supplied to the memory card B via the interface 40, and the memory control circuit 46 receives this management data. Based on
The first cluster number for starting storage is set in the cluster address pointer, and the memory address pointer indicating the memory address within the cluster is reset. Then, the data supplied via the interface 44 is sent to the memory address of the memory circuit 48.
Stores at the address indicated by the pointer and stores it at the memory address.
Increments the pointer to prepare for storing the next data. This operation is repeated for each predetermined amount of image data until one sheet of image data is stored in the memory circuit 48.

Note that the system control circuit 50 stores image data (the same applies to the following audio data) in the memory circuit 4.
When it is confirmed that the image data has been stored in one cluster of 8 (actually, this is recognized by counting the number of transferred data using a counter), the transfer of image data to memory card B is temporarily interrupted. When memory card B is connected to camera body A, the memory management data of memory card B is read out and stored in a memory (not shown) as search data, and the system control circuit 50 uses the search data to perform the following operations. The number (address) of an unused cluster that can store image data is checked, and the obtained cluster number is transferred to the memory control circuit 46 of memory card B. The memory control circuit 46 sets the transferred cluster number in the cluster address pointer and resets the memory address pointer. The system control circuit 50 is
After the cluster number is transferred to the memory control circuit 46, a counter that counts the number of image data transfers is reset, and image data transfer is restarted.

After one piece of image data is stored in memory card B as described above, system control circuit 50 transfers the management data to memory card B. This management data is sent to the memory circuit 48 by the memory control circuit 46.
is stored in a predetermined area. This registers that the image has been recorded.

The processing procedure for recording audio information on memory card B is as follows. That is, the audio signal output from the microphone 52 is amplified by the amplifier 54 and noise reduced by the noise reduction circuit 56. A/D converter 5
8 digitizes the output of the noise reduction circuit 56 using the timing pulse from the timing pulse generation circuit 60 and applies it to the audio memory 62 . The address counter 64 increments the address it holds in response to the timing pulse from the timing pulse generation circuit 60, and the output data of the A/D converter 58 is written to the address indicated by the address counter 64. .

The system control circuit 50 monitors the count value of the address counter 64 and selects one of the data compression circuits 68, 70, 72 with the switch 66 at predetermined intervals (or every predetermined number of data). , performs data compression. The data compression circuits 68, 70, and 72 compress audio data using different compression methods or compression rates. Examples of compression methods include adaptive differential PCM (ADPCM) and adaptive delta transformation (ADM). Data compression circuit (
For example, the data compressed by the circuit 68) is written back into the audio memory 62. Note that the address counter 74 defines the address for reading data from the audio memory 62 and writing compressed data to the audio memory 62 for data compression.

The compression by these data compression circuits 68, 70, and 72 is performed using the same compression format but with different compression rates.
Different compression formats are also possible.

An error correction code generation circuit 76 generates an error correction code (CRC, Reed-Solomon code, etc.) for compressed audio data in units of a predetermined number of compressed data. This error correction code is written to a predetermined address along with the compressed data stored in the audio memory 62. Address counter 74 is also used at this time.

When the audio data that can be stored in one cluster of the memory card B is stored in the audio memory 62, the system control circuit 50 controls the storage of recordable (unused) data from the above-mentioned search data of the memory card B. ) search for clusters,
The obtained cluster number is transferred to the memory control circuit 46 of memory card B via interfaces 40 and 44. The memory control circuit 46 sets the transferred cluster number in the cluster address pointer and also sets the memory address pointer indicating the memory address within the cluster.
Reset pointer. The system control circuit 50 waits for a predetermined time after transferring the cluster number (or after waiting for a predetermined time (or
(according to a data transfer request from card B), the address counter 78 reads the audio data (compressed data) and its error correction code from the audio memory 62, and
Transfer to card B.

In memory card B, the transferred data is stored in the memory circuit 48 at the address indicated by the memory address pointer, and the memory address pointer is incremented to prepare for storing the next data. This operation is repeated until data for one cluster is stored in the memory circuit 48.

When the system control circuit 50 confirms by the address counter 78 that one cluster's worth of audio compressed data has been transferred to the memory card B, it transfers the management data to the memory card B. This management data is stored at a predetermined location in the memory circuit 48. This registers that audio has been recorded in the cluster.

In this embodiment, the image data compression circuit 34
and audio data compression circuit 68, and image data compression circuit 3.
The data compression circuit 6 and audio data compression circuit 70, the image data compression circuit 38, and the audio data compression circuit 72 have compression methods and/or compression ratios that make the reproduced signal quality comparable to each other. The details will be described later, but when recording images and audio in association with each other (for example, when importing them substantially at the same time or when dubbing images or audio), when compressing the images with the data compression circuit 34, the audio is converted into data. compression circuit 68
When the image is compressed by the data compression circuit 36, the audio is compressed by the data compression circuit 70, and when the image is compressed by the data compression circuit 38, the audio is compressed by the data compression circuit 72.

The basic operation of the reproduction system shown in FIG. 2 will be explained. The image playback operation is as follows. The user uses the operation switch 80 to specify image reproduction and the image to be reproduced. For example, when the image playback mode is selected using the operation switch 80, the display device 82 displays the number of the first cluster in which an image is recorded from the above-mentioned search data, and the user selects the image to be played using the operation switch 80. Specified by. The system control circuit 50 transfers the first cluster number of the image to be reproduced to the memory control circuit 46 via the interfaces 40 and 44. Memory control circuit 4
6 is the cluster address of the transferred cluster number.
At the same time, the memory address pointer indicating the memory address within the cluster is reset, and while the memory address pointer is incremented, the data stored in the specified cluster is sequentially read out, and the data stored in the specified cluster is read out sequentially through the interface 44. and sends it to camera body A.

The system control circuit 50 mutes the video output of the video signal processing circuit 98 and resets the address counter 38 to point to the first address of the image memory 22. address counter 38
is thereafter incremented in synchronization with data transfer from memory card B, and data from memory card B is sequentially written to image memory 22 via interface 40. When one cluster of compressed image data (including an error correction code) is stored in the image memory 22, the system control circuit 50 checks from the above-mentioned search data whether there is a cluster in which subsequent data is stored, If there is, reading from the corresponding cluster and storing into the image memory 22 continues.

When the compressed image data for one image and its error correction code are stored in the image memory 22, the error detection and correction circuit 86 performs error detection and correction using the error correction code.
The error-corrected compressed image data is written into the image memory 22. Needless to say, when writing into the image memory 22, the added error correction code is removed. The address counter 26 defines the address for reading data from and writing data to the image memory 22 during error detection.

After the error correction is completed, the system control circuit 50 checks the compression method of the image from the management data, and uses the switch 88 to select the data expansion circuit corresponding to the compression method from among the data expansion circuits 90, 92, and 94. If there is no corresponding data decompression circuit, the display device 82 will alert the user. A data decompression circuit 90 reads compressed image data from the image memory 22 under address control by the address counter 26 and selects it by a switch 88.
, 92 and 94, and write the data into the image memory 22.

At the end of the data decompression process, the system control circuit 50 releases the video signal processing circuit 98 from the mute state, and uses the address counter 24 to register the image memory 22.
Read image data from. Address counter 24 increments the address it holds in response to timing pulses from timing pulse generation circuit 16. The D/A converter 96 is a timing pulse generating circuit 1
In response to timing pulses from 6, the image memory 22
The image data is converted into an analog signal and applied to the video signal processing circuit 98. The video signal processing circuit 98 has a D/
A synchronizing signal is added to the analog image signal from the A converter 96 and outputted to the video output terminal 100 as a standard format video signal.

[0030] The audio reproduction operation will be explained. Audio reproduction is performed when specified using the operation switch 80 in the same manner as in the case of image reproduction, or when audio is recorded in association with the image to be reproduced. The system control circuit 50 checks the first cluster number in which the sound specified by the operation switch 80 or the sound to be played simultaneously with the playback image is recorded from the above-mentioned search data, and sends it to the memory control circuit via the interfaces 40 and 44. Transfer to 46. The memory control circuit 46 stores 1 in the same way as in the case of images.
The data for the cluster is read from the memory circuit 48 and sent to the camera body A via the interface 44. The system control circuit 50 puts the audio signal processing circuit 114 into an output mute state, as in the case of image reproduction.

The audio compressed data and its error correction code from memory card B are applied to audio memory 62 via interface 40 and stored in audio memory 62 in sequence by address counter 78 . The error detection and correction circuit 102 performs error detection and correction using an error correction code, and writes the error-corrected audio compressed data into the audio memory 62. Needless to say, when writing into the audio memory 62, the added error correction code is removed. The address counter 74 defines the address for reading data from the audio memory 62 and writing data to the image memory 62 during error detection.

After the error correction is completed, the system control circuit 50 checks the audio compression method from the management data, and switches the data decompression circuits 106, 108, 110 by the switch 104.
Select a data decompression circuit corresponding to the compression method from . If there is no corresponding data decompression circuit, the display device 82
to warn the user. Under address control by address counter 74, compressed audio data is read from audio memory 62, expanded by data expansion circuits 106, 108, and 110 selected by switch 104, and written into audio memory 62. This restores the original audio data.

After the data decompression process is completed, the audio memory 62
The audio data is read out sequentially under the control of the address counter 64. Address counter 64 increments the address it holds in response to timing pulses from timing pulse generation circuit 60. The D/A converter 112 converts the audio data from the audio memory 62 into an analog signal in response to the timing pulse from the timing pulse generating circuit 60, and converts the audio data from the audio memory 62 into an analog signal.
14. The system control circuit 50 releases the audio signal processing circuit 114 from the mute state, and the audio signal processing circuit 114 smoothes the analog audio signal from the D/A converter 112, adjusts the level if necessary, and outputs it to the audio output terminal 116. Output.

The system control circuit 50 sequentially reads recorded data from the cluster in which the audio following the audio being reproduced is recorded, transfers it to the audio memory 62, and processes it in the same manner as described above. This is repeated until the continuous audio ends (that is, until all clusters in which the series of audio are recorded are played back).

The operation of the system control circuit 50 during recording will be explained in detail. FIGS. 3, 4 and 5 collectively show a flowchart of the operation.

When the power is turned on, the system control circuit 50 initializes flags, control variables, etc. (S1), and confirms that memory card B is set (S2). Management data is read from the set memory card B (S3), and if all clusters are unused, the recording mode is entered as a matter of course, and if there are no unused clusters, the playback mode is entered (S4, 5). If there is an unused cluster, the mode is set to playback mode or recording mode depending on the operation mode flag (S6).

[0037] When the operation mode flag is recording mode,
First, it is checked whether the circuit system is in the recording mode operating state (S7), and if it is not, it is put into the recording mode (S8). For example, the video output and audio output are muted (S8).

When a change in the state of the compression mode changeover switch 84 is detected, the specified compression mode #1, #2, #3 is selected.
Switch the switches 34, 66 according to the data compression circuits 28, 68; 30, 70; 32, 72 (
S10, 11, 12, 13, 14, 15, 16).

Thereafter, an image recording request or an audio recording request from the operation switch 80 is awaited. In response to the image recording request (S17), it is checked whether the number of unused clusters is sufficient to record the image in the set image compression mode (S18).
), and if there are enough images, store the image taken by the image sensor 14 in the image memory 22 (S19), compress it in the selected compression mode (S20), and record it on the memory card B (
S21). If it is insufficient, a warning to that effect is displayed on the display device 82 (S22).

In response to the audio recording request (S23), it is checked whether there are any unused clusters (S24). If there is no unused cluster, a warning is given on the display device 82 and the voice input operation is stopped (S32, 33). If there is an unused cluster, the system control circuit 50 activates the audio input system and starts capturing audio input from the microphone 52 into the audio memory 62 (S25).

When a stop request is input through the operation switch 80 (S27) or when one cluster worth of audio data is taken into the audio memory 62 (S28), the audio data in the audio memory 62 is compressed in the selected compression mode. The audio data is compressed (S29), and the compressed audio data is recorded in memory card B together with its error correction code (S30). If there is a stop request (S31), the voice input operation is stopped,
If there is no stop request (S31), voice input and recording to memory card B continue as long as there are unused clusters (S26), and when there are no unused clusters (S26).
), the display device 82 gives a warning and stops the voice input operation (S32, 33).

In the above embodiment, a memory card is used as the information recording medium, but it goes without saying that the present invention can also be applied to a recording device using a disk-shaped recording medium or a tape-shaped recording medium.

[0043]

Effects of the Invention As can be easily understood from the above explanation, according to the present invention, in response to the user's compression mode specification,
Since the image compression mode and the audio compression mode are set together, the compression rate including the compression method can be maintained in a predetermined correspondence relationship. Therefore, the reproduction signal quality has a constant relationship, and the discomfort during reproduction can be alleviated or alleviated.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a recording system according to an embodiment of the present invention.

FIG. 2 is a configuration block diagram of remolding.

FIG. 3 is a part of a flowchart of the system control circuit 50 during recording.

FIG. 4 is a part of a flowchart of the system control circuit 50 during recording.

FIG. 5 is a part of a flowchart of the system control circuit 50 during recording.

[Explanation of symbols]

Claims (1)

[Claims] Claim 1: A recording device for recording still images and audio on a recording medium, comprising an image compression means for compressing image information to be recorded, an audio compression means for compressing audio information to be recorded, and an information compression means. It is characterized by comprising a compression mode specifying means for specifying a mode, and a control means for setting the image compression means and the audio compression means to compression operations having a predetermined correspondence relationship in accordance with the specification by the compression mode specifying means. recording device.