JP4983211B2 - Audio playback device - Google Patents

Description

  The present invention relates to an audio playback device, and more particularly to playback of a rhythm sound source.

  In general, in a sound source device, PCM audio data for a sound source is compressed by a method such as MP3, AAC, TwinVQ, ATRAC, ADPCM and stored in a ROM. However, in a multitrack recorder with a built-in rhythm sound source, PCM data for the rhythm sound source is often stored in the ROM by a compression method such as DPCM (Differential Pulse Code Modulation). The reason is that decoding is easy. In order to use a method such as MP3 that can maintain high sound quality despite a high compression rate, a dedicated decoder is required, and a processor with high processing capability is required when processing by a CPU or DSP and software. Therefore, the cost increases. While DPCM does not require a processor with high processing capability, it has a low compression rate, so a large-capacity ROM is required when storing many rhythm sound sources.

  Patent Document 1 below discloses storing PCM audio data in a ROM.

  Patent Document 2 below discloses a digital audio device that reproduces audio data stored on a CD, synthesizes it with external audio data input from an input terminal, and outputs it. 2 and 3 are configuration diagrams of the digital audio playback device disclosed in Patent Document 2. FIG. The digital audio playback apparatus includes a CD playback unit 21, a digital data processing circuit 22, an operation unit 23, a display unit 24, an input amplifier 25, an analog-digital converter (ADC) 26, a digital-analog converter (DAC) 27, and an analog signal synthesis unit 28. A mute switch 29 and an output amplifier 30.

  The CD playback unit 21 includes a spindle motor 31, a pickup 32, and a CD playback processing unit 33, plays back the music CD 11 and supplies it to the digital data processing circuit 22. On the other hand, an electronic musical instrument such as an electric guitar is connected to the input terminal Tin1, and an analog audio signal is input from the electronic musical instrument. The analog audio signal adjusted by the input amplifier 25 is converted into digital data by the ADC 26 and supplied to the digital data processing circuit 22.

  The digital data processing circuit 22 receives various operation signals from the operation unit 23, performs various processes on the reproduction data supplied from the CD reproduction unit 21, and processes the digital data of the electronic musical instrument supplied from the input terminal Tin 1. Apply effects and combine with playback data and output. An output from the digital data processing circuit 22 is converted into an analog audio signal by the DAC 27, and is appropriately combined with another analog audio signal input from the input terminal Tin2 by the combining unit 28 and supplied to the mute switch 29. The mute switch 29 is supplied with a mute instruction from the operation unit 23. The audio signal from the mute switch 29 is output to the outside through the output amplifier 30. The display unit 24 displays the number of music CDs 11 being played by the CD playback unit 21, the playback time, the remaining time, the operation mode, and the like.

  As shown in FIG. 3, the digital data processing circuit 22 includes an interface 51, a memory 52, a de-emphasis processing unit 53, a key / pitch / tempo control unit 54, a balance control unit 55, a buffer memory 56, an input processing unit 57, a buffer A memory 58, an effect processing unit 59, an output switching unit 60, a tuning control unit 61, a level control unit 62, a digital data synthesis unit 63, and a buffer memory 64 are included. The memory 52 stores a predetermined amount of reproduction data reproduced by the CD reproduction unit 21 via the interface 51. The data read from the memory 52 is subjected to de-emphasis processing (reduction of high frequency response) by the de-emphasis processing unit 53, and the key / pitch / tempo control unit 54 performs key / pitch according to the operation signal from the operation unit 23. Pitch / tempo control. The reproduction level of the key / pitch / tempo controlled reproduction data is adjusted by the balance control unit 55 and stored in the buffer memory 56.

  On the other hand, digital data from the electronic musical instrument is stored in the buffer memory 58 via the input processing unit 57 and supplied to the effect processing unit 59. The effect processing unit 59 executes various effect processes in accordance with operation signals from the operation unit 23. For example, processing set in an effector such as an electric guitar is possible, such as distortion, compressor, tone control, flanger, reverb, delay, phaser, exciter, and the like. The digital data subjected to the effect processing is level-adjusted by the level control unit 62 and then supplied to the digital data synthesis unit 63 via the output switch 60. The digital data synthesizing unit 63 synthesizes the reproduction data accumulated in the buffer memory 56 and the digital data subjected to the effect processing, accumulates them in the buffer memory 64, and outputs them to the outside.

JP 2002-169564 A JP 2004-220708 A

  In the digital audio apparatus shown in FIGS. 2 and 3, the rhythm sound source can be stored in the ROM. However, as described above, storing the rhythm sound source as DPCM data that can be easily decoded increases the capacity of the ROM. I will.

  An object of the present invention is to provide an audio apparatus capable of reproducing a rhythm sound source with a simple configuration.

The present invention is encoded by a predetermined method, a reproducing means for reproducing by decoding the recorded audio signal to a first recording medium and a second recording medium for recording a rhythm sound source encoded by the predetermined method a, the playback unit, the a in the audio signal and the rhythm sound source that reproduces the decoding by a common decoding unit, wherein at least a portion of said rhythm tone source when the apparatus is started and decoded by the decoding unit record the second recording medium or the third recording medium, reads the second recording medium or said third decoded rhythm tone source which is recorded in a recording medium, and reproduces in response to the operation signal It is characterized by that.

  According to the present invention, since the audio data and the rhythm sound source are decoded and reproduced by the common reproducing means, the rhythm sound source can be reproduced with a simple configuration. In addition, since the rhythm sound source is decoded in advance when the apparatus is activated, quick reproduction is possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The audio apparatus of the present embodiment has substantially the same configuration as the digital audio apparatus in FIGS. 2 and 3, and the same members as those in the digital audio apparatus shown in FIGS. To do.

  FIG. 1 is a block diagram showing the configuration of an audio apparatus according to this embodiment. The digital audio apparatus shown in FIG. 2 does not have the CD playback unit 21 but has a flash memory 16 that stores audio data encoded and compressed by MP3. The MP3 audio data stored in the flash memory 16 is read by the memory controller 18 and supplied to the digital data processing circuit 22. An apparatus for reproducing audio data encoded in MP3 is known as an MP3 player.

  The digital data processing circuit 22 includes a ROM 10, a RAM 12, and a CPU 14. As shown in FIG. 3, the CPU 14 includes an interface 51, a de-emphasis circuit 53, a key / pitch / tempo control unit 54, an effect processing unit 59, a digital data synthesis unit 63, and the like. In this embodiment, the MP3 decoding unit 70 is further added. And an MP3 encoding unit 72. The MP3 decoding unit 70 and the MP3 encoding unit 72 may be configured by a dedicated hardware circuit or may be configured by software. In the present embodiment, a case where it is configured by software will be described.

  The MP3 audio data read from the flash memory 16 by the memory controller 18 is supplied to the MP3 decoding unit 70 of the CPU 14. The MP3 decoding unit 70 decodes the MP3 audio data and supplies it to the digital data synthesis unit 63. The decoding process in the MP3 decoding unit 70 is executed according to the MP3 decoding program included as a subroutine in the system program stored in advance in the ROM 10. The decoded audio data is further controlled by the key / pitch / tempo control unit 54 in FIG. 3 in accordance with an operation signal from the operation unit 23, and is balance-controlled by the balance control unit 55 and then supplied to the digital data synthesis unit 63. Is done.

  External audio data from an electronic musical instrument such as an electric guitar or a microphone is converted into digital data by the ADC 26 and then supplied to the digital data processing circuit 22. The CPU 14 of the digital data processing circuit 22 performs effect processing in the effect processing unit 59 in accordance with an operation signal from the operation unit 23 and supplies the processed result to the digital data synthesis unit 63. The digital data synthesizing unit 63 synthesizes the decoded audio data and the effect-processed digital data, supplies them to the DAC 27, converts them into analog signals by the DAC 27, and outputs them to the outside. As shown in FIG. 3, it may be output via a mute switch 29. As a result, external audio data is synthesized with the MP3 audio data and output, and the user can play an electric guitar in accordance with, for example, a playback audio signal, and mix and play it. The combined data from the digital data combining unit 63 may be output to the DAC 27 and supplied to the MP3 encoding unit 72. Whether or not the combined data is also supplied to the MP3 encoding unit 72 is determined according to an operation signal from the operation unit 23. The MP3 encoding unit 72 encodes the combined data by the MP3 method and stores the encoded data in the flash memory 16. The encoding process in the MP3 encoding unit 72 is executed according to the MP3 encoding program included as a subroutine in the system program stored in advance in the ROM 10 as in the MP3 decoding unit 70.

  In addition, the audio device of the present embodiment is configured to be able to reproduce a rhythm sound source. However, the rhythm sound source is not stored in the ROM 10 by the DPCM method as in the prior art, but is encoded by the MP3 method having the higher compression ratio and the audio data and stored in the ROM 10. The required capacity of the ROM 10 can be reduced by encoding and compressing the rhythm sound source by the MP3 method. The MP3 rhythm sound source stored in the ROM 10 is read out, supplied to the digital data processing circuit 22, and decoded by the MP3 decoding unit 70 that decodes the MP3 audio data stored in the flash memory 16. By sharing a decoding unit that decodes the rhythm sound source and a decoding unit that decodes the MP3 audio data, the circuit configuration can be simplified and the cost can be reduced. The rhythm sound source decoded by the MP3 decoding unit 70 is converted into an analog signal by the DAC 27 through the digital data synthesis unit 63 in the same manner as the audio data, and is output to the outside. As the rhythm sound source, a known rhythm sound source such as a bass, a drum, or a piano can be used.

  However, since the rhythm sound source is repeatedly reproduced and output from its use, each time the rhythm sound source instructed from the ROM 10 is read in accordance with the operation signal from the operation unit 23, the MP3 decoding unit 70 decodes it. It is not efficient to output.

  Therefore, in the present embodiment, any one of the rhythm sound sources stored in the ROM 10 at a predetermined timing before the user operates the operation unit 23 to instruct reproduction of the rhythm sound source, preferably at the time of starting the audio device, or All are read from the ROM 10, decoded by the MP3 decoding unit 70, and stored in the RAM 12 in advance, and the rhythm sound source instructed by the user in accordance with the operation signal from the operation unit 23 is read from the RAM 12 and supplied to the DAC 27. Output to. When the apparatus is activated, the system program is read from the ROM 10 and expanded on the RAM 12. However, it can be said that the rhythm sound source is also read together with the system program, decoded, and expanded on the RAM 12. Since the rhythm sound source developed on the RAM 12 exists in the RAM 12 in a decoded state unless the apparatus is turned off, the rhythm sound source can be repeatedly and quickly output in accordance with an instruction from the user. Which rhythm sound source is previously decoded and stored in the RAM 12 may be determined, for example, by the CPU 14 detecting a past use frequency and automatically selecting a rhythm sound source having a high use frequency. The number of rhythm sound sources that are decoded and stored in the RAM 12 at startup may be limited to a certain number. If it is automatically selected and decoded at startup and stored in the RAM 12, but it is not output once and the power of the device is turned off again, the rhythm sound source is not decoded at the next startup. Wasteful processing and RAM capacity reduction can be achieved.

  The audio apparatus of this embodiment can function as an MP3 player, an MP3 rhythm sound source, and an MP3 recorder by having such a configuration. These will be described individually below.

<MP3 player>
The user connects the flash memory 16 to the PC via USB, and stores MP3 audio data from the PC in the flash memory 16. When the flash memory 16 is connected to the audio apparatus of the present embodiment and playback is instructed from the operation unit 23, the CPU 14 reads MP3 audio data from the flash memory 16 via the memory controller 18 and decodes it by the MP3 decoding unit 70. The decoded audio data is converted into an analog signal by the DAC 27 and output to the outside. The user operates the operation unit 23 to adjust the key, pitch, and tempo of the reproduction signal. The key / pitch / tempo control unit 54 of the CPU 14 controls and outputs any or all of the keys / pitch / tempo of the decoded audio data according to the operation signal from the operation unit 23.

  When the user plays an electronic musical instrument such as an electric guitar, the analog audio signal is supplied to the ADC 26 via the input terminal Tin1 input amplifier 41. The ADC 26 converts the input external analog signal into digital data and supplies it to the CPU 14. In response to an instruction from the operation unit 23, the CPU 14 executes effect processing at the effect processing unit 59. Both the decoded key / pitch / tempo-adjusted audio data and the effect-processed digital data are supplied to the digital data synthesis unit 63, synthesized by the digital data synthesis unit 63, supplied to the DAC 27, and output to the outside.

<MP3 rhythm sound source>
Various rhythm sound sources are encoded and stored in the ROM 10 in advance by the MP3 method. When the power of the audio device is turned on, the CPU 14 reads a system program stored in the ROM 10. Next, one of the rhythm sound sources stored in the ROM 10 or all the rhythm sound sources as long as the capacity of the RAM 12 permits is read, decoded by the MP3 decoding unit 70 and stored in the RAM 12. When the flash memory 16 is connected, the rhythm sound source encoded and compressed by the MP3 method may be read from the flash memory 16 instead of the ROM 10, and the decoded rhythm sound source may be stored in the flash memory 16 instead of the RAM 12. . That is,
(1) The data read and decoded from the ROM 10 is stored in the RAM 12 (2) The data read and decoded from the ROM 10 is stored in the flash memory 16 (3) The data read and decoded from the flash memory 16 is stored in the RAM 12 ( 4) The data read from the flash memory 16 and decoded may be stored in the flash memory 16. When the past reproduction history is stored in the ROM 10 or the flash memory 16 and the rhythm sound source is read out from the ROM 10 or the flash memory 16, the rhythm sound source that has been reproduced in the past or the number of times of reproduction in the past is a predetermined value. Only the rhythm sound source as described above may be selected and decoded and stored in the RAM 12 or the flash memory 16. When the user operates the operation unit 23 to select a rhythm sound source, the CPU 14 determines whether the instructed rhythm sound source has already been decoded and stored in the RAM 12 or the flash memory 16. If the instructed rhythm sound source has already been decoded and stored in the RAM 12 or the flash memory 16, it is read from the memory and output. If the instructed rhythm sound source has not been decoded, the CPU 14 reads out the corresponding rhythm sound source from the ROM 10 or the flash memory 16, decodes it, supplies it to the DAC 27, and outputs it to the outside. The rhythm sound source decoded at startup and stored in the RAM 12 or the flash memory 16 may be highlighted on the display unit 24. Various tools for analyzing user preferences are known, and can be used for automatic selection of a rhythm sound source to be decoded at startup. The user can adjust the key, pitch, and tempo of the rhythm sound source by operating the operation unit 23. The key / pitch / tempo control unit 54 of the CPU 14 controls and outputs any or all of the decoded key / pitch / tempo of the rhythm sound source according to the operation signal from the operation unit 23.

  When the user plays an electronic musical instrument such as an electric guitar, the analog audio signal is supplied from the input terminal Tin1 to the ADC 26 via the input amplifier 41. The ADC 26 converts the input external analog signal into digital data and supplies it to the CPU 14. In response to an instruction from the operation unit 23, the CPU 14 executes effect processing at the effect processing unit 59. The decoded rhythm sound source and effect-processed digital data are synthesized by the digital data synthesis unit 63, supplied to the DAC 27, and output to the outside.

<MP3 recorder>
When the user instructs recording from the operation unit 23, the MP3 audio data + external digital data or the MP3 rhythm sound source + external digital data output from the digital data synthesis unit 63 is also supplied to the MP3 encoding unit 72, and the MP3 method is used. Encoded and compressed. The encoded data is stored in the flash memory 16 via the memory controller 18 or stored in a PC connected via USB.

  As described above, in this embodiment, the rhythm sound source can be reduced by encoding and compressing the rhythm sound source in the same MP3 format as the audio data, and the rhythm sound source can be reduced with the help of the MP3 decoder for reproducing the audio data. Can be played back and output. In addition, when playing a rhythm sound source, in advance of receiving an instruction from the user in advance, considering that the rhythm sound source is repeatedly used instead of being decoded and reproduced in response to the instruction from the user, By decoding and storing in the RAM 12, the rhythm sound source can be output quickly, and the load on the CPU 14 can be reduced and distributed to other processes, improving the overall performance of the apparatus.

  In this embodiment, the rhythm sound source is compressed by the MP3 method and stored in the ROM 10 or the flash memory 16, but may be encoded by a method other than MP3, for example, AAC, ATRAC, ADPCM, WMA or the like. However, in order to share the decoder, it is preferable to encode in the same manner as the audio data.

It is a configuration block diagram of an embodiment. It is a block diagram of a conventional apparatus. It is a block diagram of the configuration of a digital data processing circuit of a conventional apparatus.

Explanation of symbols

  10 ROM, 12 RAM, 14 CPU, 16 flash memory, 18 memory controller, 22 digital data processing circuit, 23 operation unit, 24 display unit, 63 digital data synthesis unit, 70 MP3 decoding unit, 72 MP3 encoding unit.

Claims (1)

Reproduction means for decoding and reproducing an audio signal encoded by a predetermined method and recorded on the first recording medium ;
A second recording medium for recording the rhythm sound source encoded by the predetermined method;
And the reproducing means decodes and reproduces the audio signal and the rhythm sound source by a common decoding unit, and decodes at least a part of the rhythm sound source by the decoding unit when the apparatus is activated. the second recording medium or may be recorded in the third recording medium, reading and reproducing the second recording medium or said third decoded rhythm tone source which is recorded in a recording medium, in response to the operation signal An audio playback apparatus characterized by:

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